Alimemazine Tablets

General Notices

Action and use

Histamine H1 receptor antagonist; antihistamine.

Definition

Alimemazine Tablets contain Alimemazine Tartrate.

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

Content of alimemazine tartrate, C36H44N4S2,C4H6O6

92.5 to 107.5% of the stated amount.

Identification

A. To a quantity of the powdered tablets containing 40 mg of Alimemazine Tartrate add 10 mL of water and 2 mL of 1m sodium hydroxide, shake and extract with 15 mL of ether. Wash the ether layer with 5 mL of water, dry with anhydrous sodium sulfate and evaporate the ether to dryness. Dissolve the residue in 0.4 mL of dichloromethane. The infrared absorption spectrum of the resulting solution, Appendix II A, is concordant with the reference spectrum of alimemazine (RS 005).
B. To a quantity of the powdered tablets containing 1 mg of Alimemazine Tartrate add 1 mL of a mixture of equal volumes of formaldehyde solution and sulfuric acid. A purple colour is produced.

Tests

Related substances

Comply with the test for related substances in phenothiazines, Appendix III A, using mobile phase A 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 Alimemazine Tartrate with 10 mL of a mixture of 95 volumes of methanol and 5 volumes of diethylamine and filter. For solution (2) dilute 1 volume of solution (1) to 200 volumes with the same solvent mixture.

Assay

Carry out the following procedure protected from light. Add 150 mL of 0.1m hydrochloric acid to 10 tablets, shake for 10 minutes, mix with the aid of ultrasound for 1 minute, dilute with 0.1m hydrochloric acid to produce a solution containing 0.050% w/v of Alimemazine Tartrate and filter (solution A). Dilute 10 mL of solution A to 100 mL with water (solution B). To a further 10 mL of solution A add 2 mL of peroxyacetic acid solution, mix, allow to stand for 5 minutes and add sufficient water to produce 100 mL (solution C). Measure the absorbance of solution C at the maximum at 342 nm, Appendix II B, using solution B in the reference cell and measure the absorbance of solution B at the same wavelength using water in the reference cell. Repeat the procedure using a 0.05% w/v solution of alimemazine tartrate BPCRS in 0.1m hydrochloric acid in place of solution A, beginning at the words ‘Dilute 10 mL of solution A ...’ and calculate the content of C36H44N4S2,C4H6O using the declared content of C36H44N4S2,C4H6O in alimemazine tartrate BPCRS. The test is not valid if the absorbance of solution B is more than 0.10.