Expand Document  |  Expand Chapter  |  Full TOC  |  Printable HTML version
Basic Tests for Drugs - Pharmaceutical Substances, Medicinal Plant Materials and Dosage Forms
(1998; 100 pages) [French] [Spanish] View the PDF document
Table of Contents
View the documentPreface
View the document1. Introduction
View the document2. Other collections of simple tests
View the document3. Test procedures for pharmaceutical substances
View the document4. Test procedures for medicinal plant materials
View the document5. Test procedures for pharmaceutical dosage forms
View the document6. Reagents
View the documentAcknowledgements
View the documentOther WHO publications on pharmaceuticals
View the documentBack cover
 

5. Test procedures for pharmaceutical dosage forms

ALLOPURINOL TABLETS

Description. Each tablet usually contains 100 mg of allopurinol.

Preparation of the sample

1. Weigh 1 tablet and calculate the amount equivalent to 0.30 g of allopurinol.

2. Grind the tablets, weigh out the above-calculated equivalent amount as powdered material, triturate it with 10 ml of sodium hydroxide (0.1 mol/l) VS and filter. Acidify the filtrate with acetic acid (~60 g/l) TS, filter, wash the precipitate with 3 ml of dehydrated ethanol R and allow to dry in air for 5 minutes. Then dry at 105°C for 3 hours and use the dried material as the test substance, dividing it into 6 equal parts.

Identity tests

Colour and other reactions

1. Dissolve 1 part of the test substance in 5 ml of sodium hydroxide (~80 g/l) TS, add 1 ml of alkaline potassio-mercuric iodide TS, heat to boiling and allow to stand; a yellow, flocculent precipitate is produced.

2. Dissolve 4 parts of the test substance in a mixture of 2 ml of sodium hydroxide (~80 g/l) TS and 2 ml of water. Add 3 ml of citric acid (90 g/l) TS and shake vigorously; a white precipitate is produced.

3. Dissolve 1 part of the test substance in 25 ml of water by warming, cool and filter. To 5 ml of the filtrate (keep the unused portion for test 4) add 1 ml of ammonia (~100 g/l) TS and 1 ml of silver nitrate (40 g/l) TS; a white precipitate is produced.

4. To 5 ml of the filtrate from test 3 add 0.5 ml of copper(II) sulfate (160 g/l) TS; a blue precipitate is produced.

AMIKACIN SULFATE INJECTION

Description. The injection is a sterile solution usually containing 250 mg of amikacin sulfate in 1.0 ml of a suitable vehicle.

Preparation of the sample

1. Pool the contents of the ampoules equivalent to 1.0 g of amikacin sulfate and use directly as test solution 1, dividing it into 2 equal volumes.

2. Dilute 1 volume of test solution 1 to 25 ml with water and use it as test solution 2.

Identity tests

Colour and other reactions

1. To 3 ml of test solution 2 add 1 ml of sodium hydroxide (~80 g/l) TS, mix and add 2 ml of cobalt(II) nitrate (10 g/l) TS; a violet colour is produced.

2. To 1 volume of test solution 1 add slowly 2 ml of anthrone TS; a bluish violet colour is produced.

3. To 2 ml of test solution 2 add a few drops of barium chloride (50 g/l) TS; a white precipitate is produced which is practically insoluble in hydrochloric acid (~250 g/l) TS.

Degradation tests

Discoloration and a change in the physical state of test solution 1 usually indicate gross degradation.

AZATHIOPRINE SODIUM POWDER FOR INJECTION

Description. Each vial contains a sterile powder of azathioprine sodium usually equivalent to 50-100 mg of azathioprine.

Preparation of the sample

1. Weigh the contents of 1 vial and calculate the amount equivalent to 0.05 g of azathioprine.

2. Empty the vials, weigh out the above-calculated equivalent amount and use directly as the test substance, dividing it into 3 equal parts.

3. Dissolve 1 part of the test substance in 100 ml of water and use it as the test solution.

Identity tests

Colour and other reactions

1. To 5 ml of the test solution add 1 ml of hydrochloric acid (~70 g/l) TS and 10 mg of zinc R powder and allow to stand for 5 minutes; the colour of the solution changes to yellow. Filter, cool in ice and add 3-4 drops of sodium nitrite (10 g/l) TS and 5-6 drops of hydrochloric acid (~70 g/l) TS. Shake and allow to stand for 2 minutes. Then add about 0.25 g of urea R, shake and again allow to stand for 2 minutes. Add 0.5 ml of N-(1-naphthyl)ethylenediamine/ethanol TS; a red-violet solution is produced.

2. Transfer 2 parts of the test substance to a test-tube, add 0.05 g of potassium nitrate R and about 0.1 g of potassium hydroxide R and heat carefully until fused. Cool, dissolve the residue in 20 ml of water and filter. To 5 ml of the filtrate add 1.5 ml of hydrochloric acid (~70 g/l) TS and 5-6 drops of barium chloride (50 g/l) TS; a white turbidity appears.

3. To about 1 ml of the test solution add 0.5 ml of phosphotungstic acid (10 g/l) TS and 0.5 ml of hydrochloric acid (~70 g/l) TS; a white precipitate is produced.

BARIUM SULFATE POWDER FOR SUSPENSION

Description. A white or creamy white powder; bulky or granular.

Preparation of the sample. Use the powder directly as the test substance.

Identity tests

Colour and other reactions

1. Suspend 20 mg of the test substance in about 1 ml of hydrochloric acid (~420 g/l) TS and introduce it into a non-luminous flame using a magnesia stick or a nichrome or platinum wire sealed to a glass rod; a pale green colour appears in the flame.

2. To 0.30 g of the test substance add 10 ml of water and about 1 g of anhydrous sodium carbonate R, boil for 5 minutes and filter. Acidify the filtrate with hydrochloric acid (~420 g/l) TS and add 1 ml of barium chloride (50 g/l) TS; a white precipitate is produced.

3. To about 1 g of the test substance add 1 ml of acetic acid (~300 g/l) TS and 25 ml of water and boil. While shaking, cool and filter; if the filtrate is turbid, repeat the filtration until a clear solution is obtained and then add 1 ml of sulfuric acid (~100 g/l) TS; no opalescence is produced within 30 minutes (absence of soluble barium salts).

BECLOMETASONE DIPROPIONATE INHALATION (AEROSOL)

Description. The inhalation, supplied in a pressurized canister, contains a fine suspension of beclometasone dipropionate in a suitable propellant, usually equivalent to 50 µg per spray dose.

Preparation of the sample

1. Place 25 ml of ethanol (~750 g/l) TS in a small beaker and expel under the surface of the solvent 60 spray doses equivalent to about 3 mg of beclometasone dipropionate. Use this solution as the test solution.

2. Evaporate 10 ml of the test solution and use the residue as test substance 1.

3. Evaporate 15 ml of the test solution and use the residue as test substance 2.

Identity tests

Colour and other reactions

1. Dissolve test substance 1 in about 2 ml of sulfuric acid (~1760 g/l) TS and allow to stand for 5 minutes; a dark reddish brown solution is produced. Very cautiously pour the solution into 10 ml of water; a very light bluish grey precipitate is produced.

2. Dissolve test substance 2 in 2.0 ml of ethanol (~750 g/l) TS and add 1.0 ml of tetramethylammonium hydroxide/ethanol TS and 1.0 ml of triphenyltetrazolium chloride/ethanol TS, shaking thoroughly after each addition. Allow to stand in the dark for 20 minutes; a red colour is produced.

BENZATHINE BENZYLPENICILLIN POWDER FOR INJECTION

Description. Each vial contains a sterile powder of benzathine benzylpenicillin, usually equivalent to 1.44 g (2.4 million IU) of benzylpenicillin.

Preparation of the sample. Empty the vials and use directly as the test substance.

Identity tests

Colour and other reactions

1. To 5 mg of the test substance add 3 ml of water, 0.1 g of hydroxylamine hydrochloride R and 1 ml of sodium hydroxide (~80 g/l) TS, mix and allow to stand for 5 minutes. Then add 2 ml of hydrochloric acid (~70 g/l) TS and 0.5 ml of ferric chloride (25 g/l) TS; a violet-brown colour is produced.

2. To 2 mg of the test substance add carefully 1 drop of water and 2 ml of sulfuric acid (~1760 g/l) TS and mix; the solution is almost colourless. Heat in a water-bath for 1 minute; the solution remains almost colourless or changes to slightly yellow.

3. To 2 mg of the test substance add 1 drop of water and 2 ml of sulfuric acid (~1760 g/l) TS. After cooling, add 2 drops of formaldehyde TS; the solution remains almost colourless. Heat in a water-bath for 1 minute; a reddish brown colour is produced.

4. Dissolve 10 mg of the test substance in 1 ml of sodium hydroxide (~80 g/l) TS and add 3 ml of water and 1 ml of potassium permanganate (10 g/l) TS; a green colour is produced. Heat the solution; an odour of benzaldehyde is perceptible.

CALCIUM GLUCONATE INJECTION

Description. The injection is a sterile solution usually containing 100 mg of calcium gluconate in 1.0 ml of a suitable vehicle.

Preparation of the sample. Dilute the contents of 1 ampoule to obtain a concentration of 10 mg of calcium gluconate in 1 ml of water and use as the test solution.

Identity tests

Colour and other reactions

1. Evaporate 1 ml of the test solution to dryness over a water-bath, add 5 mg of 2-naphthol R dissolved in about 1 ml of sulfuric acid (~1760 g/l) TS and heat in a water-bath for 1 minute; a dark blue-green colour is produced.

2. To 2 ml of silver nitrate (40 g/l) TS add ammonia (~100 g/l) TS, drop by drop, until the initially formed brown precipitate just dissolves. Add 1 ml of the test solution and heat to boiling for 1-2 minutes; a silver mirror is produced.

3. To 2 ml of the test solution add 5 drops of ammonium oxalate (25 g/l) TS; a white precipitate is produced. To a portion of the precipitate add a few drops of hydrochloric acid (~70 g/l) TS; the precipitate dissolves. To the remaining precipitate add a few drops of acetic acid (~300 g/l) TS; the precipitate is practically insoluble.

Degradation test

Discoloration of the test solution usually indicates gross degradation.

CETRIMIDE CREAM

Description. The cream usually contains 5 mg of cetrimide in 1.0 g of a suitable cream base.

Preparation of the sample

1. Withdraw and weigh an amount equivalent to 10 mg of cetrimide and use directly as the test substance.

2. Withdraw and weigh an amount equivalent to 20 mg of cetrimide, transfer to a test-tube, add 10 ml of sodium chloride (100 g/l) TS and shake thoroughly. While warming in a water-bath, keep shaking to effect separation of the emulsion, remove the test-tube from the bath, cool, filter the aqueous phase and use the filtrate as the test solution.

Identity tests

Colour and other reactions

1. Transfer the test substance to a stoppered test-tube and shake with 10 ml of water; a large amount of foam is produced (keep the solution for test 2).

2. To 5 ml of the solution from test 1 add 5 ml of nitric acid (~130 g/l) TS, shake, filter and add 5 ml of silver nitrate (40 g/l) TS; a faint opalescence is produced. Allow to stand in the dark for 30 minutes; a faint yellow-grey precipitate is produced.

3. To 5 ml of water add 1 ml of sulfamic acid (100 g/l) TS, 1 drop of methyl orange/ethanol TS and 2 ml of dichloromethane R and shake; the dichloromethane layer remains colourless. Add 3 ml of the test solution (keep the unused portion for test 4) to the tube, shake and allow the layers to separate; a yellow colour is produced in the dichloromethane layer.

4. Place the remaining test solution from test 3 over a water-bath, reduce the volume to about 2 ml and add 2 ml of potassium ferricyanide (50 g/l) TS; a yellow precipitate is produced.

CHLORPROMAZINE HYDROCHLORIDE INJECTION

Description. The injection is a sterile solution usually containing 25 mg of chlorpromazine hydrochloride in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the ampoules equivalent to 0.05 g of chlorpromazine hydrochloride, evaporate to dryness over a water-bath and use the residue as the test substance.

Identity tests

Colour and other reactions

1. Dissolve 10 mg of the test substance in 1.5 ml of water and add 1 ml of tosylchloramide sodium (40 g/l) TS; a cloudy, blue-violet solution is produced. Shake; a dark resinous deposit separates on the walls of the test-tube. Add 4 ml of ethyl acetate R and shake; a red-violet colour is produced in the ethyl acetate layer.

2. Dissolve about 10 mg of the test substance in 3 ml of water and add 1 ml of ethyl acetate R, 2 drops of hydrochloric acid (~70 g/l) TS and 2 drops of chloramine B (50 g/l) TS; a red colour is produced in the aqueous layer and the ethyl acetate layer remains colourless (distinction from promethazine).

3. Dissolve the remaining test substance in 5 ml of water, add 5 drops of ammonia (~100 g/l) TS, warm until oily drops separate and filter. To the filtrate add 1 ml of nitric acid (~130 g/l) TS and a few drops of silver nitrate (40 g/l) TS; a white precipitate is produced. Separate the precipitate, wash it with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

CIMETIDINE INJECTION

Description. The injection is a sterile solution usually containing 200 mg of cimetidine in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the ampoules equivalent to 0.4 g and use directly as the test solution, dividing it into 2 equal volumes.

Identity tests

Colour and other reactions

1. Place 1 volume of the test solution in a test-tube and evaporate to dryness over a water-bath. Ignite the residue; the vapours produced darken moistened lead nitrate paper R.

2. Dilute 1 volume of the test solution with 10 ml of water. To 1 ml (keep the unused portion for test 3) add 1 drop of ammonia (~100 g/l) TS and 1 drop of copper(II) sulfate (160 g/l) TS and heat in a water-bath; a greyish green precipitate is produced which is soluble in an excess of ammonia (~100 g/l) TS.

3. To 1 ml of the diluted solution from test 2 add a few drops of potassium iodobismuthate/acetic acid TS; an orange precipitate is produced.

CLOXACILLIN SODIUM POWDER FOR INJECTION

Description. Each vial contains a sterile powder of cloxacillin sodium, usually equivalent to 500 mg of cloxacillin.

Preparation of the sample

1. Weigh the contents of 1 vial and calculate the amount equivalent to 30 mg of cloxacillin sodium.

2. Empty the vial, weigh out the above-calculated equivalent amount and use directly as the test substance, dividing it into 6 equal parts.

Identity tests

Colour and other reactions

1. Dissolve 1 part of the test substance in 3 ml of water and filter. To the filtrate add 0.10 g of hydroxylamine hydrochloride R and 1 ml of sodium hydroxide (~80 g/l) TS and allow to stand for 5 minutes. Then add 1.3 ml of hydrochloric acid (~70 g/l) TS and 0.5 ml of ferric chloride (25 g/l) TS; a dark violet-red colour is produced.

2. Dissolve 2 parts of the test substance in 2 ml of water and add 2 ml of a solution composed of 2 ml of potassio-cupric tartrate TS and 6 ml of water; a light blue solution is immediately produced.

3. Dissolve 1 part of the test substance in 1 ml of water, shake and filter. To the filtrate add 1 drop of ferric chloride (25 g/l) TS; a greenish yellow precipitate is produced.

4. To 10 mg of paraformaldehyde R dissolved in about 1 ml of sulfuric acid (~1760 g/l) TS add a small quantity of the test substance; a light yellow colour is produced. Heat the mixture in a water-bath for 2 minutes and cool; the colour of the solution changes to brownish.

5. Dissolve 1 part of the test substance in 5 ml of water and filter. Acidify with about 0.5 ml of glacial acetic acid R and filter using a coarse-porosity filter-paper. To 2 ml of the filtrate add 1 ml of magnesium uranyl acetate TS and scratch the inside of the tube with a glass rod to induce crystallization; a yellow, crystalline precipitate is produced.

DEXTRAN 70 INJECTION

Description. The injection is a sterile solution usually containing 6 g of dextran 70 in 100 ml of a suitable vehicle (normally dextrose or sodium chloride solution).

Preparation of the sample. Pool a volume equivalent to 0.12 g of dextran 70 and use directly as the test solution, dividing it into 4 equal volumes.

Identity tests

Colour and other reactions

For dextran 70 in dextrose solution:

To 1 volume of the test solution add 5 ml of potassio-cupric tartrate TS and boil; a brick-red precipitate is formed. Filter and to the filtrate add about 1.5 ml of hydrochloric acid (~420 g/l) TS. Boil for 5 minutes, cool and neutralize by adding sodium carbonate R until the effervescence ceases. Add 2 ml of potassio-cupric tartrate TS and boil again; a brick-red precipitate is again produced.

For dextran 70 in sodium chloride solution:

1. To 1 volume of the test solution add 5 ml of potassio-cupric tartrate TS and boil; the solution remains greenish and no precipitate is formed. Dilute a further 0.5 ml of the test solution to 5 ml with water and add about 0.5 ml of hydrochloric acid (~420 g/l) TS. Boil for 5 minutes, cool and neutralize by adding sodium carbonate R until the effervescence ceases. Add 2 ml of potassio-cupric tartrate TS and boil again; a brick-red precipitate is produced.

2. Introduce the test solution into a non-luminous flame using a magnesia stick or a nichrome or platinum wire sealed to a glass rod; the flame acquires an intense yellow colour.

3. Acidify 1 volume of the test solution with a small volume of nitric acid (~130 g/l) TS and add 2 ml of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash it with water and add a few drops of ammonia (~100 g/l) TS; the precipitate dissolves.

DIPHENHYDRAMINE HYDROCHLORIDE TABLETS

Description. Each tablet usually contains 25-50 mg of diphenhydramine hydrochloride.

Preparation of the sample

1. Weigh 1 tablet and calculate the amount equivalent to 0.20 g of diphenhydramine hydrochloride.

2. Grind the tablets, weigh out the above-calculated equivalent amount as powdered material and use directly as the test substance, dividing it into 4 equal parts.

Identity tests

Colour and other reactions

1. Place a small quantity of the test substance on a white test plate and add 1 drop of a mixture of about 0.5 ml of nitric acid (~1000 g/l) TS and about 0.5 ml of sulfuric acid (~1760 g/l) TS; a momentary violet colour is produced which changes to red and finally to yellow.

2. To 2 parts of the test substance add 5 ml of water, shake and filter. To the filtrate add 3 ml of hydrochloric acid (~250 g/l) TS and boil for 3 minutes. Cool the test-tube in ice and scratch the inside of the tube with a glass rod to induce crystallization. Separate the crystals and dry over silica gel, desiccant, R; melting point, about 64°C. If the melting point is lower than 64°C, recrystallize from 1-2 ml of water.

3. To 1 part of the test substance add 5 ml of water, shake and filter. To the filtrate add 0.5 ml of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash it with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

DOXORUBICIN HYDROCHLORIDE POWDER FOR INJECTION

Description. Each vial contains a sterile powder usually equivalent to 10-50 mg of doxorubicin hydrochloride.

Preparation of the sample

1. Weigh the contents of 1 vial and calculate the amount equivalent to 0.07 g of doxorubicin hydrochloride.

2. Empty the vials, weigh out the above-calculated equivalent amount and use directly as the test substance.

Identity tests

Colour and other reactions

1. Place a small quantity of the test substance on a white test plate and add 1 drop of formaldehyde/sulfuric acid TS; the orange-red colour of the substance changes to violet.

2. Dissolve about 2 mg of the test substance in 2 ml of methanol R and add 2 ml of water and 1 drop of sodium hydroxide (~80 g/l) TS; the orange-red colour of the solution changes to blue-violet.

3. Dissolve 0.05 g of the test substance in 1 ml of water, add 5 drops of ammonia (~100 g/l) TS and filter. Acidify the filtrate with nitric acid (~130 g/l) TS and add 1 ml of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced which is soluble in ammonia (~100 g/l) TS but practically insoluble in nitric acid (~1000 g/l) TS.

DOXYCYCLINE HYCLATE INJECTION

Description. The injection is a sterile solution usually containing 20 mg of doxycycline hyclate1 in 1.0 ml of a suitable vehicle.

1 Referred to as doxycycline hydrochloride in Basic tests for pharmaceutical substances, 1986.

Preparation of the sample. Pool the contents of the ampoules equivalent to 0.16 g of doxycycline hyclate and use directly as the test solution, dividing it into 4 equal volumes.

Identity tests

Colour and other reactions

1. To 1 volume of the test solution add about 2 ml of sulfuric acid (~1760 g/l) TS; an intense yellow colour is produced.

2. Place 2 ml of zinc chloride (500 g/l) TS in a porcelain dish and warm on a hotplate or over a small flame until a skin forms on the surface of the solution. Then add 2 drops of the test solution and continue to warm for 1 minute; a yellow-orange colour is produced.

3. To 1 volume of the test solution add 1 drop of ferric chloride (25 g/l) TS; a dark red-brown colour is produced.

4. To 1 volume of test solution add 0.5 ml of nitric acid (~130 g/l) TS and 0.5 ml of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash it with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

Degradation test

Discoloration of the test solution usually indicates gross degradation.

DOXYCYCLINE HYCLATE TABLETS

Description. Each tablet usually contains 100 mg of doxycycline hyclate.1

1 Referred to as doxycycline hydrochloride in Basic tests for pharmaceutical substances, 1986.

Preparation of the sample

1. Weigh 1 tablet and calculate the amounts equivalent to 0.10 g and 25 mg of doxycycline hyclate.

2. Grind the tablets, weigh out the above-calculated equivalent amounts as powdered material and use directly, 0.10 g as test substance 1 and 25 mg as test substance 2.

3. Shake test substance 1 with 10 ml of water and filter. Use the filtrate as the test solution.

Identity tests

Colour and other reactions

1. To test substance 2 add about 2 ml of sulfuric acid (~1760 g/l) TS; an intense yellow colour is produced.

2. Place 2 ml of zinc chloride (500 g/l) TS in a porcelain dish and warm on a hotplate or over a small flame until a skin forms on the surface of the solution. Then add 2 drops of the test solution and continue to warm for 1 minute; a yellow-orange colour is produced.

3. To 2 ml of the test solution add 1 drop of ferric chloride (25 g/l) TS; a dark red-brown colour is produced.

4. To 1 ml of the test solution add 0.5 ml of nitric acid (~130 g/l) TS and 0.5 ml of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash it with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

EPINEPHRINE HYDROGEN TARTRATE INJECTION

Description. The injection is a sterile solution of epinephrine hydrogen tartrate, usually containing the equivalent of 1.0 mg of epinephrine in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the ampoules equivalent to 10 mg of epinephrine hydrogen tartrate; if necessary, reduce the volume by evaporation to 10 ml or dilute to 10 ml with water. Use directly as the test solution.

Identity tests

Colour and other reactions

1. To 5 ml of the test solution add 1-2 drops of ferric chloride (25 g/l) TS; a green solution is produced. Add 1 drop of ammonia (~260 g/l) TS; the colour changes to dark red.

2. To 2 ml of the test solution add 1 ml of sulfuric acid (~5 g/l) TS and 3 ml of ammonium molybdate (95 g/l) TS and mix; an orange colour is produced. Then add slowly, while mixing, 2 ml of sodium hydroxide (~80 g/l) TS; a yellow-green solution is produced.

3. To 2 ml of the test solution add 2 ml of potassium bromide (100 g/l) TS, 2 ml of resorcinol (20 g/l) TS and 3 ml of sulfuric acid (~1760 g/l) TS. Heat in a water-bath for 5-10 minutes; a dark blue colour is produced which changes to red when the solution is cooled and poured into water.

FERROUS FUMARATE TABLETS

Description. Each tablet contains ferrous fumarate, usually equivalent to 60 mg of iron.

Preparation of the sample

1. Weigh 1 tablet and calculate the amounts equivalent to 0.5 g and 0.05 g of ferrous fumarate.

2. Grind the tablets, weigh out the above-calculated equivalent amounts as powdered material and use directly, 0.5 g as test substance 1 and 0.05 g as test substance 2.

Identity tests

Colour and other reactions

1. To test substance 1 add 20 ml of sulfuric acid (~100 g/l) TS and heat in a water-bath for 15 minutes. Filter while hot and cool the filtrate in ice; a white precipitate is produced (keep the filtrate for test 2). Wash the precipitate with acidified water and dry at 105°C. Dissolve the precipitate in 5 ml of sodium carbonate (50 g/l) TS and add 0.5 ml of potassium permanganate (10 g/l) TS; the colour of the permanganate fades and a brownish solution is produced.

2. To 2 ml of the filtrate obtained in test 1 add 2 ml of potassium ferricyanide (50 g/l) TS; an intense dark blue precipitate is produced which is insoluble in hydrochloric acid (~70 g/l) TS.

3. Mix test substance 2 with 0.10 g of resorcinol R, add 5-10 drops of sulfuric acid (~1760 g/l) TS and heat gently; a deep red, semi-solid mass is produced. Cool, add 25 ml of water, swirl to dissolve and filter. To 1 ml of the filtrate add 10 ml of water and mix; an orange-yellow solution is produced which exhibits a green fluorescence. Make the solution alkaline by adding a few drops of sodium hydroxide (~80 g/l) TS; a red solution is produced which exhibits a green fluorescence.

FLUCYTOSINE TABLETS

Description. Each tablet usually contains 500 mg of flucytosine.

Preparation of the sample

1. Weigh 1 tablet and calculate the amount equivalent to 0.30 g of flucytosine.

2. Grind the tablets, weigh out the above-calculated equivalent amount as powdered material, shake with 30 ml of water, filter and use the filtrate as the test solution, dividing it into 6 equal volumes.

3. Evaporate 2 volumes of the test solution to dryness over a water-bath and use the residue as the test substance.

Identity tests

Melting behaviour. The test substance melts at about 295°C with decomposition.

Colour and other reactions

1. To 1 volume of the test solution add 5 ml of water, 1.5 ml of hydrochloric acid (~250 g/l) TS and 0.5 ml of sodium nitrite (10 g/l) TS and shake for 2 minutes. Add 0.5 ml of 2-naphthol TS; a yellowish brown precipitate is produced.

2. To 1 volume of the test solution add 5 ml of water and 2 ml of silver nitrate (40 g/l) TS, shake and allow to stand for 2-3 minutes; a white precipitate is produced.

3. To 0.5 volume of the test solution add 2 ml of bromine TS; the colour of bromine is discharged. Add 4 ml of freshly prepared barium hydroxide (40 g/l) TS; a purple precipitate is produced.

4. Mix 3 drops of potassium dichromate (100 g/l) TS with about 0.5 ml of sulfuric acid (~1760 g/l) TS and heat in a water-bath for 5 minutes; the solution wets the sides of the tube. Add 10 mg of the test substance, shake well and heat again for 5 minutes in a water-bath; the colour changes to green and the solution no longer wets the sides of the tube.

GENTAMICIN SULFATE INJECTION

Description. The injection is a sterile solution usually containing 10-40 mg of gentamicin sulfate in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the ampoules equivalent to 0.20 g of gentamicin sulfate; if necessary, reduce the volume by evaporation to about 5 ml or dilute to 5 ml with water. Use directly as the test solution.

Identity tests

Colour and other reactions

1. To 1 ml of the test solution add a solution of 5 mg of 1-naphthol R dissolved in 1 drop of ethanol (~750 g/l) TS, 4 drops of water and about 0.5 ml of sulfuric acid (~1760 g/l) TS; a yellow colour is produced.

2. To 1 ml of the test solution add a solution of 20 mg of triketohydrindene hydrate R dissolved in 2 ml of water and 0.10 g of sodium acetate R. Mix and heat in a water-bath for 5 minutes; a dark violet colour is produced.

3. Dilute 1 ml of the test solution with 1 ml of water and add 5 drops of alkaline potassio-mercuric iodide TS; a yellowish white, turbid solution is produced.

4. Dilute 1 ml of the test solution with 2 ml of water and add 5 drops of hydrochloric acid (~70 g/l) TS and 5 drops of barium chloride (50 g/l) TS; a white precipitate is produced.

HYDRALAZINE HYDROCHLORIDE TABLETS

Description. Each tablet usually contains 25-50 mg of hydralazine hydrochloride.

Preparation of the sample

1. Weigh 1 tablet and calculate the amounts equivalent to 5 mg and 0.05 g of hydralazine hydrochloride.

2. Grind the tablets, weigh out the above-calculated equivalent amounts as powdered material and use directly, 5 mg as test substance 1 and 0.05 g as test substance 2.

3. Shake test substance 2 with 5 ml of water, filter and use the filtrate as the test solution.

Identity tests

Colour and other reactions

1. Shake test substance 1 with 2 ml of water, add 3 drops of freshly prepared ferrous sulfate (15 g/l) TS and heat to boiling for 3 minutes; a brown-red colour is produced. Add 5-10 drops of iodine TS; the colour changes to dark violet.

2. To about 1 ml of the test solution add 0.5 ml of nitric acid (~130 g/l) TS and 5 ml of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash it with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

3. To 4 ml of the test solution add a mixture of 100 ml of water and 8 ml of hydrochloric acid (~70 g/l) TS, then add 20 ml of sodium nitrite (10 g/l) TS and allow to stand for 10 minutes; a white to ivory-coloured precipitate is produced.

HYDROCORTISONE OINTMENT

Description. The ointment usually contains 10-25 mg of hydrocortisone in 1.0 g of a suitable ointment base.

Preparation of the sample. Withdraw and weigh an amount equivalent to 20 mg of hydrocortisone, add 10 ml of ethanol (~750 g/l) TS and heat in a water-bath for 5 minutes with frequent shaking. Cool to solidify the ointment base, filter and use the filtrate as the test solution, dividing it into 4 equal volumes.

Identity tests

Colour and other reactions

1. Evaporate 1 volume of the test solution to dryness over a water-bath. Add about 2 ml of sulfuric acid (~1760 g/l) TS and allow to stand for 5 minutes; a yellow solution is produced with a greenish fluorescence. Very cautiously pour the solution into 10 ml of water; the colour of the solution changes to brownish yellow, but the fluorescence remains (certain excipients may interfere with the reaction and the colour of the solution may fade to nearly colourless).

2. Evaporate 1 volume of the test solution to dryness over a water-bath. Add about 1 ml of phosphoric acid (~1440 g/l) TS and heat cautiously; the solution, initially colourless, changes to yellow and shows a slightly greenish fluorescence.

3. Evaporate 2 volumes of the test solution to about 2 ml over a water-bath and add an equal volume of potassio-cupric tartrate TS; an orange-red precipitate is produced.

HYDROCORTISONE ACETATE CREAM

Description. The cream usually contains 10 mg of hydrocortisone acetate in 1.0 g of a suitable cream base.

Preparation of the sample. Withdraw and weigh an amount equivalent to 0.10 g of hydrocortisone acetate, add 30 ml of methanol R, boil and cool in ice for 30 minutes. Filter, evaporate the filtrate to dryness and use the residue as the test substance.

Identity tests

Colour and other reactions

1. Dissolve about 2 mg of the test substance in about 2 ml of sulfuric acid (~1760 g/l) TS and allow to stand for 5 minutes; a yellow solution with a greenish fluorescence is produced. Very cautiously pour the solution into 10 ml of water; the colour of the solution changes to brownish yellow, but the fluorescence remains (certain excipients may interfere with the reaction and the colour of the solution may fade to nearly colourless within a very short period of time).

2. Dissolve about 2 mg of the test substance in about 1 ml of phosphoric acid (~1440 g/l) TS. Heat cautiously; the colourless solution changes to yellow and shows a slightly greenish fluorescence.

3. Dissolve 20 mg of the test substance in 2 ml of methanol R. Add 1 ml of tetramethylammonium hydroxide/ethanol TS and 1 ml of triphenyltetrazolium chloride/ethanol TS, mixing thoroughly after each addition, and allow to stand in the dark for 20 minutes; a red colour is produced.

4. Place 15 mg of the test substance in a test-tube and add 3 drops of phosphoric acid (~1440 g/l) TS. Close the tube with a stopper through which passes a smaller test-tube filled with water to act as a condenser. Allow a drop of lanthanum nitrate (30 g/l) TS to hang on the outside of this smaller tube. Heat the apparatus in a water-bath for 5 minutes. Transfer the drop of lanthanum nitrate to a white test plate, mix it with 1 drop of iodine (0.05 mol/l) VS and add, at the edge of the two liquids, 1 drop of ammonia (~100 g/l) TS; after 1-2 minutes a blue colour is produced at the interface of the two liquids which persists for a short time.

HYDROCORTISONE SODIUM SUCCINATE POWDER FOR INJECTION

Description. Each vial contains a sterile powder usually equivalent to 100 mg of hydrocortisone sodium succinate.

Preparation of the sample

1. Weigh the contents of 1 vial and calculate the amount equivalent to 0.10 g of hydrocortisone sodium succinate.

2. Empty the vial, weigh out the above-calculated equivalent amount and use directly as the test substance.

Identity tests

Colour and other reactions

1. Dissolve about 2 mg of the test substance in 1 ml of alkaline potassio-mercuric iodide TS; a dark precipitate is produced.

2. Dissolve a small quantity of the test substance in about 2 ml of sulfuric acid (~1760 g/l) TS and allow to stand for 5 minutes; a yellow solution with a greenish fluorescence is produced. Very cautiously pour the solution into 10 ml of water; the colour of the solution changes to brownish yellow, but the fluorescence remains (certain excipients may interfere with the reaction and the colour may fade to nearly colourless within a very short period of time).

3. Dissolve a small quantity of the test substance in about 1 ml of phosphoric acid (~1440 g/l) TS and heat cautiously; a yellow solution with a pale greenish fluorescence is produced.

4. Dissolve about 2 mg of the test substance in 1 ml of water and introduce the solution into a non-luminous flame using a magnesia stick or a nichrome or platinum wire sealed to a glass rod; the flame acquires an intense yellow colour.

5. Heat carefully 10 mg of the test substance with 1 drop of water, 10 mg of resorcinol R and 3 drops of sulfuric acid (~1760 g/l) TS, cool and add 2 ml of water. Cool again and pour the solution into a mixture of 100 ml of water and 1 ml of sodium hydroxide (~400 g/l) TS; a yellowish green fluorescence appears.

INDOMETACIN TABLETS

Description. Each tablet usually contains 25 mg of indometacin.

Preparation of the sample

1. Weigh 1 tablet and calculate the amount equivalent to 0.05 g of indometacin.

2. Grind the tablets, weigh out the above-calculated equivalent amount as powdered material and use directly as the test substance, dividing it into 2 equal parts.

Identity tests

Colour and other reactions

1. To 1 part of the test substance add 1 ml of water and 1 drop of sodium hydroxide (~80 g/l) TS, shake and filter. To the filtrate add 1 ml of sodium nitrite (10 g/l) TS, allow to stand for 5 minutes and cautiously add 0.5 ml of hydrochloric acid (~250 g/l) TS; a green colour is produced.

2. Mix 1 part of the test substance with 2 ml of water and 2 ml of sodium hydroxide (~80 g/l) TS; a strong yellow colour is produced which fades rapidly.

IRON DEXTRAN INJECTION

Description. The injection is a sterile solution of iron dextran, usually containing the equivalent of 50 mg of iron in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the ampoules equivalent to 0.15 g of iron; if necessary, reduce the volume to about 3 ml or dilute with water to 3 ml. Use directly as the test solution.

Identity tests

Colour and other reactions

1. Place 1 ml of the test solution on a watch-glass and add 2 drops of ammonia (~260 g/l) TS; no precipitate is observed. Add about 2 ml of hydrochloric acid (~420 g/l) TS, mix and add about 2 ml of ammonia (~260 g/l) TS; a reddish brown precipitate is produced.

2. Acidify 1 ml of the test solution with hydrochloric acid (~70 g/l) TS and add 1 ml of ammonium thiocyanate (75 g/l) TS; a blood-red colour is produced. Extract with 5 ml of amyl alcohol R and add a few drops of mercuric chloride (65 g/l) TS or phosphoric acid (~1440 g/l) TS; the colour is discharged.

3. Dilute about 0.2 ml of the test solution with 20 ml of water. To 10 ml of this solution add 4 drops of hydrochloric acid (~420 g/l) TS and boil for 30 seconds. Cool rapidly and add 4 ml of ammonia (~260 g/l) TS and 10 ml of hydrogen sulfide TS. Boil to remove the excess hydrogen sulfide, cool and filter. Boil 5 ml of the filtrate with 5 ml of potassio-cupric tartrate TS; the colour of the solution remains greenish and no precipitate is produced. Boil a further 5 ml of the filtrate with about 0.5 ml of hydrochloric acid (~420 g/l) TS for 5 minutes, cool, add 2.5 ml of sodium hydroxide (~80 g/l) TS and 5 ml of potassio-cupric tartrate TS and boil again; a reddish precipitate is produced.

KETAMINE HYDROCHLORIDE INJECTION

Description. The injection is a sterile solution of ketamine hydrochloride, usually containing the equivalent of 50 mg of ketamine in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the ampoules equivalent to 0.15 g of ketamine hydrochloride and use directly as the test solution, dividing it into 3 equal volumes.

Identity tests

Colour and other reactions

1. To one-third of 1 volume of the test solution add a few drops of sodium hydroxide (~80 g/l) TS; a white turbidity is produced. Add a few drops of methanol R; the turbidity disappears.

2. To one-third of 1 volume of the test solution add 0.5 ml of trinitrophenol/ethanol TS; a yellow precipitate is produced.

3. Acidify one-third of 1 volume of the test solution with a small volume of nitric acid (~130 g/l) TS and add 2 ml of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash it with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

4. Evaporate 2 volumes of the test solution to dryness. Recrystallize the residue from ethanol (~750 g/l) TS and dry at 105°C for 2 hours; melting point, about 261°C.

LEVOTHYROXINE SODIUM TABLETS

Description. Each tablet usually contains 50-100 µg of levothyroxine sodium.

Preparation of the sample

1. Weigh 1 tablet and calculate the amount equivalent to 5 mg of levothyroxine sodium.

2. Grind the tablets, weigh out the above-calculated equivalent amount as powdered material and use directly as test substance 1, dividing it into 2 equal parts.

3. Divide 1 part of test substance 1 into 5 equal parts and use as test substance 2.

4. Shake 2 parts of test substance 2 with 3 ml of dehydrated ethanol R for 5 minutes, then allow to stand for 5 minutes. Place a strip of filter-paper into the suspension and allow the liquid to ascend about 4 cm. Take out the strip, cut away the lower dipped portion as well as the part that has not been wetted by the solution, dry the remaining part of the strip in air at room temperature and use as the test paper.

Identity tests

Colour and other reactions

1. To 1 part of test substance 2 add 1.5 ml of ethanol (~750 g/l) TS, 1.5 ml of water and 0.5 ml of sodium hydroxide (~80 g/l) TS, shake well and filter. To the filtrate add about 0.5 ml of hydrochloric acid (~250 g/l) TS and 0.2 ml of sodium nitrite (100 g/l) TS; a yellow colour is produced. Allow to stand for 5 minutes and add 1 drop of ammonia (~260 g/l) TS; the colour of the solution changes to orange-red.

2. Place 1 part of test substance 2 in a silica crucible and ignite. To the residue add 2 ml of water, shake and filter. To the filtrate add 0.5 ml of magnesium uranyl acetate TS and allow to stand for a few minutes; a yellow precipitate is produced.

3. Heat test substance 1 with about 0.2 g of sodium carbonate R. To the fused mass add 3 ml of water, shake and filter. Acidify the filtrate with a few drops of hydrochloric acid (~250 g/l) TS and add 2-3 drops of starch TS; a blue-violet colour is produced.

4. Place 1 drop of triketohydrindene/ethanol TS on the test paper and place in an oven at 105°C for 5 minutes; a violet spot or ring is produced.

LIDOCAINE HYDROCHLORIDE JELLY

Description. The jelly usually contains 20-40 mg of lidocaine hydrochloride in 1.0 g of a suitable water-soluble, viscous base.

Preparation of the sample

1. Add 10-15 ml of water to a separator, add a quantity of the jelly equivalent to 0.15 g of lidocaine hydrochloride and mix. Add 2.0 ml of ammonia (~100 g/l) TS and extract with 2 portions of 30 ml of dichloromethane R. Evaporate the combined dichloromethane extracts to dryness with the aid of a current of warm air and use the residue as test substance 1.

2. Withdraw and weigh an amount equivalent to 0.20 g of lidocaine hydrochloride and use directly as test substance 2, dividing it into 3 equal parts.

Identity tests

Colour and other reactions

1. To test substance 1 add 1 ml of ethanol (~750 g/l) TS and 0.5 ml of cobalt(II) chloride (30 g/l) TS and shake for 2 minutes; a bluish green precipitate is produced.

2. To 1 part of test substance 2 add 2 ml of water and 3 drops of iodine TS and mix; a brown precipitate is produced.

3. Shake 2 parts of test substance 2 with 5 ml of water and add 1 ml of nitric acid (~130 g/l) TS and 1 ml of silver nitrate (40 g/l) TS; a white precipitate is produced. Separate the precipitate, wash it with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

MAGNESIUM HYDROXIDE ORAL SUSPENSION

Description. The suspension usually contains the equivalent of 55 mg of magnesium oxide in 1.0 ml of a suitable vehicle.

Preparation of the sample. Take a portion of the suspension equivalent to 0.20 g of magnesium hydroxide and use directly as the test solution, dividing it into 2 equal volumes.

Identity tests

Colour and other reactions

1. To 1 volume of the test solution add 5 ml of hydrochloric acid (~70 g/l) TS and filter. To the filtrate add 5 ml of ammonium chloride (100 g/l) TS, 3 ml of disodium hydrogen phosphate (100 g/l) TS and 5 ml of ammonia (~100 g/l) TS; a white precipitate is produced which is soluble in acetic acid (~300 g/l) TS.

2. To 1 volume of the test solution add 5 ml of hydrochloric acid (~70 g/l) TS and 5 ml of sodium hydroxide (~80 g/l) TS; a white, gelatinous precipitate is produced which is insoluble in an excess of sodium hydroxide (~80 g/l) TS. Add a few drops of iodine TS; the colour of the precipitate changes to dark brown.

MAGNESIUM SULFATE POWDER

Description. Brilliant, colourless crystals or a white, crystalline powder; odourless.

Preparation of the sample. Use the powder directly as the test substance.

Identity tests

Colour and other reactions

1. Dissolve 10 mg of the test substance in 2 ml of water and add 1 ml of ammonia (~100 g/l) TS; a white precipitate is produced. Add 1 ml of ammonium chloride (100 g/l) TS; the precipitate dissolves. Add 1 ml of disodium hydrogen phosphate (100 g/l) TS; a white precipitate is produced.

2. Dissolve 10 mg of the test substance in 2 ml of water and add 3 drops of titan yellow TS and 2 ml of sodium hydroxide (~80 g/l) TS; a distinct pink colour is produced.

3. Dissolve 0.05 g of the test substance in 5 ml of water and add 1 ml of hydrochloric acid (~70 g/l) TS and 1 ml of barium chloride (50 g/l) TS; a white precipitate is produced.

METHYLROSANILINIUM CHLORIDE SOLUTION

Description. The solution usually contains 10 mg of methylrosanilinium chloride (gentian violet) in 1.0 ml of a suitable vehicle.

Preparation of the sample. Take a volume of the solution equivalent to 25 mg of methylrosanilinium chloride and use directly as the test solution.

Identity tests

Colour and other reactions

1. Add 2 drops of the test solution to about 1 ml of sulfuric acid (~1760 g/l) TS and shake; an orange or brown-red colour is produced. Cautiously dilute with water; the colour changes to brown, then to green and finally to blue.

2. Dilute the remaining test solution to 10 ml with water and add 5 drops of hydrochloric acid (~420 g/l) TS. To 5 ml of this solution (keep the unused portion for test 3) add, drop by drop, 0.6 ml of tannic acid (100 g/l) TS; a deep blue precipitate is produced.

3. To the remaining solution from test 2 add about 1 ml of hydrochloric acid (~420 g/l) TS and 0.5 g of zinc R powder; a gas is evolved and the solution fades rapidly. Filter and, on a filter-paper, place 1 drop of the filtrate adjacent to 1 drop of ammonia (~100 g/l) TS; a blue colour is produced at the zone of contact.

METOCLOPRAMIDE HYDROCHLORIDE INJECTION

Description. The injection is a sterile solution usually containing 5 mg of metoclopramide hydrochloride in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the ampoules equivalent to 0.06 g of metoclopramide hydrochloride and use directly as the test solution, dividing it into 6 equal volumes.

Identity tests

Colour and other reactions

1. To 2 volumes of the test solution add 1 ml of hydrochloric acid (~70 g/l) TS and 2 ml of sodium nitrite (10 g/l) TS; a yellow colour is produced.

2. To 2 volumes of the test solution add 1 drop of sulfuric acid (~1760 g/l) TS, 1 drop of potassium bromide (100 g/l) TS and 2 drops of potassium bromate (15 g/l) TS; a green colour is produced.

3. Mix 2 drops of potassium bromide (100 g/l) TS with 4 drops of potassium bromate (15 g/l) TS and dilute to about 1 ml with water. Add 2 drops of sulfuric acid (~1760 g/l) TS and 1 volume of the test solution; a yellowish precipitate is produced.

4. To 1 volume of the test solution add 1 ml of nitric acid (~130 g/l) TS and 1 ml of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash it with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

METOCLOPRAMIDE HYDROCHLORIDE TABLETS

Description. Each tablet usually contains 10 mg of metoclopramide hydrochloride.

Preparation of the sample

1. Weigh 1 tablet and calculate the amount equivalent to 0.35 g of metoclopramide hydrochloride.

2. Grind the tablets and weigh out the above-calculated equivalent amount as powdered material, shake it with 10 ml of water and filter. Use the filtrate as the test solution, dividing it into 3 equal volumes.

Identity tests

Colour and other reactions

1. To 1 volume of the test solution add 1 ml of hydrochloric acid (~70 g/l) TS and 2 ml of sodium nitrite (10 g/l) TS; a yellow colour is produced.

2. Mix 2 drops of potassium bromide (100 g/l) TS with 4 drops of potassium bromate (15 g/l) TS and dilute to 1 ml with water. Add 2 drops of sulfuric acid (~1760 g/l) TS and 1 volume of the test solution; a yellowish precipitate is produced.

3. To 1 volume of the test solution add 1 ml of nitric acid (~130 g/l) TS and 1 ml of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash it with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

METRONIDAZOLE SUPPOSITORIES

Description. Each suppository usually contains 500 mg - 1 g of metronidazole.

Preparation of the sample. Dissolve a quantity of the suppository equivalent to 0.5 g of metronidazole in 20 ml of hot water. Allow to stand overnight to crystallize. Filter to separate the crystals, dry them at 105°C for about 3 hours and use as the test substance.

Identity tests

Description of the test substance. A white or pale yellow, crystalline powder.

Melting point of the test substance. About 161°C.

Colour and other reactions

1. To 20 mg of the test substance add 0.05 g of 4-dimethylaminobenzaldehyde R dissolved in 2 ml of hydrochloric acid (~70 g/l) TS; the solution is almost colourless or has a yellow tint. Add 0.05 g of zinc R powder; a deep red colour is produced.

2. Boil 20 mg of the test substance with 5 ml of sodium hydroxide (~80 g/l) TS; the solution shows the following colours in turn: pink, pink-violet, red-violet, red, red-brown, yellow-brown and yellow.

MICONAZOLE NITRATE CREAM

Description. The cream usually contains 20 mg of miconazole nitrate in 1.0 g of a suitable cream base.

Preparation of the sample

1. Withdraw and weigh an amount equivalent to 0.10 g of miconazole nitrate and use directly as the test substance, dividing it into 2 equal parts.

2. Dissolve 1 part of the test substance in sufficient methanol R to produce 50 ml, filter, and use as the test solution.

Identity tests

Colour and other reactions

1. To 1 part of the test substance add 2 ml of sodium hydroxide (~80 g/l) TS and 20 g of zinc R powder. Boil gently; ammonia is produced which shows an alkaline range on moistened pH-indicator paper R.

2. Place 5 ml of the test solution in a porcelain crucible, add 0.1 g of anhydrous sodium carbonate R, evaporate to dryness over a water-bath and ignite. Cool, dissolve the residue in 3 ml of nitric acid (~130 g/l) TS and add a few drops of silver nitrate (40 g/l) TS; a white precipitate is produced. Separate the precipitate, wash with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

3. Cool 3 ml of the test solution in ice and add 0.4 ml of potassium chloride (100 g/l) TS, 0.1 ml of diphenylamine/sulfuric acid TS and 10 ml of sulfuric acid (~1760 g/l) TS; an intense blue colour is produced.

NICLOSAMIDE TABLETS

Description. Each tablet usually contains 500 mg of niclosamide.

Preparation of the sample

1. Weigh 1 tablet and calculate the amount equivalent to 0.25 g of niclosamide.

2. Grind the tablets, weigh out the above-calculated equivalent amount as powdered material, shake it with 20 ml of acetone R and filter. Evaporate the filtrate to dryness over a water-bath and use the residue as the test substance.

Identity tests

Melting point of the test substance. About 228°C.

Colour and other reactions

1. To 0.05 g of the test substance add 5 ml of hydrochloric acid (~70 g/l) TS and about 0.1 g of zinc R powder, heat over a water-bath for 10 minutes, cool and filter. To the filtrate add 1 ml of sodium nitrite (10 g/l) TS, shake and cool in ice for 2-3 minutes. Add 1 g of urea R, swirl until dissolved and allow to stand for 10 minutes. Add 2 ml of 2-naphthol TS and 2 ml of sodium hydroxide (~400 g/l) TS; a dark red colour is produced.

2. Place about 0.1 g of the test substance in a mortar and mix quickly with about 0.1 g of ground sodium hydroxide R. Transfer to a porcelain crucible and heat until melted. Cool, dissolve the melt in 4 ml of nitric acid (~130 g/l) TS, filter and to 1 ml of the filtrate add 5 drops of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash with water and add about 0.4 ml of ammonia (~260 g/l) TS; the precipitate dissolves but precipitates again on the addition of about 0.75 ml of nitric acid (~1000 g/l) TS.

3. Shake 20 mg of the test substance with 5 ml of ethanol (~750 g/l) TS; a yellow solution is produced. Add 1 drop of sodium hydroxide (~80 g/l) TS; the yellow colour becomes more intense. Then add 2 drops of hydrochloric acid (~70 g/l) TS; the yellow colour fades and a colourless solution is produced.

NYSTATIN OINTMENT

Description. The ointment usually contains 100 000 IU of nystatin in 1.0 g of a suitable ointment base.

Preparation of the sample. Withdraw and weigh an amount equivalent to 22 000 IU of nystatin, add 25 ml of dimethylformamide R and shake well. Filter, evaporate the filtrate to dryness and use the residue as the test substance.

Identity tests

Colour and other reactions

1. To 5 mg of the test substance add about 2 ml of sulfuric acid (~1760 g/l) TS; a dark violet colour is produced.

2. To 5 mg of the test substance add 1 ml of ethanol (~750 g/l) TS and about 1 ml of hydrochloric acid (~250 g/l) TS, shake and filter. To the filtrate add a few crystals of resorcinol R and heat in a water-bath for 2 minutes; a pink colour is produced.

3. To 5 mg of the test substance add 2 ml of ethanol (~750 g/l) TS, shake and filter. To the filtrate add about 1 ml of hydrochloric acid (~250 g/l) TS and 2 drops of a solution composed of 1 ml of ferric chloride (25 g/l) TS and 10 ml of water; a dark green colour is produced.

NYSTATIN PESSARIES

Description. Each pessary usually contains 100 000 IU of nystatin.

Preparation of the sample

1. Weigh 1 pessary and calculate the amount equivalent to 22 000 IU of nystatin.

2. Grind the pessaries, weigh out the above-calculated equivalent amount as powdered material, shake it vigorously with 25 ml of dimethylformamide R, filter, evaporate the filtrate to dryness and use the residue as the test substance.

Identity tests

Colour and other reactions

1. To 5 mg of the test substance add about 2 ml of sulfuric acid (~1760 g/l) TS; a dark violet colour is produced.

2. To 5 mg of the test substance add 1 ml of ethanol (~750 g/l) TS and about 1 ml of hydrochloric acid (~250 g/l) TS, shake and filter. To the filtrate add a few crystals of resorcinol R and heat in a water-bath for 2 minutes; a pink colour is produced.

3. To 5 mg of the test substance add 2 ml of ethanol (~750 g/l) TS, shake and filter. To the filtrate add about 1 ml of hydrochloric acid (~250 g/l) TS and 2 drops of a solution composed of 1 ml of ferric chloride (25 g/l) TS and 10 ml of water; a dark green colour is produced.

ORAL REHYDRATION SALTS (COMPOSITION A)

Description. Each packet contains a white, crystalline powder composed of:

glucose, anhydrous

20.0 g

sodium chloride

3.5 g

sodium hydrogen carbonate

2.5 g

potassium chloride

1.5 g

Preparation of the sample

1. Weigh the contents of 1 packet; it should weigh between 26.0 g and 29.0 g.

2. Use the contents of 1 packet directly as the test substance.

3. Dissolve the contents of 1 packet in 250 ml of water and use as the test solution.

Identity tests

Melting behaviour. Gently heat a small quantity of the test substance; the melt changes first to yellow and then to brown and an odour of burning sugar is perceptible. Then ignite; the melt swells, ignites and chars.

Colour and other reactions

1. The test solution is slightly alkaline when tested with pH-indicator paper R.

2. Add a few drops of the test solution to 5 ml of hot potassio-cupric tartrate TS; a copious red precipitate is produced (glucose).

3. Acidify 5 ml of the test solution with acetic acid (~300 g/l) TS, add 2 ml of magnesium uranyl acetate TS and scratch the sides of the beaker with a glass rod; a light yellow, crystalline precipitate is slowly produced (sodium).

Alternative test:

Introduce the test solution into a non-luminous flame using a magnesia stick or a nichrome or platinum wire sealed to a glass rod; the flame acquires an intense yellow colour (sodium).

4. To 5 ml of the test solution add 0.5 ml of nitric acid (~130 g/l) TS and 0.5 ml of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves (chlorides).

5. To 5 ml of the test solution add 2 drops of phenolphthalein/ethanol TS; a pink colour is produced. Heat to boiling; a gas is evolved and the colour of the solution changes to red-violet (hydrogen carbonate).

6. To 5 ml of the test solution add 1 ml of acetic acid (~60 g/l) TS and 4 drops of sodium cobaltinitrite (100 g/l) TS; a yellow-orange precipitate is produced (potassium).

ORAL REHYDRATION SALTS (COMPOSITION B)

Description. Each packet contains a white, crystalline powder composed of:

glucose, anhydrous

20.0 g

sodium chloride

3.5 g

sodium citrate dihydrate

2.9 g

potassium chloride

1.5 g

Preparation of the sample

1. Weigh the contents of 1 packet; it should weigh between 26.5 g and 29.5 g.

2. Use the contents of 1 packet directly as the test substance.

3. Dissolve the contents of 1 packet in 250 ml of water and use as the test solution.

Identity tests

Melting behaviour. Gently heat a small quantity of the test substance; the melt changes first to yellow and then to brown and an odour of burning sugar is perceptible. Then ignite; the melt swells, ignites and chars.

Colour and other reactions

1. The test solution is slightly alkaline when tested with pH-indicator paper R.

2. Add a few drops of the test solution to 5 ml of hot potassio-cupric tartrate TS; a copious red precipitate is produced (glucose).

3. Acidify 5 ml of the test solution with acetic acid (~300 g/l) TS, add 2 ml of magnesium uranyl acetate TS and scratch the sides of the beaker with a glass rod; a light yellow, crystalline precipitate is slowly produced (sodium).

Alternative test:

Introduce the test solution into a non-luminous flame using a magnesia stick or a nichrome or platinum wire sealed to a glass rod; the flame acquires an intense yellow colour (sodium).

4. To 5 ml of the test solution add 0.5 ml of nitric acid (~130 g/l) TS and 0.5 ml of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves (chlorides).

5. To 5 ml of the test solution add 3 ml of calcium chloride (55 g/l) TS; no precipitate is produced. Boil the solution; a white solid is produced which is soluble in acetic acid (~300 g/l) TS (citrates).

6. To 5 ml of the test solution add 1 ml of acetic acid (~60 g/l) TS and 4 drops of sodium cobaltinitrite (100 g/l) TS; a yellow-orange precipitate is produced (potassium).

PARACETAMOL SUPPOSITORIES

Description. Each suppository usually contains 100 mg of paracetamol.

Preparation of the sample

1. Weigh 1 suppository and calculate the amount equivalent to 0.5 g of paracetamol.

2. Dissolve a quantity of the suppositories equivalent to 0.5 g of paracetamol in 25 ml of light petroleum R by warming carefully over a water-bath. Collect the residue by decanting, wash with 3 portions of 25 ml of light petroleum R and use as the test substance.

Identity tests

Description of the test substance. A white, crystalline powder.

Melting point of the test substance. About 170°C.

Eutectic temperature of the test substance. With benzanilide R, about 137°C; with phenacetin R, about 114°C.

Colour and other reactions

1. Dissolve 0.10 g of the test substance in 10 ml of water and add 1 drop of ferric chloride (~25 g/l) TS; an intense violet-blue colour is produced.

2. To 0.10 g of the test substance add 1 ml of hydrochloric acid (~70 g/l) TS and boil for 1 minute. Add 10 ml of water and cool; no precipitate is produced. Add 1 drop of potassium dichromate (100 g/l) TS and shake; a violet colour slowly develops and does not change to red (distinction from phenacetin).

PHENYTOIN TABLETS

Description. Each tablet usually contains 50 mg of phenytoin.

Preparation of the sample

1. Weigh 1 tablet and calculate the amount equivalent to 0.08 g of phenytoin.

2. Grind the tablets, weigh out the above-calculated equivalent amount as powdered material and use directly as the test substance, dividing it into 2 equal parts.

Identity tests

Colour and other reactions

1. To 1 part of the test substance add 4 ml of ethanol (~750 g/l) TS, shake and filter. To the filtrate add 4 drops of cobalt(II) chloride (30 g/l) TS and 1 drop of ammonia (~260 g/l) TS; a blue-violet colour is produced.

2. To half of 1 part of the test substance placed on a white test plate add 2 drops of ammonia (~100 g/l) TS and 1 small drop of copper(II) sulfate (160 g/l) TS and mix thoroughly with a glass rod; a pink precipitate is produced.

PHENYTOIN SODIUM CAPSULES

Description. Each capsule usually contains 25-100 mg of phenytoin sodium.

Preparation of the sample

1. Weigh the contents of 1 capsule and calculate the amount equivalent to 0.08 g of phenytoin sodium.

2. Empty the capsules, weigh out the above-calculated equivalent amount and use directly as the test substance, dividing it into 4 equal parts.

Identity tests

Colour and other reactions

1. To 2 parts of the test substance add 4 ml of dichloromethane R and 4 drops of cobalt(II) chloride (30 g/l) TS and shake; a voluminous precipitate is produced in a blue-violet coloured solution (distinction from phenytoin).

2. Place half of 1 part of the test substance on a white test plate, add 2 drops of ammonia (~100 g/l) TS and 1 small drop of copper(II) sulfate (160 g/l) TS and mix thoroughly with a glass rod; a pink precipitate is produced.

PHYTOMENADIONE INJECTION

Description. The injection is a sterile solution usually containing 10 mg of phytomenadione in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the ampoules equivalent to 20 mg of phytomenadione; if necessary, reduce the volume by evaporation to about 2 ml or dilute to about 2 ml with water. Use directly as the test solution.

Identity tests

Colour and other reactions

1. Dilute about 1 ml of the test solution with 10 ml of ethanol (~750 g/l) TS and add 3 ml of potassium hydroxide/ethanol TS; a green colour is produced. Allow to stand for 1-2 minutes; the colour changes to blue. Again allow to stand for about 15 minutes; the colour changes to red-brown.

2. To about 1 ml of sulfuric acid (~1760 g/l) TS add 3 drops of the test solution; a brown-orange colour is produced. Heat the solution; the colour changes to dark brown.

3. To 3 drops of the test solution add 5 ml of ethanol (~750 g/l) TS and 2-5 drops of potassium permanganate (10 g/l) TS and shake; the colour of the permanganate is immediately discharged.

PIPERAZINE CITRATE SYRUP

Description. The syrup contains piperazine citrate, usually equivalent to 500 mg of piperazine hydrate in 5 ml of a suitable vehicle.

Preparation of the sample. Use the well homogenized contents of one container or the equivalent of 0.5 g of piperazine hydrate and use directly as the test solution, dividing it into 3 equal volumes.

Identity tests

Colour and other reactions

1. To 2 volumes of the test solution add 5 ml of hydrochloric acid (~70 g/l) TS and then add while stirring 1 ml of sodium nitrite (500 g/l) TS. Cool in ice for 15 minutes, stirring if necessary to induce crystallization. Filter, wash the crystals with 10 ml of ice-water and dry at 105°C; melting point, about 158°C.

2. To 1 volume of the test solution add 3 ml of calcium chloride (55 g/l) TS; no precipitate is produced. Boil the solution; a white solid is produced which is soluble in acetic acid (~300 g/l) TS.

POTASSIUM CHLORIDE SOLUTION

Description. The solution usually contains 112 mg of potassium chloride in 1.0 ml of a suitable vehicle.

Preparation of the sample

1. Pool the contents of the containers equivalent to 0.30 g of potassium chloride and use directly as test solution 1.

2. Dilute 1.0 ml of test solution 1 with sufficient water to produce 10 ml and use as test solution 2.

Identity tests

Colour and other reactions

1. Introduce test solution 1, together with hydrochloric acid (~250 g/l) TS, into a non-luminous flame using a magnesia stick or a nichrome or a platinum wire sealed to a glass rod; the flame acquires a violet colour which, when viewed through a suitable blue glass, appears reddish violet.

2. To 1.0 ml of test solution 2 add 3 ml of water and 5 drops of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash with water and add a few drops of ammonia (~100 g/l) TS; the precipitate dissolves.

3. Heat 2-3 drops of test solution 1 with a few drops of sodium hydroxide (~80 g/l) TS; no odour of ammonia is perceptible.

PROCAINE BENZYLPENICILLIN POWDER FOR INJECTION

Description. Each vial contains a sterile powder usually equivalent to 1-3 g of procaine benzylpenicillin.

Preparation of the sample

1. Weigh the contents of 1 vial and calculate the amount equivalent to 30 mg of procaine benzylpenicillin.

2. Empty the vial, weigh out the above-calculated equivalent amount and use directly as the test substance, dividing it into 6 equal parts.

Identity tests

Colour and other reactions

1. Dissolve 1 part of the test substance in 3 ml of water, add 0.1 g of hydroxylamine hydrochloride R and 1 ml of sodium hydroxide (~80 g/l) TS and allow to stand for 5 minutes. Add 1.3 ml of hydrochloric acid (~70 g/l) TS and 10 drops of ferric chloride (25 g/l) TS; a violet-red colour is produced.

2. Dissolve 1 part of the test substance in 2 ml of water and add 2-3 drops of ferric chloride (25 g/l) TS; a cream-coloured, flocculent precipitate is produced.

3. To half of 1 part of the test substance add a solution of 10 mg of paraformaldehyde R in about 1 ml of sulfuric acid (~1760 g/l) TS; an almost colourless solution is produced. Heat the solution in a water-bath for 2 minutes; a brownish violet colour is produced.

4. Dissolve 1 part of the test substance in 2 ml of water and add 5 drops of iodine TS; a brown precipitate is produced.

5. Dissolve 1 part of the test substance in 2 ml of water and add 5 drops of potassio-mercuric iodide TS; a white precipitate is produced.

6. Dissolve 1 part of the test substance in 1 ml of water and add 5 drops of hydrochloric acid (~70 g/l) TS, 10 drops of sodium nitrite (10 g/l) TS and 1 ml of sodium hydroxide (~80 g/l) TS. Then add 5 mg of 2-naphthol R; a red colour is produced.

PYRIDOXINE HYDROCHLORIDE INJECTION

Description. The injection is a sterile solution usually containing 25 mg of pyridoxine hydrochloride in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the ampoules equivalent to 0.05 g of pyridoxine hydrochloride and use directly as the test solution, dividing it into 4 equal volumes.

Identity tests

Colour and other reactions

1. Dilute 1 volume of the test solution to 2 ml with water and add 2 ml of ferric chloride (25 g/l) TS; a red-brown colour is produced. Add 4 ml of hydrochloric acid (~70 g/l) TS; the colour of the solution changes to yellow.

2. To 0.5 ml of sulfanilic acid TS add 3 drops of sodium nitrite (10 g/l) TS, 1 ml of sodium hydroxide (~80 g/l) TS and 1 volume of the test solution and allow to stand for 2 minutes; a golden yellow colour is produced. Add 2 ml of acetic acid (~300 g/l) TS; the colour remains almost the same or changes to orange.

3. Dilute 1 volume of the test solution to 2 ml with water and add 0.5 ml of nitric acid (~130 g/l) TS and 1 ml of silver nitrate (40 g/l) TS; a white precipitate is produced. Separate the precipitate, wash with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves almost completely (some excipients may interfere with the reaction).

4. To 1 volume of the test solution add 1 ml of water, 1 drop of copper(II) sulfate (160 g/l) TS and 1 ml of sodium hydroxide (~80 g/l) TS; the colour of the solution changes to deep blue.

Degradation tests

Discoloration and a change in the physical state of the test solution usually indicate gross degradation.

PYRIMETHAMINE TABLETS

Description. Each tablet usually contains 25 mg of pyrimethamine.

Preparation of the sample

1. Weigh 1 tablet and calculate the amount equivalent to 0.25 g of pyrimethamine.

2. Grind the tablets, weigh out the above-calculated equivalent amount as powdered material, shake it with 50 ml of ethanol (~750 g/l) TS heated to 60°C, filter and evaporate to dryness. Dry the residue to constant weight at 105°C and use as the test substance.

Identity tests

Melting behaviour. The test substance melts at about 239°C.

Colour and other reactions

1. Dissolve 0.05 g of the test substance in 5 ml of sulfuric acid (~100 g/l) TS and add 0.2 ml of freshly prepared potassio-mercuric iodide TS; a creamy white precipitate is produced.

2. To 1 ml of methyl orange/ethanol TS add 5 ml of water and 2 ml of ethyl acetate R and shake; the ethyl acetate layer remains colourless. Add a solution of 5 mg of the test substance dissolved in 5 ml of sulfuric acid (~5 g/l) TS, shake and allow to separate (about 30 minutes); a yellow colour is produced in the ethyl acetate layer.

3. Ignite about 0.1 g of the test substance with 0.5 g of anhydrous sodium carbonate R, cool, add 5 ml of hot water and heat in a water-bath for 5 minutes. Filter, neutralize the filtrate with nitric acid (~130 g/l) TS and add 5 drops of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

RESERPINE INJECTION

Description. The injection is a sterile solution usually containing 1 mg of reserpine in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the ampoules equivalent to 2.0 mg of reserpine and use directly as the test solution, dividing it into 4 equal volumes.

Identity tests

Colour and other reactions

1. To 1 volume of the test solution add 1 ml of dichloromethane R, shake and allow to stand. Separate the dichloromethane layer and evaporate it to dryness over a water-bath. Mix the residue with 5 mg of 4-dimethylaminobenzaldehyde R and 4 drops of glacial acetic acid R. Then add 4 drops of sulfuric acid (~1760 g/l) TS; a green colour is produced. Add about 1 ml of glacial acetic acid R; the colour changes to red.

2. To 2 volumes of the test solution add 1 drop of sulfuric acid (~100 g/l) TS and a few drops of sodium nitrite (10 g/l) TS; a yellowish green solution is produced which exhibits a greenish fluorescence.

3. To 1 volume of the test solution add a few drops of ammonium vanadate (5 g/l) TS; a green colour is produced.

SODIUM CHLORIDE INJECTION

Description. The injection is a sterile solution usually containing 9 mg of sodium chloride in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the containers equivalent to about 30 mg of sodium chloride; if necessary, reduce the volume by evaporation to about 3 ml or dilute to about 3 ml with water. Use directly as the test solution.

Identity tests

Colour and other reactions

1. Introduce a few drops of the test solution into a non-luminous flame using a magnesia stick or a nichrome or platinum wire sealed to a glass rod; the flame acquires an intense yellow colour.

2. To 2 ml of the test solution add 3 drops of nitric acid (~130 g/l) TS and 3 drops of silver nitrate (40 g/l) TS and shake; a white, curdy precipitate is produced. Separate the precipitate, wash with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

SODIUM CROMOGLICATE CAPSULES FOR INHALATION

Description. Each capsule usually contains 20 mg of sodium cromoglicate mixed with lactose in a 1:1 ratio.

Preparation of the sample

1. Weigh the contents of 1 capsule and calculate the amount equivalent to 0.06 g of sodium cromoglicate.

2. Empty the capsules, weigh out the above-calculated equivalent amount and use directly as the test substance, dividing it into 3 equal parts.

Identity tests

Colour and other reactions

1. To 1 part of the test substance add 2 ml of water and 2 ml of sodium hydroxide (~200 g/l) TS. Boil for 1 minute; a yellow solution is produced. Allow to stand for 30 minutes and add 0.5 ml of diazobenzenesulfonic acid TS2; a deep red colour is produced.

2. To 1 part of the test substance add 2 ml of potassio-cupric tartrate TS and heat; a red precipitate is produced.

3. Moisten 1 part of the test substance with 2 drops of hydrochloric acid (~70 g/l) TS and introduce the mixture into a non-luminous flame using a magnesia stick or a nichrome or platinum wire sealed to a glass rod; the flame acquires an intense yellow colour.

SODIUM HYDROGEN CARBONATE INJECTION

Description. The injection is a sterile solution usually containing 14 mg of sodium hydrogen carbonate in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the ampoules equivalent to 0.30 g of sodium hydrogen carbonate and use directly as the test solution, dividing it into 3 equal volumes.

Identity tests

Colour and other reactions

1. Introduce a few drops of the test solution into a non-luminous flame using a magnesia stick or a nichrome or platinum wire sealed to a glass rod; the flame acquires an intense yellow colour.

2. Dilute 1 volume of the test solution with 3 ml of water and add 2 drops of phenolphthalein/ethanol TS; a pink colour is produced. Heat to boiling; a colourless and odourless gas evolves and the colour of the solution changes to red-violet.

3. Dilute 1 volume of the test solution with 3 ml of water and add a few drops of magnesium sulfate (50 g/l) TS; no precipitate is produced. Boil the mixture; a white precipitate is produced.

SODIUM LACTATE INJECTION

Description. The injection is a sterile solution usually containing 500 mg of monosodium lactate in 1.0 ml of a suitable vehicle.

Preparation of the sample. Dilute a volume of the solution equivalent to 0.5 g of sodium lactate to 5 ml with water and use directly as the test solution.

Identity tests

Colour and other reactions

1. To 0.5 ml of the test solution add 2 ml of sulfuric acid (~100 g/l) TS and 3 ml of potassium permanganate (10 g/l) TS; the colour of the permanganate is discharged and an odour of acetaldehyde is perceptible.

2. To 1 ml of the test solution add 4 ml of water and mix. Add 1 ml of acetic acid (~300 g/l) TS and 1 ml of ammonium oxalate (25 g/l) TS; no precipitate is produced (distinction from calcium lactate).

3. To a few drops of the test solution add a small volume of hydrochloric acid (~250 g/l) TS and introduce the mixture into a non-luminous flame using a magnesia stick or a nichrome or platinum wire sealed to a glass rod; the flame acquires an intense yellow colour.

Alternative test:

To 5 drops of the test solution add 1 ml of water, acidify with acetic acid (~300 g/l) TS and add 2 ml of magnesium uranyl acetate TS; a light yellow, crystalline precipitate is produced.

4. To 2 ml of the test solution add, along the wall of the test-tube, 5 ml of a reagent composed of 0.10 g of catechol R dissolved in 10 ml of sulfuric acid (~1760 g/l) TS; a deep red colour is produced at the junction of the two liquids.

SULFASALAZINE TABLETS

Description. Each tablet usually contains 500 mg of sulfasalazine.1

1 Referred to as salazosulfapyridine in Basic tests for pharmaceutical substances, 1986.

Preparation of the sample

1. Weigh 1 tablet and calculate the amounts equivalent to 10 mg and 0.05 g of sulfasalazine.

2. Grind the tablets, weigh out the above-calculated equivalent amounts as powdered material and use directly, 10 mg as test substance 1 and 0.05 g as test substance 2.

Identity tests

Colour and other reactions

1. To test substance 1 add 5 ml of water, shake and filter. To the filtrate add 1 ml of sodium hydroxide (~80 g/l) TS; an orange-red to deep red colour is produced.

2. To test substance 2 add 2 drops of ethanol (~750 g/l) TS and 4 ml of hydrochloric acid (~70 g/l) TS and mix. Then add 0.2 g of zinc R powder, heat in a water-bath for 5 minutes and filter.

(a) To 1 ml of the filtrate add 4 ml of water and 2 drops of ferric chloride (25 g/l) TS; a red colour is produced.

(b) To 1 ml of the filtrate add 1 ml of sodium nitrite (10 g/l) TS and allow to stand in ice for 1 minute. Add 2 ml of sodium hydroxide (~80 g/l) TS and 2 drops of 2-naphthol TS; an intense red colour is produced.

VERAPAMIL HYDROCHLORIDE INJECTION

Description. The injection is a sterile solution usually containing 2.5 mg of verapamil hydrochloride in 1.0 ml of a suitable vehicle.

Preparation of the sample. Pool the contents of the ampoules equivalent to 15 mg of verapamil hydrochloride and use directly as the test solution, dividing it into 3 equal volumes.

Identity tests

Colour and other reactions

1. To 1 volume of the test solution add about 0.2 ml of mercuric chloride (65 g/l) TS; a white precipitate is produced.

2. To 1 volume of the test solution add 0.5 ml of sulfuric acid (~100 g/l) TS and 4 drops of potassium permanganate (10 g/l) TS; a violet precipitate is produced which immediately dissolves to produce a very pale yellow solution.

3. Acidify 1 volume of the test solution with nitric acid (~130 g/l) TS and add 2 ml of silver nitrate (40 g/l) TS; a white, curdy precipitate is produced. Separate the precipitate, wash with water and add an excess of ammonia (~100 g/l) TS; the precipitate dissolves.

Degradation tests

Discoloration and a change in the physical state of the test solution usually indicate gross degradation.

WARFARIN SODIUM TABLETS

Description. Each tablet usually contains 1-5 mg of warfarin sodium.

Preparation of the sample

1. Weigh 1 tablet and calculate the amount equivalent to 0.10 g of warfarin sodium.

2. Grind the tablets, weigh out the above-calculated equivalent amount as powdered material.

3. Extract the powdered material with two quantities, each of 15 ml, of water. Filter and to the filtrate add 2 drops of hydrochloric acid (~70 g/l) TS. Filter, wash the precipitate with water and dry at 110°C for 3 hours; melting point, about 162°C. Use the crystals as the test substance.

Identity tests

Colour and other reactions

1. Dissolve 20 mg in 1 ml of water and add 5 drops of sodium hydroxide (~80 g/l) TS and 5 drops of iodine TS; a yellow precipitate is produced and a characteristic odour of iodoform is perceptible.

2. Moisten 10 mg with 1 drop of hydrochloric acid (~70 g/l) TS and introduce the mixture into a non-luminous flame using a magnesia stick or a nichrome or platinum wire sealed to a glass rod; the flame acquires an intense yellow colour.

 

to previous section
to next section
 
 
The WHO Essential Medicines and Health Products Information Portal was designed and is maintained by Human Info NGO. Last updated: August 29, 2014