Preparation and stability evaluation of artemether-loaded mixed micelles composed of the sodium glycocholate and soybean lecithin

In this study, artemether (ARM)-loaded mixed micelles (MM) composed of the sodium glycocholate (SGC) and soybean lecithin (SL) were prepared by film dispersion method. The effects of hydration medium, SL mass ratio and total concentration of excipients on the solubilization of ARM were investigated and the stability of MM was evaluated. Results showed that the particle size distribution of SGC-SL-MM prepared by phosphate buffer solution (PBS, pH 7.4, 0.05 mol·L^-1) was uniform, with an average size of 3.58 ±0.14 nm and the polydispersity index (PDI) value was 0.16 ±0.04. The solubility of ARM increased significantly from 0.64 ±0.04 mg·mL^-1 to 13.7 ±0.13 mg·mL^-1 along with the concentration of total excipient increasing from 1.0% to 30.0% (w/w). The calculated results of Arrhenius parameter and storage stability showed that the degradation rate constant of ARM in MM was smaller than that in acetonitrile-PBS (pH 7.4) at either 37 ℃ or 60 ℃. The experimental ARM-MM was clear after storing for two months at 25 ℃ and the degradation of ARM was less than 7.0%. In conclusion, the SGC-SL-MM can not only improve the solubility of ARM in aqueous solution, but also improve its chemical stability in aqueous solution at low temperature.