Although absorption via the skin is highly dependent on the physicochemical properties of the drug substance, the properties of the device also play an important role. Unfortunately, prediction of in-vivo performance from in-vitro data is often disappointing! Thus, testing in humans remains the only really reliable method for assessing formulation properties.
For more than 10 years we have repeatedly performed all relevant types of clinical trials with Transdermal Therapeutic Systems:
Currently, the new European guidelines result in a strong requirement of experience and knowhow to adequately realise the studies in practice. So far, the methods and procedures are not entirely defined. However, SocraTec R&D has already established methods and standard operating procedures which reflect the new requirements and the experience of many years with such trials.