Standard Research On Percutaneous Penetration Test In Vitro For Chinese Medicine Dermal Patches

Xuetiedingchuan plaster and ChuanXiong piaster are used as model drugs, theireffective components as index, we study on preparation for transdermal test methodologyresearch in vitro. Magnolin is studied on in vitro/in vivo correlation as well. The testplasters as the object are used to make a regulation for methodology of transdermal test invitro and quality assessment method. Four patches in the literature of in vivo dermalabsorption are chosen to study on in vitro/in vivo correlation experiments, methodology ofpercutaneous penetration test is validated to be rationality and reliability.Partition coefficient of drugs between water and n-octanol(P) is used to judge the drugwhether hydrophilic or lipophilic. Generally speaking, P=1(logP=0), the drug is consideredto be lipophilic; P＜1 (logP＜0), the drug is considered to be hydrophilic contrarily. Byshaking bottle method, magnolin’s P is determined to be 1.252±0.030 and ligustrazinehydrochloride’s P is 0.536±0.021.In vitro diffusion experiments have become one of the most important kinds of studiesof transdermal forms for drug administration, not only in the development of newformulations but also for quality control of the final preparations. The contents of study onmethodology of transdermal test in vitro include skin models for in vitro penetrationstudies; the choice of receptor fluid; penetration cell design et al.Nine excised skins ofvarious species and artifical composite membranes can be used for comparisons. Thecellulose nitrate filter impregnated with IPM or hairless mouse skin can be regarded as agood model for the study of percutanous permeability of test compounds. They are muchmore reproducible, easily manufactured, manipulated and regulated. The choice of receptorfluid depends on the solubility of drug ingredients in the intended receptor fluid. By asufficient number of comparisons, a saline or pH7.4 buffered saline solution isrecommended for hydrophilic compounds. For lipophilic molecules, 10％PEG400/40％ETOH/Saline is more applicable to test substances. The permeation equipment is based onthe conventional Franz cell. In the flow-through design, the continuous flow through the receptor chamber helps to maintain sink conditions throughout the course of an experimentwith peristalsis pump, which is an important feature to be taken into account. On the otherhand, this kind of cell is more suitable for the simulation of in vivo conditions, incomparison to the classical static Franz-type cells. The temperature in the bulk of solutionis maintained by circulating thermostated water through a water jacket that surrounds thereceptor compartment. Establishing an in vitro-in vivo correlation using four model drugsthat have different lipophilicities, comparing capability between Franz diffusion cell andflow-through diffusion cell, we find that the new system which has more rational adaptionis desired to be used widely.Quality assessment method and evaluation standard on percutaneous penetration testof traditional Chinese medicine dermal patch are established, quality evaluationmethodology problem for this kind of preparation has been solved currently, then research,development, production, examination and approval for this kind of preparation willprovide the reference for for study、manufacture、supervise on those preparations in thefuture.