Action and use
Angiotensin converting enzyme inhibitor.
Definition
Captopril Tablets contain Captopril.
The tablets comply with the requirements stated under Tablets and with the following requirements.
Content of captopril, C9H15NO3S
95.0 to 105.0% of the stated amount.
Identification
A. Dissolve a quantity of the powdered tablets containing 0.1 g of Captopril in 25 mL of
methanol with the aid of ultrasound and filter. Mix 1 mL of the filtrate with 0.5 g of
potassium bromide, dry at room temperature at 2 kPa, grind to a uniform mixture and prepare a disc. The
infrared absorption spectrum,
Appendix II A, is concordant with the
reference spectrum of captopril
(RS 038).
B. In the Assay, the principal peak in the chromatogram obtained with solution (1) has the same retention time as the peak due to captopril in the chromatogram obtained with solution (2).
Tests
Captopril disulfide
Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1) Transfer a quantity of the powdered tablets containing 25 mg of Captopril to a centrifuge tube, add 25 mL of
methanol, centrifuge for 15 minutes and use the supernatant liquid.
(2) 0.0030% w/v of
captopril disulfide BPCRS in
methanol.
(3) Dilute 1 volume of solution (1) to 100 volumes with solution (2).
chromatographic conditions
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 1 mL per minute.
(d) Use an ambient column temperature.
(e) Use a detection wavelength of 220 nm.
(f) Inject 20 µL of each solution.
mobile phase
0.5 volume of orthophosphoric acid, 450 volumes of water and 550 volumes of methanol.
system suitability
The test is not valid unless, in the chromatogram obtained with solution (3), the resolution factor between the peaks due to captopril and captopril disulfide is at least 2.0.
limits
In the chromatogram obtained with solution (1) the area of any peak corresponding to captopril disulfide is not greater than the area of the peak in the chromatogram obtained with solution (2) (3%).
Assay
Weigh and powder 20 tablets. Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
(1) Transfer a quantity of the powdered tablets containing 25 mg of Captopril to a centrifuge tube, add 25 mL of the mobile phase, mix with the aid of ultrasound for 15 minutes and centrifuge. Dilute 1 volume of the supernatant liquid to 10 volumes with the mobile phase.
(2) 0.01% w/v of
captopril BPCRS and 0.0005% w/v of
captopril disulfide BPCRS in the mobile phase.
chromatographic conditions
The chromatographic conditions described under Related substances may be used.
system suitability
The test is not valid unless, in the chromatogram obtained with solution (2), the resolution factor between the peaks due to captopril and captopril disulfide is at least 2.0.
determination of content
Calculate the content of C9H15NO3S in the tablets using the declared content of C9H15NO3S in captopril BPCRS.