The role of viscosity on skin penetration from cellulose ether-based hydrogels.

Background: The rheological properties of dermal drug delivery systems are of importance when designing new formulations. Viscosity not only affects features such as spreadability and skin feel, but may also affect the skin penetration of incorporated actives. Data on the latter aspect are controversial.

Penetration monitoring of drugs and additives by ATR-FTIR spectroscopy/tape stripping and confocal Raman spectroscopy - A comparative study.

Vibrational spectroscopy is a useful tool for analysis of skin properties and to confirm the penetration of drugs and other formulation compounds into the skin. In particular, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and confocal Raman spectroscopy (CRS) have been optimised for skin analysis. Despite an impressive amount of data on these techniques, a comparative methodological assessment for skin penetration monitoring of model substances is still amiss.