Triamterene Capsules
Action and use
Sodium channel blocker; potassium-sparing diuretic.
Definition
Triamterene Capsules contain Triamterene.
Content of triamterene, C12H11N7
95.0 to 105.0% of the stated amount.
Identification
The final solution obtained in the Assay has a bluish fluorescence and the light absorption, Appendix II B, in the range 230 to 365 nm exhibits a maximum only at 360 nm.
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 90 volumes of ethyl acetate, 10 volumes of methanol and 10 volumes of 18m ammonia as the mobile phase. Apply separately to the plate 5 µL of each of the following solutions. For solution (1) dissolve a quantity of the contents of the capsules containing 0.10 g of Triamterene in sufficient dimethyl sulfoxide to produce 20 mL and dilute 2 mL to 50 mL with methanol. For solution (2) dilute 1 volume of solution (1) to 200 volumes with methanol. After removal of the plate, allow it to dry in air until the solvent has evaporated and examine under ultraviolet light (365 nm). Any secondary spot in the chromatogram obtained with solution (1) is not more intense than the spot in the chromatogram obtained with solution (2).
Assay
Dissolve a quantity of the mixed contents of 20 capsules containing 0.1 g of Triamterene in 50 mL of a mixture of equal volumes of glacial acetic acid and water with the aid of gentle heat, cool and add sufficient water to produce 500 mL. Dilute 5 mL to 200 mL with 1m acetic acid and measure the absorbance of the resulting solution at the maximum at 360 nm, Appendix II B. Calculate the content of C12H11N7 from a calibration curve prepared by treating suitable quantities of a solution of triamterene BPCRS in 1m acetic acid in the same manner and using the declared content of C12H11N7 in triamterene BPCRS.