Promethazine Teoclate Tablets
Action and use
Histamine H1 receptor antagonist; antihistamine.
Definition
Promethazine Teoclate Tablets contain Promethazine Teoclate.
Content of promethazine teoclate, C17H20N2S,C7H7ClN4O2
92.5 to 107.5% of the stated amount.
Identification
Related substances
Carry out the method for thin-layer chromatography, Appendix III A, using a silica gel F254 precoated plate (Merck silica gel 60 F254 plates are suitable) and a mixture of 5 volumes of diethylamine, 10 volumes of acetone and 85 volumes of cyclohexane as the mobile phase. Pour the mobile phase into an unlined tank, immediately place the prepared plate in the tank, close the tank and allow the solvent front to ascend 12 cm above the line of application. Apply separately to the plate 10 µL of each of the following solutions. For solution (1) shake a quantity of the powdered tablets containing 0.2 g of Promethazine Teoclate with 10 mL of a mixture of 5 volumes of diethylamine and 95 volumes of methanol for 5 minutes, filter (Whatman GF/C filter paper is suitable) and use the filtrate. Solution (2) contains 0.02% w/v of isopromethazine hydrochloride BPCRS in a mixture of 5 volumes of diethylamine and 95 volumes of methanol. For solution (3) dilute 1 volume of solution (1) to 200 volumes with a mixture of 5 volumes of diethylamine and 95 volumes of methanol. For solution (4) dilute 1 volume of solution (1) to 500 volumes with a mixture of 5 volumes of diethylamine and 95 volumes of methanol. Allow the plate to dry in air and examine under ultraviolet light (254 nm). In the chromatogram obtained with solution (1) any spot corresponding to isopromethazine hydrochloride is not more intense than the spot in the chromatogram obtained with solution (2) (1%), any other secondary spot is not more intense than the spot in the chromatogram obtained with solution (3) (0.5%) and not more than three such spots are more intense than the spot in the chromatogram obtained with solution (4) (0.2%). Disregard any spot remaining on the line of application.
Assay
Carry out the following procedure protected from light. Weigh and powder 20 tablets. To a quantity of the powder containing 50 mg of Promethazine Teoclate add 5 mL of water and 1 mL of 13.5m ammonia and allow to stand for 5 minutes. Add 50 mL of absolute ethanol, shake for 5 minutes and filter, washing the residue with five 5 mL quantities of absolute ethanol. Add sufficient absolute ethanol to the filtrate to produce 100 mL. Dilute 10 mL to 100 mL with absolute ethanol and dilute 10 mL of this dilution to 100 mL with absolute ethanol. Measure the absorbance of the resulting solution at the maximum at 255 nm, Appendix II B. Calculate the content of C17H20N2S,C7H7ClN4O2 taking 755 as the value of A(1%, 1 cm) at the maximum at 255 nm.
Storage
Promethazine Teoclate Tablets should be protected from light.