Preparation And Preliminary Quality Evaluation Of Meifuling Microemulsion

OBJECTIVETo construct the system of Meifuling microemulsion and establish the quality evaluation system to make basis for the development of Meifuling transdermal drug delivery system and provide a reference for the microemulsion's preparation of the similar chinese herbal compound.METHODS1. Extract the effective parts of the Meifuling's crude drugExtraction of Periplanta americana:dried the crude drug at 60℃for 3h, then soaked the medical materials 12h with 10 times'95% ethanol three times, the filtered liquor was concentrated to clarinex syrup at 60℃, then the materials of clarinex syrup was to be standing and stratificated with 5 times'physiological saline at 60℃, filtered the lower aqueous solution and got the clarified solution, then concentrated the above solution to get the medicinal extract.Extraction of Centella asiatica L.Urban.:dried the crude drug at 60℃for 3h, then extracted the medical materials 4.5h with 16 times'55% ethanol with refluxing extraction.Extraction of Glycyrrhiza uralensis Fisch.:dried the crude drug at 60℃for 3h, then extracted the glycyrrhizic acid with 14 times'water of which the content of ammonia gas is 1.5% at room temperature, and the value of PH of acid precipitation is 1.5.Extraction of Lthospermum erythrorhizon Sieb.et Zucc:dried the crude drug at 60℃for 3h, then extracted the medical materials 3h with 14 times' 95% ethanol with refluxing extraction.2. Prescription screening of Meifuling microemulsionConsidering the solubilization of L-shikonin in the medium-chain fatty acid ester (C8-C10),isopropyl myristate,ethyl oleate and oleic acid, and the area of the microemulsion phase region to screen the oil phase; With Tween 80 and Span 80 as surfactant and 1,2-propanediol,ethanol,polyethylene glycol 400 and glycerol as the cosurfactant to draw the pseudo-ternary phase diagram and screen the prescription system with larger microemulsion region; By centrifugation and stability,the curve of electrical conductivity and water content,the relationship between the drug dose and the viscosity screen the optimizated microemulsion prescription system.3. Preparation of Meifuling microemulsionWeigh a certain amount of extract of Centella asiatica L. Urban. and glycyrrhizic acid extracts to dissolve in the medicinal extract of Periplanta americana, after 30 minutes'ultrasonic oscillation and filtration to get the water phase, and weigh a certain amount of the extract of Lthospermum erythrorhizon Sieb.et Zucc. to dissolve in isopropyl myristate, after 30 minutes' ultrasonic oscillation and filtration to get the oil phase, then mix and uniform the oil phase,surfactant and cosurfactant together, with the phase inversion method to prepare Meifuling microemulsion.4. Quality evaluation of Meifuling microemulsionEstablish the HPLC method for the determination of the content of asiaticoside and L-shikonin in Meifuling microemulsion; With the naked eye and transmission electron microscopy observe the appearance and shape of Meifuling microemulsion; By centrifugation,dilution and dyeing identify the type of the Meifuling microemulsion; With the nano-particle size and ZETA potential analyzer determine the and particle size distribution; To influence factor tests,accelerated tests and long-term experiments investigate the stability of Meifuling microemulsion.RESULTS1. Determination of the indicator's content in the extracts of Meifuling microemulsionThe parts of Periplanta americana extracted by water contain 20.65% of total amino acids with glycine calculated; The extract of Lthospermum erythrorhizon Sieb.et Zucc.contains 21.64% of L-shikonin; The extract of Centella asiatica L.Urban. contains 7.55% of asiaticoside.2. Prescription screening of Meifuling microemulsionPseudo-ternary phase diagram screened the system of Tween 80-glycerol-isopropyl myristate-water, the final results of optimized prescription is that in the system the content of each component is:Tween 80 33.4%, Glycerol 16.7%, isopropyl myristate 6.5%, water 43.4%, calculated by volume.3.Quality evaluation of Meifuling microemulsion The concentration of asiaticoside is 0.608 mg/ml, and the concentration of L-shikonin is 0.287μg/ml; The microemulsion is the type of oil-in-water with clarification, red-brown and special flavor. The average diameter is 47.75 nm with polydispersity index of 0.637; The results of factors,long-term experiment and accelerated tests show that the content of asiaticoside and L-shikonin is stable.CONCLUSIONSThe oil phase can dissolves fat-soluble extracts of Lthospermum erythrorhizon Sieb.et Zucc. and at the same time the water phase dissolves the extract of Centella asiatica L.Urban.and Glycyrrhiza uralensis Fisch.in Meifuling microemulsion; Meifuling microemulsion can be formed and keep stable, so construct the system of Meifuling microemulsion.Establish the quality evaluation system of Meifuling microemulsion and provides a reference for the microemulsion's preparation of the similar chinese herbal compound.