Preparation and evaluation of curcumin-loaded self-assembled micelles

Abstract

Objective: Curcumin being used to treat various chronic diseases while its poor bioavailability issue limited its wide clinical application as a therapeutic agent. The aim of this work was to prepare curcumin-loaded self-assembled micelles using soluplus and solutol^®HS15 (SSCMs) to enhance curcumin's solubility and thus oral bioavailability.

Methods: Optimum formulation was investigated and the optimized ratio of drugs and excipients was obtained and the SSCMs were prepared via ethanol solvent evaporation method. The optimal SSCMs were characterized by transmission electron microscopy, drug content analysis including loading efficiency (LE%) and entrapment efficiency (EE%), and the cumulative amount of curcumin released from the micelles were all calculated using HPLC method. The in vitro cytotoxicity and the permeability of SSCMs were measured by Caco-2 cell monolayers and the oral bioavailability was evaluated by SD rats.

Key findings: The solubility of curcumin in self-assembled micelles was dramatically increased by 4200 times as compared to free curcumin. Caco-2 cells transport experiment exhibited that while soluplus and solutol^®HS15 were self-assembled into micelles, it could not only promote the permeability of curcumin across membrane for better absorption, but also could restrain the curcumin pumped outside due to the role of P-gp efflux mechanism of soluplus and solutol^®HS15. Furthermore, the prepared SSCMs formulation was almost nontoxic and had safety performance on Caco-2 cells model. Moreover, curcumin's oral bioavailability of SSCMs formulation in SD rats had doubled than that of free curcumin.

Conclusions: The prepared SSCMs were characterized by PS, PDI, LE%, EE% data analysis. After the soluplus and solutol^®HS15 were self assembled into micelles, both the solubility and membrane permeability of curcumin were evaluated to have been enhanced, as well as the effect of efflux pump of curcumin was inhibited, hence to promote oral absorption and generate an increased bioavailability.

Keywords: Curcumin; bioavailability; micelles; soluplus; solutol®HS15.