Development and validation of reverse-phase high-performance liquid chromatographic (RP-HPLC) method for quantification of Efavirenz in Efavirenz-Enfuvirtide co-loaded polymer-lipid hybrid nanoparticles.

The objective of present work was to develop rapid, sensitive, selective, accurate and precise RP-HPLC method for analysis of Efavirenz from combination anti-HIV drug (Efavirenz-Enfuvirtide) incorporated into polymer-lipid hybrid nanoparticles (PLN). Chromatographic separation of Efavirenz was performed on Waters Spherisorb® 5 μm ODS (C18) column (4.6 x 250 mm) with acetonitrile and 10 mM phosphate buffer pH 6.8 (70:30, v/v) as mobile phase. The UV detection wavelength was 246 nm. The method was found to be linear between the concentration range of 500-20000 ng/ml with 160 ng/ml and 480 ng/ml as limit of detection and limit of quantitation respectively. Heteroscedasticity of calibration curve responses was minimized using weighted least square regression analysis. The method was found to be specific for analysis of Efavirenz in presence of Enfuvirtide (a fusion inhibitor peptide), formulation excipients and release media, accurate (average recovery rate: 99.9 ± 9.39%) and precise (%RSD < 2%). The validated RP-HPLC method could be effectively utilized to determine % entrapment efficiency (%EE), % drug loading (%DL), % cumulative drug release and drug content of Efavirenz from Efavirenz-Enfuvirtide co-loaded PLN.