Three Simple Spectrometric Determination of Terbinafine Hydrochloride (TRB) in Pure State and Tablets

Three simple and sensitive procedures (methods A, B and C) for the assay of terbinafine hydrochloride in pure form and formulations are described. Methods A and B are based on the selective oxidation of terbinafine hydrochloride with an excess of oxidant (chloramine T) (in method A or potassium permanganate in method B) in acidic medium. The unreacted oxidant is then estimated calorimetrically by using an oxidisable dye (gallocyanine) in method A (lambda(max) 540 nm) fast green FCF in method B (lambda(max) 620 nm). Method C is based on the formation of coloured radical anion on treating terbinafine hydrochloride with 2,3 dichloro 5,6-dicyno 1,4 benzoquinone (lambda(max) 450 nm). The variable parameters in all these methods have been optimized. The results were statistically validated.