Valsartan Loaded Solid Self-Nanoemulsifying Delivery System to Enhance Oral Absorption and Bioavailability

Abstract

Valsartan (VST) is an angiotensin II receptor antagonist with low oral bioavailability. The present study developed a solid self-nanoemulsifying drug delivery system (S-SNEDDS) to enhance the oral absorption and bioavailability of VST. VST-loaded liquid SNEDDS (VST@L-SNEDDS) was prepared by investigating the solubility of VST and constructing the pseudo-ternary phase diagrams. The formulation of VST@S-SNEDDS was obtained by adsorbing VST@L-SNEDDS onto a solid carrier. In vitro studies including drug dissolution, stability, cytotoxicity, and Caco-2 uptake of VST@S-SNEDDS were assessed. An in vivo pharmacokinetic study of VST@S-SNEDDS was employed to evaluate the oral bioavailability of VST. VST@L-SNEDDS, with an average particle size of 19.90 nm and zeta potential of -20.57 mV, consisted of 12.37% VST (drug loading), 21.91% ethyl oleate, 45.50% RH 40, and 20.22% Transcutol HP. VST@S-SNEDDS was prepared using Neusilin® UFL2 as a solid adsorbent, which contained VST@L-SNEDDS at 2.28 ± 0.15 g/g. The in vitro release study demonstrated that VST@S-SNEDDS exhibited rapid release characteristic without affecting by the pH of the media, and dissolution rates exceeded 90% within 60 min in different media. The long-term stability of VST@S-SNEDDS was better than that of VST@L-SNEDDS. These two formulations increased the Caco-2 uptake significantly. The area under the drug concentration–time curve (AUC_0-24h) and peak drug concentration in plasma (C_max) of VST@S-SNEDDS increased by 2.28-fold and 4.86-fold compared to raw VST, respectively. The proposed VST@S-SNEDDS represents a novel approach to enhance the oral absorption and bioavailability of VST, providing a promising avenue for hypertension treatment.

Graphical Abstract