Enhancing lymphatic uptake of Darunavir Ethanolate through TPGS-enriched lipid nanocarriers for oral delivery

Abstract

Darunavir ethanolate (DRVE) is a promising molecule against wild-type protease inhibitors in human immunodeficiency virus (HIV) infection. It has a 37% oral bioavailability. In this study, the d-alpha-Tocopheryl Polyethylene Glycol 1000 Succinate (TPGS)-decorated DRVE-loaded lipid nanocarriers (DRVE-TPGS-LNCs) were optimized via central composite rotatable design using a modified solvent emulsification method. Various characteristic features of DRVE-TPGS-LNCs, such as globule size, polydispersity index, zeta potential, % entrapment efficiency, and % drug loading, were determined and found to be 116.5 ± 2.52 nm, 0.269 ± 0.0221, −10.8 ± 0.265 mV, 94.31% ± 10.75%, and 8.79% ± 0.937%, respectively. The spherical shape was evaluated by cryo-transmission electron microscopy. In-vitro study demonstrated % cumulative drug release of 81.70% ± 7.35% at pH 1.2 and 73.03% ± 7.17% at pH 6.8 after 12 h of drug release study. Moreover, the intestinal permeation and confocal microscope studies revealed approximately two-fold increased permeation in optimized nanoformulation across the gut sac compared to a drug suspension, and the inhibition of p-glycoprotein efflux was also confirmed by obtaining a minimum efflux ratio (0.253) of the optimized formulation compared to a drug suspension. The pharmacokinetic study demonstrated that the relative bioavailability of TPGS-DRVE-LNCs and drug suspension were found to be 19.85 ± 1.75 and 8.72 ± 0.753 μg.h/mL, respectively, which is approximately 2.25-fold more than the drug suspension which means approximately threefold increase in oral bioavailability compared to the drug suspension. The increased bioavailability in optimized DRVE-TPGS-LNCs was due to improved lymphatic uptake and p-glycoprotein efflux inhibition. Thus, the improved bioavailability of DRVE can meet the need to reduce the high dose of antiretroviral drugs to minimize the peripheral adverse reactions associated with the dose-related burden.