Investigation Of 2-methoxyestradiol Intravenous Emulsions

2-Methoxyestradiol(2-ME),which is studied at clinical phaseⅠ,Ⅱabroad,is a natural estrogen metabolite with the characteristics anti-tumors activity.2-ME has the manners of time-concentration-dependent,low solubility(approximately 0.2206μg·ml^-1);lack of correlation between oral absorption and dose;and it can rapidly produce inactive metabolites due to easy hydroxylation,dehydrogenation in vivo.The above causes resulted in shorter half-life and low oral bioavailability.The emulsion has the roles of delayed-release and increase bioavailability.The purpose of the study is to prepare o/w intravenous emulsion of 2-ME and investigate the safety,efficacy, delayed-release and targeted effect to tumors cells,and provide the research base for new formulations of 2-ME.Formulation design and preparation technique of 2-ME intravenous emulsion was studied,the solubility of 2-ME in soybean oil and water were 1.05 mg·ml^-1,0.2206μg·ml^-1 at 25℃respestively,the lipid water partition coefficient(logP) was 4.41 at 25℃,so 2-ME could be dissolved in soybean oil to prepare emulsion.The effects of the percentage of soya bean oil,the percentage of emulsifier,the ratio of between phospholipids and poloxamer,the ratio of between drug and phospholipid and the influennces of emulsification temperatures,emulsification time,homogeneous stress and homogeneous times on the emulsion quality were studied,Then based on the results of single factor analysis,the formulation and the preparation techniques were optimized by orthogonal design.The pharmaceutical properties of 2-ME intravenous emulsion were as followings: particle size 246.2±5.6 nm,Zeta potential -32.47±1.51 mv,pH value 7.32±0.12, viscosity 1.423±0.005 mpa.S.The physicochemical properties of 2-ME intravenous emulsion were coincident with the Chinese Pharmacopoeia.The centrifugal test, impact factor test,frozen-heating cycle test,accelerated test and long-term test were conducted to investigate the stability of emulsion,the results showed that the particle size didn't increase significantly,indicating that the emulsion had good stability in frozen conditions.The accumulated release amount of 2-ME control solution was up to 50%in 30 min,up to 90%in 2 h,the accumulated release of 2-ME emulsion was about 50%in 6 h,about 90%in 30 h.Showing that 2-ME emulsion had slow-release effect compared to 2-ME control solution.The preliminary safety of 2-ME emulsion was evaluate by acute toxicity test, vascular irritation test,haematolysis and hypersensitiveness test.The results showed that the emulsion had no obvious toxicity,irritation,haemocytolysis and hypersensitiveness.The effects of the 2-ME control solution and 2-ME emulsion on the MCF-7 cell proliferation inhibition were investigated by use of MTT method, indicating that inhibition effect was increased with time and dose increment, 2-ME-emulsion had slow-release effect compared to 2 -ME control solution.2-ME blood concentration of mice were determined by HPLC with fluorescence detector to explore pharmacokinetics parameters for 2-ME intravenous emulsion and 2-ME control;At the same time,the 2-ME distribution in mice were investigated for 2-ME intravenous emulsion.Showing that 2-ME emulsion has a sustained-release and tissue targeting in lung,liver,spleen compared to 2-ME control solution.