Formulation development, optimization by Box-Behnken design, characterization, in vitro, ex-vivo, and in vivo evaluation of bosentan-loaded self-nanoemulsifying drug delivery system: A novel alternative dosage form for pulmonary arterial hypertension treatment

Abstract

This study aimed to develop and optimize a self-nanoemulsifying drug delivery system (SNEDDS) of bosentan (BOS) to solve its poor oral bioavailability due to low water solubility. A pseudo-ternary phase diagram was created based on the solubility and emulsification studies. The major components of the formulation were selected as glyceryl monolinoleate (lipid), polyoxyl 40 hydrogenated castor oil (surfactant), and caprylocaproyl polyoxyl-8 glycerides (co-surfactant). The composition of BOS-SNEDDS was optimized using the Box-Behnken design (BBD) and then was characterized for various physicochemical properties. The in vitro dissolution, in vitro lipolysis, and ex-vivo permeability studies were performed and compared to SNEDDS and reference tablets. The fasted and fed state bioavailability of BOS-loaded SNEDDS was evaluated in Wistar rats (n = 6) compared to the reference. The prepared SNEDDS were thermodynamically stable with a droplet size of 17.11 nm, a polydispersity index of 0.180, and an emulsification time of <1 min. The BOS-loaded SNEDDS showed 3.0, 7.97, 4.23, and 4.94-fold increases in the percentages of cumulative dissolution compared to reference tablets in FaSSIF, FeSSIF, FaSSIF-V2, and FeSSIF-V2, respectively. The permeation study showed that the SNEDDS increased the drug permeation by 3.36, 19.2, 16.4, and 16.6-fold in FaSSIF, FeSSIF, FaSSIF-V2, and FeSSIF-V2, respectively. The enhancement of in vitro dissolution, in vitro lipolysis, and ex-vivo permeability was found significant (p < 0.05). SNEDDS was increased the Cmax and AUC 1.67 and 2.12-fold and 5.15 and 1.84-fold in fasted and fed state compared to the reference, respectively. The in vitro-in vivo relationship has been successfully performed for SNEDDS. These results indicated that the SNEDDS formulation could be a promising delivery system that enhances the absorption and oral bioavailability of BOS.