Freeze dried solid dispersion of exemestane: A way to negate an aqueous solubility and oral bioavailability problems
This study was envisaged to demonstrate the potential of exemestane loaded phospholipid/sodium deoxycholate solid dispersions (EXE-PL/SDC-SDs) on the solubility and oral bioavailability of EXE. Initial studies were performed to screen the best suitable phospholipid among lysophosphatidylcholine, Phospholipon® P80H and Lipoid® E80S for solid dispersion preparation. Further studies were carried out to optimize the molar concentration of phospholipid and sodium deoxycholate (SDC) for EXE-PL/SDC-SDs preparation. Optimized EXE-PL/SDC-SDs was prepared using Lipoid® E80S and SDC in 1:4 M concentration, respectively and lyophilized using 10% w/w 2-hydroxypropyl-β-cyclodextrin (2-HPCD). The physical state of EXE in lyophilized formulation was confirmed by DSC and PXRD. Lyophilized formulation exhibits a significant increase in solubility and dissolution rate as compared to free drug EXE. Apparent permeability study was performed on Caco-2 cell line for 2 h. The lyophilized EXE-PL/SDC-SDs exhibits 4.6-fold increase in absorptive transport as compared to EXE. Pharmacokinetic study in fasted female Sprague-Dawley rats revealed a 2.3-fold increase in AUC0-72h. Thus, the results suggest that PL/SDC-SDs is a promising carrier for EXE delivery.