Studies On Rubescens Total Diterpenoids For Injection

The latest researches indicate that Rabdosia rubesecns (Hemls.) Hara possesses distinctive effect and low toxicity in anti-cancer therapy. Rubescens total diterpenoids(RTD) are main compounds in Rabdosia rubesecns (Hemls.) Hara and they have good anti-cancer activity also. The main objectives of this research were to raise the content of RTD in the utility regional by modern isolating and purifying technique, Establish a accurate and practical method for the quality control of RTD and preparation, improve the solubility of RTD in water by introducing hydroxpropy-β-cyclodextrin ( HP-β-CD) into the system. And all above are aim to elevate the anti-cancer effect and clinical therapeutic effect of RTD.A sensitive and specific RP-HPLC method was set up to determin oridonin(ORI) taked as indices in RTD. And UV method was used as quantitative analysis method to control the content of RTD.Cold-soak with alcohol method was used to extract the utility regional, pigments and ceroleins were removed by leading in water. And resin was introduced to refine the RTD. As the results described, the purity of the RTD was more than 70% and the yield is 1.2%. Validation results show that the progress of extracting and purifying is simple and stable.Solubility and stability of RTD were investigated by determining the content of ORI. The results show that ORI is sparingly soluble in PEG400, propylene glycol and ethanol; slightly soluble in glycerin; very slightly soluble in water. The solubility of ORI is significantly improved at pH 9. After megatemperature, homo-humidity and illumination tests, it was found that ORI is stable at solid state. The results demonstrated that ORI solutions were most stable at pH 6 and very unstable under acidic or alkaline conditions.Phase-solubility method was preformed to investigate the complexation of RTD with HP-β-CD in aqueous solution. The solubility of ORI increased linearly with increasing HP-β-CD concentration in various aqueous solutions, showing typical A_L-type phase solubility profile. The apparent stability constant at different pH-value, temperature and ion strength was calculated, respectively. Thermodynamic parameters during the inclusion process are as follows:ΔH=17.31 kJ.mol^-1,ΔS=39.57 J·mol^-1,ΔG＜0. The results indicated that ORI solubility in water could be improved by introducing HP-β-CD into the system. By the stoichiometric analysis, the molecular ratio of the ORI-HP-β-CD complex is 1:1. The complex process is endothermic and spontaneous.RTD-HP-β-CD injections were prepared And some tests, hemolysis and initial stability of the injections were examined. Results show that RTD-HP-β-CD injections have no hemolysis,and preparation is stable at ambient temperature and at 40℃after 3 months.Lastly, the method of RP-HPLC was established for determining ORI in rabbit serum. Gliclazide was used as internal standard. Tests have been carried out to study the pharmacokinetics of ORI in rabbits with two administration ways: intravenous injection and muscular injection. The serum concentration-time data were analyzed by 3p87 program and non-compartmental model. It was found that the serum concentration-time curves of the two administration were fitted into a two-compartment model and the absolute bioavailability of ORI at i.m. admisinstration was 54.55%.