Abstract
Three sensitive and accurate spectrophotometric methods were developed for the quantitative determination of sulfadoxine (SUL) and pyrimethamine (PYR) in bulk and tablet forms. Method I is based on the solvent extraction using separatory funnel, which depends on the partition of SUL and PYR in different solvents and spectrophotometric analysis of the extracts. SUL was extracted using 1M NaOH (upper layer) and PYR was extracted by CHCl3 (lower layer). The swamping method (II) is based on the presence of SUL in high amount compared to PYR (20:1). Method III is based on the simultaneous spectrophotometric determination of both drugs at 274 and 286 nm. The developed methods were validated according to ICH guidelines in terms of linearity, accuracy and precision.