Studies On Preparation And Qualities Of Temozolomide Intravenous Emulsion

Currently, the incidence of malignant brain tumors is not optimistic. According to the statistics, malignant brain tumors account about60%of primary brain tumor and the global incidence of malignant brain tumors is6to8/100000by now. The standard treatment is surgical resection of the tumor and postoperative radiotherapy. The high incidence of malignant brain tumors promote the development of temozolomide which has over30years history. Up to2005, temozolomide have already come to the global market in dozens of countries and regions. Now it is evaluated to be "gold standard" by United States and Europe for the treatment of malignant brain tumors. The international medical community has taken the temozolomide as first-line drug in the treatment of malignant brain tumors. Currently, the common oral formulations of temozolomide have large drawbacks. The main side effects are nausea, vomiting, fatigue, constipation and mild bone marrow suppression. Among them, incidence rates of severe nausea and vomiting are10%and6%respectively. Because nausea and vomiting can lead to insufficiency drug absorption, patients usually take antiemetic medication before taking temozolomide which brought great suffering and economic burden to patients. Besides, the patient is often not applicable to solid drugs after surgery. What is more, coupled with the traditional clinical drug habit, temozolomide intravenous injection will be more suitable for patients and it will not only improve patient medication compliance, but also meet the clinicians drug habit.As an intravenous parenteral nutrition preparation, there are more and more drug-loaded intravenous emulsions are being studied. Lipid soluble drugs or drugs insoluble in oil and water are suitable to be prepared into intravenous emulsions, which has many advantages, such as small size, high energy, less vein irritation, peripheral intravenous administration, increasing drug solubility, reducing adverse reactions, low cost, could be autoclaved and high long-term stability, IN addition, it also has targeted and sustained release quality. The preparation method is simple, and it is conducive to transforming large-scale production. Besides, it has the dual role of nutrition and treatment, and has high R&D value.Considering temozolomide is unstable in water, making it into intravenous emulsion can improve its stability. Meanwhile it has certain nutritional role for the high-risk cancer patients; besides, the targeting distribution in vivo can enhance its efficacy while reducing toxic effects. Therefore, the thesis takes temozolomide as model drug to prepare temozolomide intravenous emulsion, and research its qualities. The studies included four parts:preformulation studies of temozolomide intravenous emulsion, studies on preparation and physicochemical properties of temozolomide intravenous emulsion, in vitro studies on release behavior and stabilities of temozolomide intravenous emulsion and preliminary safety evaluation of temozolomide intravenous emulsion.1. Preformulation studies of temozolomide intravenous emulsionUltraviolet spectrophotometry was established for content determination of temozolomide in temozolomide intravenous emulsion, and HPLC was established for related substances determination of temozolomide intravenous emulsion. Results showed that the two methods were both simple, sensitive with good reproducibility. Besides, they were stable for solution determination and the linearity was good. Those could meet with? the verification requirements on analytical methods. The equilibrium solubility and oil/water partition coefficient of temozolomide in different solution were measured. Results showed that temozolomide equilibrium solubility decreased with pH increasing, while the oil/water partition coefficient increased with pH increasing. Those data provided theoretical basis for absorption and also provided references to other relevant studies.2. Studies on preparation and physicochemical properties of temozolomide intravenous emulsionTemozolomide intravenous emulsion was prepared by using high pressure homogenization method and SolEmuls technology. The optimized formulation and processes were obtained by preliminary screening and single factor investigation of formulation and procedure. The aqueous phase of optimal formulation were mixed emulsifiers with SPC1.6g and F680.8g, glycerin2.2g, temozolomide100Omg, and80ml water for injection. The oil phase of optimal prescription were soybean oil10g, medium chain oil10g and oleic acid1g. The optimal procedure was as follows:oil phase was added to aqueous phase which was sheared at10000rpm, then the initial emulsion was sheared for5min after adding the oil phase. Temozolomide intravenous emulsion was obtained after high pressure homogenization(1000bar,15cycles) and filtered through0.22μm. Temozolomide intravenous emulsion had good reproducibility. Results for physicochemical properties were:pH5.38; mean diameter171.1nm; Zeta potential-44.89mV; drug loading0.98mg/ml and related substances0.14%. Results showed that temozolomide intravenous emulsion with good properties was prepared successfully.3. In vitro studies on and stabilities of temozolomide intravenous emulsionPH6.8PBS was used as release medium to research the in vitro release behavior of temozolomide intraenous emulsion. Temozolomide was released quickly from its aqueous solution, while temozolomide intravenous emulsion could release the drug slowly.The3h cumulative release percentage were98.66%and98.66%respectively, almost released completely. The release of temozolomide aqueous solution was fitted with first-order kinetic model, while Ritger-Peppas or Weibull equation best fitted for temozolomide intravenous emulsion. Results showed that drug could be sustained released from temozolomide intravenous emulsion. The stability of temozolomide intravenous emulsion was researched with using appearance, particle size, pH, drug content and related substances as evaluation index. Results showed that temozolomide intravenous emulsion has good centrifugal stability and should not be freezed-thawed repeatedly to ensure the quality of the preparation. Temozolomide intravenous emulsion was sensitive to high temperature, low temperature and strong light irradiation, and should be stored in the shade. The appearance, particle size, pH, drug content and related substances could still meet with the requirements after placed in the shade for6months under the condition of25℃±2℃of accelerated test and6℃±2℃of long-term test, showing good stability.4. Preliminary safety evaluation of temozolomide intravenous emulsionThe irritation of administration place was evaluated by injecting temozolomide intravenous emulsion into the ear margin vein of rabbits and the hemolysis was evaluated by in vitro tube test. Local irritation test results show that temozolomide intravenous emulsion have no excitant; besides, hemolysis test results show temozolomide intravenous emulsion does not induce hemolytic reaction. Therefore, temozolomide intravenous emulsion has good security, suitable for intravenous injection.Conclusion:Temozolomide intravenous emulsion was prepared successfully in this subject with using simple method, and its good quality and stable physical-chemical properties are suitable for injection. The intravenous emulsion could release the drug slowly and had good stability in vitro, having no vascular stimulation and hemolytic reaction with better security. Temozolomide intravenous emulsion is a nutrition preparation with therapeutic function with high value for research and application.