Dissolution enhancement of curcumin by solid dispersion with polyethylene glycol 6000 and hydroxypropyl methylcellulose

Curcumin, a polyphenolic compound derived from Curcuma longa, possesses diverse pharmacologic effects such as anti-inflammatory, antioxidant, antiproliferative and antiangiogenic activities. However, curcumin has poor bioavailability and low dissolution rate due to poor absorption, rapid metabolism, and rapid systemic elimination. The aim of the study was to improve the solubility and dissolution rate of curcumin by solid dispersions. Polyethylene glycol (PEG 6000) and swellable polymers such as hydroxylpropyl methylcelluloses (HPMCs) and polyethylene oxide (PEO), were applied to improve dissolution and oral absorption of curcumin. The solid dispersions (SDs) in different ratios were prepared by hot melting method. The dissolution rate of SDs was tested in simulated gastric fluid (buffer pH 1.2) and simulated intestinal fluid (buffer pH 6.8). Samples were collected at 10, 20, 30, 60, 90, 120 minutes and replaced with an equivalent amount of fresh medium to maintain a constant dissolution volume. High-performance liquid chromatography (HPLC) method was used to determine concentration of curcumin after dissolution test. The dissolution rate of curcumin was enhanced by the incorporation into hydrophilic carrier (e.g. PEG 6000, HPMC 4000, HPMC 6, and PEO). The best percentage of drug release was observed with curcumin: PEG 6000: HPMC 4000 in ratio 1:8:4. Through the selection of polymers with optimal ratio, the SDs could increase the dissolution rate of curcumin.