The Investigation Of Methotrexate Microemulsion

Objective:To prepare methotrexate microemulsion (MTX-ME), and evaluate the quality ofmethotrexate microemulsion, investigate the ability of percutaneous penetration of methotrexate microemulsion in vitro and the effects of methotrexate microemulsion on pathological models of psoriasis.Methods:(1) The formulation was investigated by pseudoternary phase diagram obtained by titration method and the maximum loading of the oil in different systems. methotrexate was determined by RP-HPLC method and physical appearance,particle size with distribution,Zata potential, contents of methotrexate and value pH were used as. indexes to evaluate the stability of methotrexate microemulsion. (2) TP-5 diffusion cell was used in vitro permeation study.The concentration of methotrexate in the receptor solution by HPLC, and methotrexate microemulsion whose concentrations were 0.2%,0.1% was coparad with Methotrexate control solution whose concentration was 0.2%. (3)①In vitro,the vaginals of mice which were in estrogen phase were swabbed with methotrexate microemulsion(0.1% and 0.2%) and of tretinoin ointment(0.1%),once a day,seven days successively.The indexes of mitosis of vaginal epidermal cells were investigated.②In vitro, the methotrexate microemulsion(0.1% and 0.2%) and of tretinoin ointment(0.1%) were spread on tails of mice, once a day, seven days successively. To observe the cornification improvement of tails epidermis in mice.Results:The optimized formulation was composed of Cremophor RH-40/soybean phosph-olipid mixture-dehydrated alcohol-ethyl oleate(3:1.5:1.5:3). For methotrexate microe-mulsion,the physical appearance was transparent and uniform.The average diameter was 25.1 nm with a polydispersity index of 0.273,the Zata potential was-1.723mV. The MTX contents of each batch were 1.99±0.01、2.02±0.03、2.00±0.02 mg·mL-1. In vitro, the Qn of methotrexate microemulsion whose concentration was 0.2% at 9 hours was 2.04 and 2.34 higher separately than that of concentration of 0.1% of microemulsion and concentration of 0.2% of control solution(P<0.05).In pharmacological study, low dose methotrexate microemulsion group and vitamine A acid cream group can inhibit the mitosis of vaginal epidermal cells of mice in estrogen phase,and imp-rove the comification of tails epidermis in mice comparing with the blank control(mitotic index; number of scale with granular layer P<0.05) individually; and the difference of the two group was statistic ally significant. High dose methotrexate microemulsion group and vitamine A acid crea-m group can also inhibit the mitosis of vaginal epidermal cells of mice in estrogen phase, and i-mprove the comification of tails epidermis in mice (mitotic index; number of scale with granular layer P<0.01). Comparing with the positive control, the difference of high dose methotrexate mic-roemulsion group group and low dose methotrexate microemulsion group was statistic ally signi-ficant.highly(mitotic index; number of scale with granular layer P<0.05).Conclusion:The physicochemical properties of methotrexate microemulsion were relatively stable, the technology of preparing methotrexate microemulsion was easy and the quality of methotrexate microemulsion was easy to control. In vitro, the transdemal delivery ability of methotrexate is significantly increased with 0.2% of microemulsion and concentration compared with 0.1% of microemulsion and concentration of 0.2% of control solution. During the evaluation of effects of this drug, compared with tretinoin ointment which was used for curing psoriasis commonly, methotrexate microemulsion can improve the recovery of pathological models of psoriasis more obviously.