Modified Simplex - Spectrophotometric Determination of Clonazepam via Charge-Transfer Complexation

A simple, sensitive, accurate, and precise spectrophotometric method for thedetermination of clonazepam (CLNZ) was developed. The method is based on charge transferreaction between CLNZ and p-Bromanil (p-Br) to form a colored complex. The optimumconditions of complex formation were investigated by (1). Unvariable method, for theoptimization of reagent concentration, base concentration, temperature, and time. (2).Multivariable simplex method including the effect of three experimental factors via; reagent concentration, concentration of NaOH and time. The linearity range of CLNZ was (1-30) μg.mL-1 at 378 nm under condition established via simplex method with molar absorptivity (1.9069x104) L.mol-1.cm-1, Sandell s sensitivity index (0.0165) μg.cm-2, detection limit of 0.2957μg.mL-1, quantification limit 0.9858μg.mL-1 and association constant of the formed complex (2333.3). The proposed method has been successfully applied for the determination of CLNZ in pure form and pharmaceutical preparations.