Systemic Topical Drug Delivery: US Regulatory Perspectives on Product Development, Biopharmaceuticals and Clinical Pharmacology
Topical Drug Delivery which encompass both dermal (local) and transdermal (systemic) products is one of the most exciting and challenging areas of pharmaceutical research. Traditionally, topical drug delivery systems denote formulations that are intended to deliver drugs locally rather than systemically. These products differ from transdermal delivery systems, which are designed for drugs to penetrate through the skin and provide systemic action. Whether it is topical or transdermal, effectiveness of the formulation depends on the release of the active drug from its dosage form to the skin surface. Once the drug is presented to the skin surface, either it stays mostly on the skin surface or penetrates through the stratum corneum to other cutaneous layers all the way up to systemic circulation to manifest its pharmacological action depending upon the location of the disease to be treated.