Sensitive and Selective Spectrophotometric Methods for the Determination of Cisaprid, Metoclopramide Hydrochloride, Sulphadoxine and Sulphamethoxazole

Two simple, sensitive and selective spectrophotometric methods were developed for the determination of cisapride (CPD), metoclopramide hydrochloride (MCP), sulphadoxine (SDX) and sulphamethoxazole (SMX) containing aromatic primary amino group. The methods are based on the interaction of diazotised drugs with iminodibenzyl (IDB) and 3-chloroiminodibenzyl (Cl-IDB) (new spectrophotometric reagents) in hydrochloric acid medium to yield violet or red colored product with maximum absorption at 570 or 500 nm, respectively. The commonly encountered excipients and additives along with the drug do not interfere with the determination. These drugs can be determined in the range of 0.2-8.0 g/mL, with a maximum relative standard deviation of 1.10% and 1.40% for IDB and Cl-IDB, respectively. Results of the analysis of some preformulations and commercial tablets (Perinorm, Amalar and Bactrim DS for MCP, SDX and SMX respectively) by these methods agree well with those determined by the official methods.