An investigation of the effect of surfactants on transdermal permeation.

Cumming, K. Iain

Abstract

The aim of this study was to investigate the direct effects of surfactants on the stratum corneum, and thus propose mechanisms of action for these compounds as penetration enhancers. The main methods used in the study were: determination of the permeability of neonatal rat stratum corneum to propan-2-ol; differential scanning calorimetry (DSC); Fourier transform infrared spectroscopy (FTIR); and thin layer chromatography (TLC); with the physical methods being used to elucidate structural changes in the stratum corneum. All of the surfactants, except for the polysorbates, caused highly significant increases in the permeability of the stratum corneum following pretreatment. The work with sodium lauryl sulphate (SLS) showed that the increase in permeability was time and concentration dependent. Studies on a series of sodium carboxylates identified that the alkyl chain length had a significant effect on the permeability increase, with the C12 member of the series showing the largest increase. Cationic and nonionic surfactants also showed structure dependent changes in the permeability which have been discussed in the thesis. The physical techniques proved valuable in detecting changes in the structure of the stratum corneum, especially for changes in lipid structure. Both DSC and FTIR were able to show changes in lipid structure which was associated with increases in permeability. DSC appeared to be more sensitive to these lipid changes than FTIR, and a good correlation was obtained between the decrease in lipid transition temperatures (detected by DSC) and the enhancement ratio (ER). This indicated that DSC may prove useful as a screen test for this type of penetration enhancers, where the effects are on the intercellular lipids. The TLC data proved valuable in assessing the role of lipid extraction as a mechanism in the penetration enhancement detected. The effects of the surfactants on the structure of the stratum corneum have been discussed in detail, and mechanisms have been proposed for the action of these compounds as penetration enhancers. A number of proposals have been made for further work, which would lead to an even better understanding of the mechanisms involved.

Citation

CUMMING, K.I. 1994. An investigation of the effect of surfactants on transdermal permeation. Robert Gordon University, PhD thesis. Hosted on OpenAIR [online]. Available from: https://doi.org/10.48526/rgu-wt-2807341

• Thesis Type: Thesis
• Deposit Date: Jul 3, 2025
• Publicly Available Date: Jul 3, 2025
• DOI: https://doi.org/10.48526/rgu-wt-2807341
• Public URL: https://rgu-repository.worktribe.com/output/2807341
• Award Date: Oct 31, 1994