Monographs: Pharmaceutical substances: Podophyllum resin (Podophylli resina)

Chemical name. Podophyllum resin; CAS Reg. No. 8050-60-0.

Other name. Podophyllinum.

Description. Light brown to greenish yellow or brownish grey masses or an amorphous powder.

Solubility. Practically insoluble in cold water; partially soluble in hot water, and ether R; soluble in ethanol (~750 g/l) TS.

Category. Keratolytic agent.

Storage. Podophyllum resin should be kept in a tightly closed container, protected from light, and preferably stored at a temperature between 2 and 15 °C.

Labelling. The designation on the container should state the botanical source.

Additional information. CAUTION: Podophyllum resin must be handled with care, avoiding contact with the skin and mucous membranes and inhalation of airborne particles.

On exposure to light or to temperatures above 25 °C, it becomes darker in colour.

Requirements

Definition. Podophyllum resin is a mixture of resins obtained from the rhizomes and roots of Podophyllum hexandrum Royle (P. emodi Wall.) or Podophyllum peltatum L. after percolation with ethanol and precipitation from water or very dilute acids.

Podophyllum resin contains not less than 40.0% and not more than the equivalent of 52.5% of podophyllum toxin (α and β peltatum), calculated with reference to the dried substance.

Identity tests

A. Dissolve 10 mg in 2 mL of ethanol (~750 g/l) TS and add 1 drop of ferric chloride (25 g/l) TS; a deep, dark green colour is produced and the solution appears black in reflected light.

B. Add 0.4 g, finely powdered, to 3 mL of ethanol (~535 g/l) TS, then add 0.5 mL of potassium hydroxide (1 mol/l) VS, shake gently, and allow to stand; the resin of P. hexandrum produces a stiff jelly, whereas the resin of P. peltatum does not gelatinize.

C. To two separate tubes add a few mg of Podophyllum resin, add potassium hydroxide (1 mol/l) VS to one tube and sodium hydroxide (1 mol/l) VS to the other, and allow to dissolve; a yellow solution is produced in both tubes which becomes darker on standing. Add a few drops of hydrochloric acid (~250 g/l) TS; a resin precipitates.

Matter insoluble in ethanol. Shake 1 g, finely powdered, with 20 mL of ethanol (~750 g/l) TS for 5 minutes. Filter through a sintered-glass crucible (approx. porosity 40 μm), wash the filter with ethanol (~750 g/l) TS, and dry at 105 °C; the residue weighs not more than 25 mg.

Matter insoluble in ammonia. Shake 0.5 g, finely powdered, with 30 mL of ammonia (~100 g/l) TS for 30 minutes at about 20 °C. Filter through a sintered-glass crucible (approx. porosity 40 μm) and wash the flask and filter with 30 mL of water, the time taken for filtering and washing being not more than 10 minutes. Dry the filter with the residue to constant mass at 105 °C; the residue from the resin of P. hexandrum weighs not less than 0.18 g and not more than 0.30 g, whereas the residue from the resin of P. peltatum weighs not more than 50 mg.

Sulfated ash. Not more than 15 mg/g.

Loss on drying. Dry to constant mass at 105 °C; it loses not more than 50 mg/g.

Assay. Transfer about 0.45 g, finely powdered and accurately weighed, to a glass-stoppered 50-mL flask, add 15 mL of chloroform R, and shake for 30 minutes. Filter, then transfer 10 mL of the filtrate to a tared 100-mL flask, previously dried to constant mass at 70 °C and containing 80 mL of light petroleum R. Filter the precipitate through a tared sintered-glass crucible (approx. porosity 40 μm), previously dried to constant mass at 70 °C, and wash the flask and the filter with 20 mL of light petroleum R. Dry both of them at 70 °C for 1 hour, cool, and weigh. Determine the mass of the residue, taking into account the tare of the filter and the flask.

Each g of residue is equivalent to 0.30 g of Podophyllum resin.

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