Development Green Spectrophotometric Method for Determination of Sulfamethoxazole in Pure and Pharmaceutical Formulations

Green analytical chemistry is considered as a branch of the green chemistry and the main its goal is to achieve more green analysis in quality control laboratories through different direction, such as replacing or minimizing toxic reagents and modify or replace analytical techniques or methods with safer ones. We develop a simple, accurate and sensitive spectrophotometric procedure for determination of Sulfamethoxazole (SMX) using phenoxazine (PNZ) as green analytical reagent. The method is based on oxidation in aqueous mildly acidic medium primary amine group of SMX and coupling with PNZ in the prescient iron (III) to form a stable color having maximum absorption at 520 nm. Beer's law was obeyed in the range concentration of 0.1-6 mg/l and molar absorptivity 6.105 × 104 L.mol-1.cm-1. Sandell’s sensitivity 0.003 μg.cm-2 and detection limit (DL) 0.021 ppm. The direct determination of SMX in pure form and in its pharmaceutical formulations method successfully applied with very good recoveries 98.70%-101.5%. Green spectrophotometric analytical analyses become unique when the pharmaceutical drugs reagents combine with low concentration to determinate or estimate pharmaceutical drugs.