Spectrophotometric Method for the Determination of Sulfa Drug in Pharmaceuticals Based on Charge Transfer Reaction

Khawla Salman Abd-Alrassol

Abstract

New, simple, sensitive, accurate, selective and cost effective method has been developed for the determination sulfa drugs (sulfamethoxazole and sulfamerazine) in bulk and in pharmaceutical dosage forms. The developed method , is a chemical derivatization method involving proton transfer from 2,4,6-trinitrophenol (picric acid) as Lewis acid to the secondary amino group of sulfamethoxazole and sulfamerazine as Lewis base in methanol to form a yellow charge transfer complex exhibiting maximum absorption (λ max) at 420nm and 410nm respectively. The method was linear in the concentration ranges (2-28µg/ml)and(1-30 µg/ml) with correlation coefficient (R2= 0.9992) and (R2=0.9994), to sulfamethoxazole and sulfamerazine sulfa drugs respectively .Intra-day, inter-day precision (as RSD) and accuracy were determined. The results obtained were statistically validated .The method is used to determination sulfa drugs in pharmaceutical preparations.