A new Hplc approach for determination of in-vitro solubility of naproxen sodium

Naproxen sodium (NAS) is a non-steroidal anti-inflammatory drug commonly used for the reduction of moderate to severe aches and pains. This study presents a simple and sensitive high-performance liquid chromatographic method for the determination of in-vitro solubility of NAS. Chromatographic separation of NAS was achieved on a reversed-phase column (Waters Spherisorb S10 ODS2 C₁₈ 200x4.6 mm column) with the mobile phase consisted of 0.05M phosphate buffer (pH 4.0), methanol and acetonitrile (50:20:30 v/v), at a flow rate 1 mL.min^-1. Chromatographic detection of NAS was performed at 230 nm with UV detector system. The retention time was about 7 min. Calibration curve was linear over the concentration range of 5-150 μg.mL^-1. The limit of quantitation was found to be 78 ng.mL^-1. The intra- and inter-day precision relative standard deviation was 3.7% or less, and the accuracy was within 5.4% deviation of the nominal concentration. The proposed HPLC method was successfully applied to the analysis of NAS solubility.