Analysis of amoxycillin in capsules and oral suspensions by high-performance liquid chromatography

Abstract

A method has been developed for assay of amoxycillin (AMX) from pharmaceutical preparations which is an advance on previously published methods. It makes use of an isocratic HPLC system. The chromatographic conditions comprised a reversed-phase C₁₈ column (100 mm × 2 mm) with a mobile phase of methanol–50 mmol l^–1 aqueous phosphate buffer (3 + 97) at pH 7.0 pumped at 0.4 ml min^–1. Ultraviolet detection was at 230 nm and a photodiode array detector was used for examination of peak homogeneity. The method involves a simple sample pre-treatment stage for capsules and oral suspension formulations and has been validated (for linearity, accuracy, precision and specificity) according to current guidelines. The two major starting materials used in the synthesis of AMX can be detected and the method has been shown to indicate stability. The method was used to assay AMX capsule and oral suspension samples from Nigeria and Thailand as part of a larger study investigating the quality of pharmaceuticals in developing countries. From these analyses sub-standard AMX preparations were found from both countries.