| The method of high performance liquid chromatography (HPLC) was set up to determine the content of docetaxel (DCT). The solubility of DCT in different medium and the apparent oil/water partition coefficients of DCT were determined. And the stability of DCT was studied in different conditions such as strong acid, basic and high temperature. The results showed DCT has a very poor solubility both in water and oil, and was unstable in conditions above-mentioned.In the study, soybean phospholipid was used to prepare phospholipids complex by the solvent-evaporated method, then to prepare submicron emulsion. Using the stability parameter and the appearance as the index, by single factor investigation, the process was optimized as: solvent: aether, reaction time 0.5 h, drug concentration: 10 mg-mL-1, the molar ratio of DCT and phospholipid:1:2. DSC and IR were used to characterize the complex, which can prove the new DCT phospholipid complex had formed. And the solubility in soybean oil, MCT and the apparent oil/water partition coefficient were 8104.6 ug-mL-1,13909.09 ug-mL"1 and 1116.70, respectively.The method of high pressure homogenization was applied to prepare DCT phospholipid complex submicron emulsion. Single factor investigation were used to select the formulation and preparation art. The effect of the components in the formulation such as the amount of oil and oleic acid, the amount and composition of emulsifying agents, pH of the emulsion and the sterilization method were investigated. The effect of variable factors in preparing art such as emulsifying temperature and time, the pressure and cycle times of the homogenizing process were also investigated. Then the basic formulation of DCT phospholi- pid complex submicron emulsion was optimized by orthogonal design test, using the stability parameter as the index. The best formulation contained MCT 15%, soybean phospholipids 2.4%, Tween-80 0.6%, DCT 0.4%, oleic acid 0.4%, VE 0.01%, glycerol 2.25%. The best processing parameters were the first emulsifying temperature 70℃, emulsifying for 10 min, the pressure of homogenization at 30 Mpa, cycling for 4 times. The DCT phospholipid complex submicron emulsion was emulsus and opalescence, with the particle size about 150 nm, pH 5.5-6.5, content of DCT 98.3%, entrapment efficiency(EE) 99.4%. The submicron emulsion displayed good compatibility with glucose injection (5%) and sodium chloride injection (0.9%), which was safe to use within 6 h. Accelerated test at (25±2)℃indicated that the appearance has no change, but the pH and the content of DCT decreased. And long-term test at (4±2)℃showed that there was no significant change of the appearance, the content of the drug and other parameters. Therefore, the submicron emulsion was stable in low temperature.The DCT phospholipid complex submicron emulsion caused neither hemolysis nor blood clotting. The Pharmacokinetics of the submicron emulsion in rats was studied. A reliable analysis method by HPLC was established to determine the concentration of DCT in rat plasma. After iv administration at a single dosage of 10.0 mg-Kg-1 in rats, the concentration- time curve fitted one compartment model treated by 3p87. Then the data of experiment were treated by Statistic Quadrature. The results manifested that the DCT phospholipid complex submicron emulsion had a higher AUC, AUMC, MRT compared with the DCT injection.
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