Formulation, Development, and Evaluation of Bosentan Monohydrate Spray Dried- Solid Dispersion Tablets for Improved Dissolution Profile

Abstract

Bosentan monohydrate (BM) is utilized for the treatment of pulmonary arterial hypertension, exhibiting poor aqueous solubility and bioavailability. This study aims to enhance the dissolution rate of the drug using Eudragit®EPO through spray drying. The drug and Eudragit®EPO were combined in ratios of 1:1, 1:2, 1:3, 1:4, and 1:5 (w/w) to generate compositions SD1 to SD5. SD5, at a 1:5 drug-to-carrier ratio, demonstrated a statistically significant increase in saturation solubility and drug content. Six tablet formulations (F1 to F6) containing SD5 and tableting excipients were developed and processed. Formulation F2, consisting of 26.36% HPMC K4M and 23.63% MCC, exhibited the highest dissolution and drug release. The probable mechanism underlying BM dissolution in SD involves its amorphous form and the solubilizing effect facilitated by hydrogen bonding between BM and Eudragit®EPO. The carrier's binding effect likely contributed to high tensile strength, low friability, and extended disintegration time. Direct mixing of SD with HPMC might have improved the uniformity of SD within the tablet matrix and the release profile. This study demonstrates the efficacy of spray drying in preparing SD of BM with Eudragit®EPO, potentially enhancing its solubility and stability.