IV-IVC for topically applied preparations-a critical evaluation

To obtain an IV-IVC for a topically applied drug product is a difficult challenge. However, some success has been achieved in showing a relationship between the drug release and PD and/or DPK measurement. Interestingly, one of the in vitro rheological properties was found to relate to the observed PD and DPK response for Clobetasol dipropionate products. Different rheological properties of the two formulation products explained the difference in DPK results obtained by two laboratories for the same tretinoin gel products. In the scientific arena, it is difficult to obtain a classical IV-IVC even for orally administered products and is more so difficult for topically administered drug products.