Stability-indicating assay of mequitazine in bulk and pharmaceutical tablets

Simple and selective spectrophotometric procedures for the determination of mequitazine in its pharmaceutical tablets are described. The method was based on the formation of complex between mequitazine and palladium in presence of methyl cellulose in buffered or unbuffered media. The two procedures provide a mean of following the oxidative decomposition of the investigated drug. The apparent molar absorptivities at 460 and 500 nm were 2810 and 2840 and with Sandell's sensitivity of 0.116 and 0.103 for the buffered and unbuffered solutions, respectively. At the same time, Beer's law was obeyed in a concentration range of 2.4-7.2 mg% and the regression line equations were derived with correlation coefficients of 0.9997 and 0.9999 for buffered and unbuffered reactions, respectively. The validity of the method was further confirmed using the standard addition method. The proposed procedures demonstrate high percentage of recovery with good accuracy and precision.