Improving the Dissolution and Oral Bioavailability of the Poorly Water-soluble Drug Aloe-Emodin by Solid Dispersion With Polyethylene Glycol 6000

Solid dispersions (SDs) of aloe-emodin (AE) and polyethylene glycol 6000 (PEG6000) with different drug loadings were prepared, characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSc) and evaluated for solubility and in vitro release. The oral bioavailability of AE from SD in rats was compared with the crystalline drug. Plasma concentrations of AE were determined by HPLC. After administration of crystalline AE (35 mg . kg(-1)) in rats, the AUC(0-600) and C-max were 393.6 +/- 77.1 mg.min.l(-1) and 1.87 +/- 0.30 mg.l(-1), respectively. For the PEG6000 SD of AE, AUC(0-600) and C-max were boosted to 1310.5 +/- 111.9 mg.l(-1) and 5.86 +/- 0.47 mg.l(-1), respectively. The results indicated that the oral bioavailability of AE was increased significantly. Simultaneously, the T-max value of AE for AE crystalline was decreased from 75.6 +/- 17.3 min to 44.8 +/- 14.8 min for SD. The earlier T-max for AE from SD indicated the higher extent of absorption for SD due to their improved dissolution rate in rat intestine. This SD approach can therefore be used to enhanced dissolution and bioavailability for poorly water-soluble drugs. Drug Dev Res 70:363-369, 2009. (C) 2009 Wiley-Liss, Inc.