New high performance liquid chromatographic method for simultaneous determination of diclofenac and meloxicam in oral formulation of liposomes and human plasma.

Asadullah Madni; Mahmood Ahmad; Muhammad Usman; Malik Muhammad Zubair; Muhammad Qamar-Uz-Zaman; Haji Muhmmad Shoaib; Munir Abubakar; Shujat Ali Khan; Muhammad Naeem Amir; Muhammad Saleem Qureshi

A new, easy and consistent reversed-phase high-performance liquid chromatographic method with diode array detection has been developed and validated for the simultaneous determination of diclofenac potassium (DP) and meloxicam (MLX) in liposome, marketed brands and human plasma. Microextraction method based on liquid-liquid extraction principal was used to extract drug from plasma matrix. The optimized mobile phase was used in the molar ratio of 20:20:60 (v/v/v) mixture of acetonitrile, methanol and 20 x 10-3M potassium dihydrogen phosphate buffer (pH 3.7), pumped at an optimized flow rate of 1.0 mL.min-1. The linearity was performed in the concentration range of 15 ng.mL-1 to 10µg.mL-1 with r2 of 0.9989 ± 0.13 and 0.9979 ±0.11 (n=6) for DP and MLX, respectively. The assay was repeatable at concentration levels of 10 ng.mL-1, 1 µg.mL-1 and 10 µg.mL-1 with coefficient of variation of 0.168 - 0.603% for 10 ng.mL-1 (DP), 15 ng.mL-1 (MLX) and 1 µg.mL-1 &10 µg.mL-1 for DP and MLX. The LOD values were 3 and 5ng.mL−1, while values of LOQ were 10 and 15ng.mL-1, for DP and MLX. The present method is applicable in routine quality control operations, advanced drug delivery formulations (Liposomes) and in human Plasma samples for pharmacokinetics and bioequivalence studies.