Spectrophotometric determination of amitriptyline-HCI in pure and pharmaceutical preparations

Amitriptyline-HCl reacts with ammonium molybdate in concentrated sulphuric acid after heating for 20 min, at 100 degrees C to give a green colour havi ng maximum absorbance at 660 nn. The reaction is selective for amitriptylin e with 0.01 mg/10ml as visual limit of identification and provides a basis for a new spectrophotometric determination. The reaction obeys Beer's law f rom 0.01 mg to 1.4 mg/10ml of amitriptyline-HCl and the relative standard d eviation is 0.35%. The quantitative assessment of tolerable amount of other drugs is also studied.