RP‐HPLC Method Development for Simultaneous Determination of Mesalamine and Quercetin in Pure Forms and in Solid Lipid Nanoparticle Formulations

ABSTRACT This study aimed to develop and validate a straightforward HPLC method for simultaneously estimating mesalamine and quercetin in both pure forms and solid lipid nanoparticle formulations. Following International Council for Harmonisation Q2(R2) guidelines, the analytical method was validated. Furthermore, this optimized method was applied to measure the percentage entrapment efficiency and in vitro drug release in central composite design‐based optimized solid lipid nanoparticle formulations. The chromatogram showed the peak of mesalamine and quercetin at retention times of 2.28 and 8.79 min, respectively. For mesalamine, limits of detection and quantification were found to be 1.64 and 4.97 µg/mL, respectively. Whereas for quercetin, limits of detection were 2.10 µg/mL and limit of quantification was 6.36 µg/mL, respectively. The entrapment efficiency of mesalamine and quercetin in solid lipid nanoparticles was 85.27 ± 1.74% and 78.62 ± 2.38%, respectively. Furthermore, the in vitro drug release study indicated 98.83 ± 2.94% release of mesalamine and 96.56 ± 1.92% release of quercetin from solid lipid nanoparticles over 24 h. The results demonstrated that the HPLC method developed was accurate, precise, and robust, maintaining its reliability despite minor changes in flow rate and wavelength. Consequently, this method was suitable for estimating mesalamine and quercetin in various formulations.