Dermatokinetics as an Important Tool to Assess the Bioavailability of Drugs by Topical Nanocarriers.

Background: Now-a-days, numerous nanocarrier-based drug products for topical applications are present in the market and number of similar products are being researched. To estimate the amount of drug delivery to skin, the scientists have now established techniques for separation of skin layers for the determination of drug concentrations. This forms the basis of pharmacokinetics of drug(s) in skin, i.e., dermatokinetics. However, dermatokinetic modeling of topical products is still a colossal challenge. Assessment of bioavailability helps in determination of safety and efficacy of topical formulations.

Objective: This article is an attempt to explore the usefulness and methodologies of dermatokinetics for nanocarriermediated topical delivery. It also showcases challenges in methodologies used for determination of dermatokinetic parameters along with advantages.

Method: All the articles (research and review) used for writing the manuscript were collected from various search engines like Science Direct, Google Scholar, PubMed and Eureka Select using keywords like dermatokinetics, novel drug delivery systems, bioequivalence, bioavailability and topical delivery.

Conclusion: As the methods used for determination of pharmacokinetics of oral and intravenous formulations are not useful for dermatokinetic assessment, various methods like tape stripping, microdialysis and vasoconstrictor assays are being used for dermatokinetic assessment. These methods are not only useful to determine the drug concentrations in skin layers, but can also be used to correlate the toxic effects of xenobiotics.