Polarographic and spectrophotometric determination of isocarboxazid and tranylcypromine sulphate through treatment with nitrous acid

Two methods are described for the determination of two widely prescribed antidepressants, namely isocarboxazid and tranylcypromine sulphate as the pure drugs and in dosage forms. Both methods involve prior treatment with nitrous acid. In the Spectrophotometric method, the two derivatives obey Beer's law over the concentration range 1–20 g/ml. The derivatives are polarographically reducible withE _1/2 values of –0.84 and –0.73 V for isocarboxazid and tranylcypromine sulphate, respectively. The calibration plots are linear over the range 4.3 × 10^–5–3.0 × 10^–4 and 1.1 × 10^–5–1.65 × 10^–4 mol/1 for isocarboxazid and tranylcypromine sulphate, respectively. The results obtained for assays for the two drugs compare satisfactorily with those given by the official methods.