Stability of Oral Oxytocics in Tropical Climates - Results of Simulation Studies on Oral Ergometrine, Oral Methylergometrine, Buccal Oxytocin and Buccal Desamino-Oxytocin - EDM Research Series No. 012
(1994; 52 pages) View the PDF document
Table of Contents
View the documentAbbreviations
View the documentSummary
Open this folder and view contentsIntroduction
Close this folderMaterials and methods
View the documentDefinitions used in the study
View the documentSimulated tropical conditions
View the documentMaterials
View the documentAssay method
View the documentStatistics
Open this folder and view contentsResults
Open this folder and view contentsDiscussion
View the documentConclusions and recommendations
View the documentReferences
Open this folder and view contentsAnnexes
 

Assay method

Level of active ingredient was measured by High Performance/Pressure Liquid Chromatography (HPLC). This method can differentiate between the active principle and its degradation products. The Radio Immuno Assay, another assay method, is unable to make this distinction. However, this latter method is more sensitive than the HPLC assay (15,21-27).

HPLC-conditions: ergometrine and methylergometrine

Column:

Spherisorb 5 ODS (250*4.6 mm) chrompack (Bergen op Zoom, Netherlands)

Mobile phase:

A = acetonitrile

 

B = 0.067 M KH2SO4: 0.05% diethylamine H2O

 

A = 60%; B = 40%; (1:1)

Wavelength:

UV: 240 nm

Flow:

1.2 ml/min

Injection volume:

100 ml

Retention time:

6.8 min

Reference solutions:

Freshly made before each new set of runs, with increasing concentrations from solution I to IV

Apparatus:

SP8800 ternary HPLC pump, a Spectra Physics UV detector 757 and an SP 4290 integrator (Spectra Physics)

Calibration curves

Ergometrine:

r = 0.9999

 

Methylergometrine:

r = 0.9999

Table III: Inter-day and intra-day coefficients of variation of (methyl)ergometrine in water

Compound

Coefficient of variation (n =4/6) (%)

 

Concentration of free base (mg/tablet)

Inter-day (n=4)

Intra-day (n=6)

Ergometrine

147

1.2

1.73

Methyl- ergometrine

95

2.2

5.07

HPLC-conditions: oxytocin and desamino-oxytocin

Column:

Spherisorb 5.0 ODS(250*4.6mm) chromopack

Mobile phase:

A: acetonitrile/H2O 1:1

 

B: 0.1 M monobasicKH2PO4

 

buffer A = 55% ; B = 45%

Wavelength:

UV: 225 nm

Flow:

1.2 ml/min

Injection volume:

100 ml

Retention time:

6.7 min

Reference solutions:

Freshly made before each new set of runs, with increasing concentrations from solution I to IV.

Apparatus:

SP8800 ternary HPLC pump, a UV detector 757 and an SP 4290 integrator (Spectra Physics).

Calibration curves:

Oxytocin:

r = 0.9999

 

Desamino-oxytocin:

r = 0.9999

Table IV: Inter-day and intra-day coefficients of variation of desamino-oxytocin in water

C Compound

Coefficient of variation (n =4/6) (%)

 

Concentration (IU/tablet)

Inter-day (n=4)

Intra-day (n=6)

Oxytocin

200

1.90

2.06

Desamino- oxytocin

50

3.19

1.96

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