Adhesion testing of transdermal matrix patches with a probe tack test – In vitro and in vivo evaluation

It was the aim of the study to evaluate the suitability of the probe tack test as a method of predicting the long-term adhesion properties of transdermal patches to human skin. Twelve different types of polyacrylate pressure sensitive adhesives have been characterized using the probe tack test. For the analysis of the obtained data a novel procedure was developed that is based on two parameters: the deformation compliance κ and the critical return speed vc. In addition to the in vitro characterization, the in vivo adhesive properties were investigated in a double-blinded and randomized wear study by eight volunteers for a period of 7 days of wear. The adherent area and the size of the dark ring were defined in a percentage of the patch area by analysing digital photographs. The in vitro data correlate mostly with the in vivo performance of the tested adhesives after 7 days. Accordingly, the probe tack test could be a helpful tool during the development of transdermal patches.