Estropipate Tablets

General Notices

Action and use

Estrogen.

Definition

Estropipate Tablets contain Estropipate.

The tablets comply with the requirements stated under Tablets and with the following requirements.

Content of estropipate, C18H22O5S,C4H10N2

95.0 to 105.0% of the stated amount.

Identification

In the Assay, the chromatogram obtained with solution (1) shows a peak with the same retention time as the principal peak in the chromatogram obtained with solution (2).

Tests

Free estrone

Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

(1) Shake a quantity of the powdered tablets containing 5 mg of Estropipate with 20 mL of methanol (50%) for 30 minutes, centrifuge and filter the supernatant liquid.
(2) 0.0005% w/v of estrone BPCRS in methanol (50%).
chromatographic conditions
(a) Use a stainless steel column (30 cm × 3.9 mm) packed with end-capped octadecylsilyl silica gel for chromatography (10 µm) (µBondapak C18 is suitable).
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 1.5 mL per minute.
(d) Use an ambient column temperature.
(e) Use a detection wavelength of 213 nm.
(f) Inject 20 µL of each solution.
mobile phase

35 volumes of acetonitrile and 65 volumes of 0.025m potassium dihydrogen orthophosphate.

system suitability

The peak due to estrone has a retention time, relative to the peak due to estropipate, of about 5.

limits

In the chromatogram obtained with solution (1):

the area of any peak corresponding to estrone is not greater than the area of the peak in the chromatogram obtained with solution (2) (2%).

Uniformity of content

Tablets containing less than 2 mg and/or less than 2% w/w of Estropipate comply with the requirements stated under Tablets using the following method of analysis. Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

(1) Add 20 mL of water to one tablet and shake for 30 minutes, add 20 mL of methanol to the mixture and shake for a further 30 minutes, dilute to 50 mL with methanol (50%) and filter. Dilute 10 mL of the filtrate to 20 mL with methanol (50%).
(2) 0.0015% w/v of estropipate BPCRS in methanol (50%).
chromatographic conditions

The chromatographic procedure described under Free estrone may be used.

determination of content

Calculate the content of C18H22O5S,C4H10N2 in each tablet using the declared content of C18H22O5S,C4H10N2 in estropipate BPCRS.

Assay

Weigh and powder 20 tablets. Carry out the method for liquid chromatography, Appendix III D, using the following solutions.

(1) Shake a quantity of the powdered tablets containing 3 mg of Estropipate with 40 mL of methanol (50%) for 30 minutes, dilute to 100 mL with the same solvent and filter.
(2) 0.003% w/v of estropipate BPCRS in methanol (50%).
chromatographic conditions

The chromatographic procedure described under Free estrone may be used.

determination of content

Calculate the content of C18H22O5S,C4H10N2 in the tablets using the declared content of C18H22O5S,C4H10N2 in estropipate BPCRS.