To improve its poor aqueous solubility and stability, the potential chemotherapeutic drug quercetin was encapsulated in soluplus polymeric micelles by a modified film dispersion method. With the encapsulation efficiency over 90%, the quercetin-loaded polymeric micelles (Qu-PMs) with drug loading of 6.7% had a narrow size distribution around mean size of 79.00 ± 2.24 nm, suggesting the complete dispersibility of quercetin in water. X-ray diffraction (XRD) patterns illustrated that quercetin was in amorphous or molecular form within PMs. Fourier transform infrared spectroscopy (FTIR) indicated that quercetin formed intermolecular hydrogen bonding with carriers. An in vitro dialysis test showed the Qu-PMs possessed significant sustained-release property, and the formulation was stable for at least 6 months under accelerated conditions. The pharmacokinetic study in beagle dogs showed that absorption of quercetin after oral administration of Qu-PMs was improved significantly, with a half-life 2.19-fold longer and a relative oral bioavailability of 286% as compared to free quercetin. Therefore, these novel soluplus polymeric micelles can be applied to encapsulate various poorly water-soluble drugs towards a development of more applicable therapeutic formulations.

The objective of this study was to prepare curcumin-loaded mixed Soluplus/TPGS micelles (Cur-TPGS-PMs) for oral administration. The Cur-TPGS-PMs showed a mean size of 65.54 ± 2.57 nm, drug encapsulation efficiency over 85%, and drug loading of 8.17%. The Cur-TPGS-PMs were found to be stable in various pH media (pH 1.2 for 2 h, pH 6.8 for 2 h, and pH 7.4 for 6 h). The X-ray diffraction (XRD) patterns illustrated that curcumin was in the amorphous or molecular state within PMs. The In vitro release test indicated that Cur-TPGS-PMs possessed a significant sustained-release property. The cell viability in MCF-7 cells was found to be relatively lower in Cur-TPGS-PM-treated cells as compared to free Cur-treated cells. CLSM imaging revealed that mixed micelles were efficiently absorbed into the cytoplasm region of MCF-7 cells. Therefore, Cur-TPGS-PMs could have the significant value for the chronic breast cancer therapy.