Trimipramine Tablets
Action and use
Monoamine reuptake inhibitor; tricyclic antidepressant.
Definition
Trimipramine Tablets contain Trimipramine Maleate. They are coated.
Content of trimipramine, C20H26N2
92.5 to 107.5% of the stated amount.
Identification
Triturate a quantity of the powdered tablets containing the equivalent of 0.25 g of trimipramine with 10 mL of chloroform, filter and evaporate the filtrate to low volume. Add ether until a turbidity is produced and allow to stand. The infrared absorption spectrum, Appendix II A, of the precipitate, after recrystallisation from acetone, is concordant with the reference spectrum of trimipramine maleate (RS 355).
Tests
Related substances
Carry out the method for thin-layer chromatography, Appendix III A, using silica gel G as the coating substance and a mixture of 0.7 volume of 13.5m ammonia, 10 volumes of ethanol (96%) and 90 volumes of toluene as the mobile phase. Apply separately to the plate 5 µL of each of the following solutions prepared immediately before use. For solution (1) shake a quantity of the powdered tablets containing the equivalent of 0.18 g of trimipramine with three 10 mL quantities of chloroform and filter. Evaporate the combined filtrates to dryness and dissolve the residue in 10 mL of methanol. For solution (2) dilute 1 volume of solution (1) to 200 volumes with methanol. For solution (3) dilute 2 volumes of solution (2) to 5 volumes with methanol. Solution (4) contains 0.0125% w/v of iminodibenzyl in methanol. After removal of the plate, allow it to dry in air for 15 minutes and spray with a 0.5% w/v solution of potassium dichromate in sulfuric acid (20% v/v). Examine the plate immediately. Any spot corresponding to iminodibenzyl in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (4) (0.7%, with reference to trimipramine). Any other secondary spot is not more intense than the spot in the chromatogram obtained with solution (2) (0.5%) and not more than three such spots are more intense than the spot in the chromatogram obtained with solution (3) (0.2%). Disregard any spot remaining on the line of application.
Assay
Weigh and powder 20 tablets. Shake a quantity of the powder containing the equivalent of 50 mg of trimipramine with 190 mL of a mixture of equal volumes of acetonitrile and water for 1 minute, mix with the aid of ultrasound for 5 minutes, shake for 1 minute and mix again with the aid of ultrasound for 5 minutes. Add sufficient of a mixture of equal volumes of acetonitrile and water to produce 200 mL, filter and dilute 10 mL of the filtrate to 100 mL with the same solvent. Measure the absorbance of the resulting solution at the maximum at 250 nm, Appendix II B. Calculate the content of C20H26N2 taking 320 as the value of A(1%, 1 cm) at the maximum at 250 nm.
Labelling
The quantity of active ingredient is stated in terms of the equivalent amount of trimipramine.