Abstract
The control of adhesion properties such as pressure sensitive adhesion and tack (initial pressure sensitive adhesion) is important in external applications of plasters or poultices, including transdermal drug delivery systems, hospital tapes, first aid tapes and others. Excessive tack and pressure sensitive adhesion may cause skin irritation and other maladies. These problems must be overcome when developing external applied preparations.In our previous paper, tacks expressed as rolling friction coefficients of polyvinyl alcohol (PVA) hydrogels were determined by the rolling cylinder method, and viscoelasticities were determined by dynamic viscoelastic methods.The correlation between tacks and viscoelasticities, such as storage modulus and loss tangent, was found to be high using the statistical method of multi-regression analysis.In the present study, the experimental results from tack and viscoelastic data of PVA hydrogels were compared with theoretical values by curve fitting.Theoretical curves were calculated by computer simulation methods according to our equations, based on a four elements mechanical model (two Maxwell elements in parallel connection), failure criteria and viscoelastic data of PVA hydrogels.Tack for external applied preparations formed as plasters and poultices could be predicted by these results. The prediction methods proposed in this paper are essential for establishing the ideal tack of plasters and poultices in the stage of pre-formulation.
