ABSTRACT
OBJECTIVE: To prepare oridonin-loaded cubosomes, and encapsulate oridonin(ORI) for the purpose of enhancing the solubility and prolonging the action time. METHODS: Phytantriol (PYT) was firstly used to cooperate with Poloxamer 407-propylene glycol-water system to improve the solubility of ORI for developing ORI-loaded cubosomes. Polarizing microscope, small angel X-ray scattering (SAXS) and cryogenic transmission electron microscopy(cryo-TEM) were used to study the characters of cubosomes. RESULTS: Under homogenization conditions of 1 200 bar for 9 cycles, the obtained PYT-based cubosomes had narrow particle size distribution with a mean particle size of (225.9 ± 5.6) nm. The internal structures of cubosomes were revealed by small-angle X-ray scattering as a bicontinuous cubic liquid crystalline phase with Pn3m geometry. The encapsulation efficiency and drug loading determined by ultrafiltration centrifugation were (86.6 ± 1.5)% and (3.69 ± 0.06) mg•g-1, the solubility of ORI had been increased by 5.20 times. CONCLUSION: The optimized formulas of cubosomes show obvious 24 h-sustained release, and the in vitro release profiles fitt the Higuchi release model well, implying diffusion-control as main release mechanism.
ABSTRACT
OBJECTIVE: To investigate the in vitro drug release characteristics of in situ phytantriol liquid crystalline for hepatical arterial embolization. METHODS: The release study was conducted using dialysis membrane tubing. The influences of initial compositions of in situ phytantriol liquid crystalline, drug loading, iodinated oil and rotation speed on dissolution behaviour were investigated respectively using docetaxel as the model drug. Moreover, the elasticity of phytantriol liquid crystalline was investigated by rheo-logical measurement. RESULTS: The in vitro release profile could be described by Higuchi model. No significant difference in drug release behaviour was observed under different rotation speed. Nevertheless, the drug release rate decreased with increasing drug loading and phytantriol content. Furthermore, iodinated oil was found to relive the burst effect to a certain extent. And the maximal pressure load of phytantriol liquid crystalline was (3070 ± 2.135) Pa. CONCLUSION: The in situ phytantriol liquid crystalline can sustainedly release drug for up to 30 d and has good elasticity, which suggests that the in situ phytantriol liquid crystalline can be hopefully applied in clinic for combination of embolization and chemotherapy. Copyright 2012 by the Chinese Pharmaceutical Association.