Determination of loratadine in human plasma by high-performance liquid chromatographic method with ultraviolet detection.

A HPLC-UV determination of loratadine in human plasma is presented. After simple liquid-liquid extraction with 2-methylbutane-hexane (2:1) and evaporation of organic phase the compounds were re-dissolved in 0.01 M HCl, evaporated again and finally separated on a Supelcosil LC-18-DB column. The analyses were done at ambient temperature under isocratic conditions using the mobile phase: CH3CN-water-0.5 M KH2PO4-H3PO4 (440:480:80:1, v/v). UV detection was performed at 200 nm with a limit of quantification of 0.5 ng/ml. The precision was found to be satisfactory over the whole range tested (0.5-50 ng/ml) with relative standard deviations of 2.3-6.3 and 5.2-14.1% for intra- and inter-assays, respectively.