Study On Formulation Of Transdermal PSA Patch Of Chinese Medical Extract

The rubber plaster is one of the most important traditional dermal therapeutic systems,which has good adhesion property and high drug content. But the rubber plaster can induceskin anaphylaxis. The cataplasm of Chinese traditional medicine is a successful sample whichcombines foreign advanced technology with Chinese traditional medicine. The matrix iscomposed of water-soluble macromolecule material which is comfortable for the skin.However, the cataplasm is easy to brush off and has other problems of adhesive propertywhich limit its application and therapeutical effect. Acrylic pressure-sensitive adhesives(PSAs) are widely applied to transdermal drug delivery system of the chemical medicine. Ithas steady character, good skin-contact adhesion property and mild dermal anaphylaxis. PSApatch is studied in this paper.Duro-Tak polyacrylate pressure sensitive adhesive are used as matrix for PSA patch ofChinese medical extract. The appearance and adhesiveness of the patch are investigated bystudying the influence factors(type of PSAs, polymer additives, content of Chinese medicalextract, solvents in mixtrue). The influence of preparation technology and time of storage tothe in-vitro release is studied. The content of effective components in Chinese medical extrctis measured by proper HPLC method, which is studied by precision, reproducibility andaverage recovery. Moreover, optimal formulation is achieved by orthogonal and single factorexperiment. Optimal patch is single layer matrices type, its 180°peel is between 0.1 kN/m and0.6kN/m and shear is more than 9h. The in-vitro release of paeoniflorin in each patch is morethan 35％and tanshinoneⅡA is about 25％, which are more than rubber plaster. The contentof residual organic solvents is measured by proper GC method. Residual solvents in optimalpatch is lower than 5×10~3(w/w) by GC, is up to the standard of CHP 2005.In this paper, problems such as irritation,small dose and poor adhesiveness have beensolved. The technology applying Chinese medical extrct to Acrylic PSAs is feasible. Patchwith 30％(w/w) extract has been achived. It can be a promising substitute for rubble plaster.