Therapeutic delivery systems: a new approach to evaluate physical properties of transdermal delivery systems (TDS)

In the present paper a new methodological setup to objectify the parameters adhesiveness and adhesive strengths of Transdermal Delivery Systems is presented. The setup includes 6 steps: Evaluation of skin type, application of the patch by a pneumatic device, evaluation of detached area of the patch by planimetric means, assessment of the adhesive strength by a patch removal unit, evaluation of reddening of the skin, and examination for water uptake of the skin layers by high resolution ultrasound. Each step is described individually. Further problems arising from studies performed with this methodological setup concerning possible adhesive-drug interactions as well as uncorrelated drug behavior to nondetached area of the patch with regard to the pharmacokinetic profile are discussed.