Study On The NCTD Lipomicrosphere For Injection

Lipid microsphere (LM) is recently used as intravenous (i.v.) carriers for drugs, especially for anti-tumor or anti-inflammatory drugs, which have enough solubility in oil. Drugs are usually incorporated into the oil phase or into the interface of oil phase in LM, so it was presumed to avoid or reduce local or blood vessel irritation.Norcantharidin (NCTD) is one of new chemotherapy agent that was firstly synthesis in china. NCTD has proved to show excellent activity against cancer, especially against primary hepatic carcinoma. To enhance solubility of NCTD, the clinical used NCTD sodium salt is adjusted to high pH (about 9.0), which is an important causation of its irritativeness in situ for intravenous infection. At the same time, NCTD itself was reported to cause irritation. In present study, a technique and formulation are developed to prepared a kind of NCTD corporated LM to decent irritation and elevate compliance in clinical. The oil phase or the surfactant layer were assignment as the main drug loading position during the preparation investigation. Different formulation and craft were sieved to raise the corporation ratio over 80%, and then the detection of pharmacokinetics character in rats and animal test of safety of NCTD LM was undertaken.An HPLC—anion-exchange method was established for determination of NCTD. The method is simple, rapid, acute, sensitive, reproducible and suitable for the quality control of NCTD LM. The solubility of NCTD in pH 1.0,pH 5.6. pH 8.0. pH 10.0 were 3.15,5.59,8.90,29.33,6.72 mg ? mL^-1 respectively. The coefficient of oil-water distribution rises with decent of pH.For the poor solubility of NCTD in both water and oil, so the corporation ratio was the main evaluation parameter with the stability of formulation was ensured beforehand. Different injectable excipients and preparation condition were compared to improve the stability and incorporation capacity of the LM system. The homogenization temperature, pressure, times and the way of addition of NCTD was optimized. The effect of pH and composition of oil phase as well as surfactant on the character of LM was detected.The result showed that the amount and composition hold the most distinct influence on the stability of NCTD LM. Little oil droplet was visible after sterilization in the formula that lecithin was used as sole surfactant. When the amount of lecithin dropped to 0.6%, the formula was unstable during sterilization either. The formula showed satisfactory stability character when the total amount of surfactant was 1.2% with leicithin-F68 (0.6:0.6). The main factor affecting drug distribution were proportion of MCT in oil phase and pH of LM. The corporation ratio of NCTD in oil and surfactant layer increased with addition of MCT. But the formula is not stable when only MCT was used. Low pH can also enlarge the corporation ratio. When the pH was adjust to 7.0 and MCT—LCT (7.5: 2.5), the distribution of NCTD in oil phase and surfactant layer was above 80%.The oil phase was composed of injectable soybean oil -MCT (2.5: 7.5), the total amount of surfactant was 1.2% with leithin-F68 (1: 1), and the oleate sodium was 0.03%. PH was adjusted to 6.5 before homogenization, and the homogenization condition was 800 bar, 6～10 times, filling in with nitrogen. The samples was autoclaving under 121℃, 15 min. The mean particle size was 195.2 nm, and the incorporation ratio was 84.6%.Dilution test revealed that the sodium chloride injection (0.9%) diluted samples turned to unstable with particle size,ζ-potential and drug corporation ratio changing markedly. The samples diluted with glucose injection (5.4%) show good stability. When the dilution multiple was 5, there was about 80% after 2 h. So the glucose injection (5.4%) was suggested to used as dilution medium. The stability test showed that NCTD LM showed no significant change after 6 months under 25±℃and 6±2℃.Established a HPLC-MS method for the determination of norcantharidin in rat plasma. The result plasma concentration showed that the NCTD LM and the reference NCTD solution were of two compartments. The relative AUC value ofNCTD LM to solution was 100.34% and the two c-t curves were alike with pharmacokinetics parameters showed no distinct differenceThe security test showed that the LD₅₀ of NCTD LM was 18.6mg/kg, while that of soluteion was 16.1 mg/kg, suggested that the reduction of side effect. The NCTD LM caused no hemolysis and no stimulation on vein. The rat paw lick test showed that there was distinct difference between times of rats licked their paw with same amount NCTD LM and solution been injected. The test suggested the possibility that the NCTD LM may be only 50% as painful as solution.