Validated UV spectrophotometric and HPLC methods for quantitative determination of zotepine

A high-performance liquid chromatographic method with PDA detection and UV spectrophotometric method were developed for the quantitative determination of zotepine. Chromatographic separation was achieved on a LiChrospher® RP-18 HPLC column (5 μ particle size and 25 cm × 4.6 mm internal diameter) using 0.5%trifluoroacetic acid:methanol:acetonitrile (5:40:55 v/v/v; pH 2.23) as mobile phase and aceclofenac as the internal standard. The effluent was monitored at 265 nm. Two sharp peaks were obtained for internal standard and zotepine at 3.4 and 5.1min, respectively. UV spectrophotometric method was performed at 265 nm using methanol as the solvent. Analytical performance parameters such as linearity, specificity, accuracy, precision, limit of detection and limit of quantification were determined according to International Conference on Harmonization (Q2B) guidelines. Linear range obtained was 1–10 μg mL⁻¹(r²>0.99) for HPLC method and 2.5–25 !g mL ⁻¹(r²>0.99) for UV spectrophotometric method. Validation as per ICH guidelines and statistical analysis showed that both the methods were precise, accurate, sensitive, and can be used for the routine quality control of zotepine.