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Hindi Review Article
MECHANISMS, KINETICS AND MATHEMATICAL MODELLING OF TRANSDERMAL PERMEATION- AN UPDATED REVIEW
Abstract
Percutaneous absorption involves passive diffusion of substances through the skin. The mechanism of permeation can involve passage through the epidermis itself or diffusion through shunts, particularly those offered by the relatively ubiquitously distributed hair follicles and eccrine glands. While exceptions to the rule are acknowledged, it is now generally believed that the trans-epidermal pathway is principally responsible for diffusion across the skin. Far more often than not, the main resistance encountered along this pathway arises in the stratum corneum. The phenomenon of percutaneous absorption can be visualized as consisting of a series of steps in sequence: sorption of a penetrant molecule onto the surface layer of stratum corneum, diffusion through it and the viable epidermis, and finally, at the papillary layer of the dermis, the molecule is taken up into the microcirculation for subsequent distribution. Knowledge of skin permeation kinetics and Mathematical modeling is vital to the successful development of transdermal systems.
