Enhanced solubility and permeability of exemestane solid dispersion powders for improved oral delivery

The aim of the present investigation was to enhance the solubility of exemestane (EXM), by solid dispersion (SD) technique using PEG 6000 as a carrier. Phase solubility studies were conducted with PEG 6000 and PEG 20000 to evaluate the effect of carriers on aqueous solubility of EXM. The aqueous solubility of EXM was favoured with PEG 6000 compared to PEG 20000. SDs of EXM using polyethylene glycol 6000 (PEG 6000) as carrier were prepared in different drug to carrier ratios. Solid-state characterization indicated decrease in crystallinity of the drug. The in vitro dissolution rate of EXM was enhanced from both SDs and tablet formulations prepared using SD compared to pure EXM. The in situ permeability studies investigated using single-pass intestinal perfusion technique in rats revealed increase in effective intestinal permeability (P_eff, cm/s) by 4.45 folds with SDs. Thus, EXM-PEG 6000 SDs showed improved solubility and permeability.