Evaluation of skin absorption of drugs from topical and transdermal formulations

ABSTRACT The skin barrier function has been attributed to the stratum corneum and represents a major challenge in clinical practice pertaining to cutaneous administration of drugs. Despite this, a large number of bioactive compounds have been successfully administered via cutaneous administration because of advances in the design of topical and transdermal formulations. In vitro and in vivo evaluations of these novel drug delivery systems are necessary to characterize their quality and efficacy. This review covers the most well-known methods for assessing the cutaneous absorption of drugs as an auxiliary tool for pharmaceutical formulation scientists in the design of drug delivery systems. In vitro methods as skin permeation assays using Franz-type diffusion cells, cutaneous retention and tape-stripping methods to study the cutaneous penetration of drugs, and in vivo evaluations as pre-clinical pharmacokinetic studies in animal models are discussed. Alternative approaches to cutaneous microdialysis are also covered. Recent advances in research on skin absorption of drugs and the effect of skin absorption enhancers, as investigated using confocal laser scanning microscopy, Raman confocal microscopy, and attenuated total reflectance Fourier-transform infrared spectroscopy, are reviewed

Alterations in circulating thyroid hormones and thyroxine binding globulin in chronic alcoholism

The present study concerns eighteen chronic alcoholics with minimal liver damage. A significant reduction in total serum T4 with an accompanying drop in circulating TBG was observed in these otherwise euthyroid patients. During alcohol withdrawal, we observed a rapid increase in T4 and TBG into the normal range. We suggest that the fall in the level of circulating thyroxine-binding globulin is related to a defect in its synthesis or secretion by the liver due to ethanol consumption. Caution is recommended in the interpretation of thyroid function tests in chronic alcoholics.SCOPUS: ar.jFLWNAinfo:eu-repo/semantics/publishe