Preparation and evaluation of valsartan by a novel semi-solid self-microemulsifying delivery system using Gelucire 44/14

The aim of the present study was to develop a novel semi-solid self-microemulsifying drug delivery system (SMEDDS) using Gelucire^® 44/14 as oil with strong solid character to improve the oral bioavailability of poorly soluble drug valsartan. The solubility of valsartan in various excipients was determined, the pseudo-ternary phase diagram was constructed in order to screen the optimal excipients, and DSC analysis was performed to evaluate the melting point of SMEDDS. The optimal drug-loaded SMEDDS formulation was consisted of 30% Gelucire^® 44/14 (oil), 40% Solutol^® HS 15 (surfactant), and 30% Transcutol^® P (cosurfactant) (w/w) with 80?mg valsartan/g excipients. The average droplet sizes of the optimized blank and drug-loaded SMEDDS formulations were 26.20?±?1.43 and 33.34?±?2.15?nm, and the melting points of them were 35.6 and 36.8?°C, respectively. The in vitro dissolution rate of optimal semi-solid SMEDDS was increased compared with commercial capsules, resulting in the 2.72-fold and 2.97-fold enhancement of C_max and AUC_0–t after oral administration in rats, respectively. These results indicated that the novel semi-solid SMEDDS formulation could potentially improve the oral bioavailability of valsartan, and the semi-solid SMEDDS was a desirable system than the traditional liquid SMEDDS because it was convenient for preparation, storage and transportation due to semi-solid state at room temperature and melted state at body temperature.