Promethazine Hydrochloride Tablets
Action and use
Histamine H1 receptor antagonist; antihistamine.
Definition
Promethazine Hydrochloride Tablets contain Promethazine Hydrochloride. They are coated.
Content of promethazine hydrochloride, C17H20N2S,HCl
95.0 to 105.0% of the stated amount.
Identification
Related substances
Carry out the test for related substances in phenothiazines, Appendix III A, using mobile phase B and applying separately to the plate 20 µL of each of the following freshly prepared solutions. For solution (1) extract a quantity of the powdered tablets containing 0.1 g of Promethazine Hydrochloride with 10 mL of a mixture of 95 volumes of methanol and 5 volumes of diethylamine and filter. Solution (2) contains 0.010% w/v of isopromethazine hydrochloride BPCRS in the same solvent. For solution (3) dilute 1 volume of solution (1) to 200 volumes with the same solvent. Any spot corresponding to isopromethazine in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2) (1%) and any other secondary spot is not more intense than the spot in the chromatogram obtained with solution (3) (0.5%).
Assay
Carry out the following procedure protected from light. Weigh and powder 20 tablets. Triturate a quantity of the powder containing 50 mg of Promethazine Hydrochloride with 10 mL of 2m hydrochloric acid and add 200 mL of water. Shake for 15 minutes, add sufficient water to produce 500 mL and centrifuge about 50 mL of the mixture. To 5 mL of the clear, supernatant liquid add 10 mL of 0.1m hydrochloric acid and sufficient water to produce 100 mL. Measure the absorbance of the resulting solution at the maximum at 249 nm, Appendix II B. Calculate the content of C17H20N2S,HCl taking 910 as the value of A(1%, 1 cm) at the maximum at 249 nm.