The physicochemical characteristics of freeze-dried scutellarin-cyclodextrin tetracomponent complexes.

In an effort to improve the solubility of the insoluble drug scutellarin, a novel complexation of scutellarin with beta-cyclodextrin (beta-CD) was studied. Tetracomponent freeze-dried complex was prepared with scutellarin, beta-CD, Hydroxypropyl Methylcellulose (HPMC), and triethanolamine. To confirm complex formation, complex was characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction, and differential scanning calorimetry (DSC). Phase-solubility analysis suggested the soluble complexes having 1:1 stoichiometry. The beta-CD solubilization of scutellarin could be improved significantly by combining water-soluble polymer and pH adjuster. Comparing the binary, ternary solid systems with tetrary systems, tetracomponent freeze-dried complex showed the best effect of solubilization. A maximal solubility of scutellarin (23.65 mg/ml) was achieved with tetracomponent freeze-dried complex, up to 148-fold increase over scutellarin solubility in water, and the solubility of scutellarin is 15.35 microg/ml (up to 6-fold) in simulated gastric fluid.