Labetalol Tablets
Action and use
Alpha- and beta-adrenoceptor antagonist.
Definition
Labetalol Tablets contain Labetalol Hydrochloride.
Content of labetalol hydrochloride, C19H24N2O3,HCl
95.0 to 105.0% of the stated amount.
Identification
Tests
Related substances
Carry out the method for thin-layer chromatography, Appendix III A, using the following solutions.
5 volumes of 13.5m ammonia, 25 volumes of methanol and 75 volumes of dichloromethane.
Any secondary spot in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2) (1%) and not more than one such spot is more intense than the spot in the chromatogram obtained with solution (3) (0.5%).
Assay
Weigh and powder 20 tablets. Shake a quantity of the powdered tablets containing 1 g of Labetalol Hydrochloride with 250 mL of 0.05m sulfuric acid for 30 minutes. Dilute the mixture to 500 mL with 0.05m sulfuric acid, mix, filter and dilute 10 mL of the filtrate to 250 mL with 0.05m sulfuric acid. Measure the absorbance of the resulting solution at the maximum at 302 nm, Appendix II B. Calculate the content of C19H24N2O3,HCl taking 86 as the value of A(1%, 1 cm) at the maximum at 302 nm.