Stability-indicating capillary zone electrophoresis assay for the analysis of linezolid in tablets

A simple and fast alternative methodology using capillary zone electrophoresis (CZE) to analyze linezolid and its cationic photodegradation products in tablets has been developed. The separation was carried out on fused silica capillary and conducted using 100 mM formic acid (pH 3.0) and by applying 30 KV voltage. Detection was performed at UV 254 nm. The optimized method was validated in terms of linearity, limits of detection and quantification, precision (repeatability), stability studies (selectivity) and accuracy. Good linearity (8-20 mg L-1) was obtained and the limit of detection was 0.95 mg L-1. The greatest advantages of the CZE method were the rapid set-up of instrumentation and capillary equilibration, short analysis time (12 min), low running cost and low waste generation. The method showed good stability in determining linezolid submitted to degradation by light and to a climatic chamber and can be used as an alternative for evaluation in stability studies of linezolid in tablets, as well as for the analysis of the drug in raw materials and finished products.