Effect of vehicles and sodium lauryl sulphate on xenobiotic permeability and stratum corneum partitioning in porcine skin

Abstract

Dermal contact with potentially toxic agricultural and industrial chemicals is a common hazard encountered in occupational, accidental spill and environmental contamination scenarios. Different solvents and chemical mixtures may influence dermal absorption. The effects of sodium lauryl sulphate (SLS) on the stratum corneum partitioning and permeability in porcine skin of 10 agricultural and industrial chemicals in water, ethanol and propylene glycol were investigated. The chemicals were phenol, p-nitrophenol, pentachlorophenol, methyl parathion, ethyl parathion, chlorpyrifos, fenthion, simazine, atrazine and propazine. SLS decreased partitioning into stratum corneum from water for lipophilic compounds, decreased partitioning from propylene glycol and did not alter partitioning from ethanol. SLS effects on permeability were less consistent, but generally decreased permeability from water, increased permeability from ethanol and had an inconsistent effect on permeability from propylene glycol. It was concluded that, for the compounds tested, partitioning into the stratum corneum was determined by the relative solubility of the solute in the donor solvent and the stratum corneum lipids.Permeability, however, reflected the result of successive, complex processes and was not predictable from stratum corneum partitioning alone. Addition of SLS to solvents altered partitioning and absorption characteristics across a range of compounds, which indicates that partition coefficients or skin permeability from neat chemical exposure should be used with caution in risk assessment procedures for chemical mixtures.

Effects of eight vehicles on transdermal lidocaine penetration in sheep skin in vitro

“…A possible reason for the increased lag time associated with the DGME vehicle is dehydration of the skin, an effect also found with alcohol‐based formulations. While alcohol‐based formulations were found to be more effective at depositing abamectin in ovine skin (Baynes, ), the organic solvent ethanol was not chosen as a vehicle in this study because it dehydrates and desiccates skin (Mills et al ., ; Thomas & Panchagnula, ; van der Merwe & Riviere, ). A study in rat skin, using 100% ethanol compared with ethanol and water combinations, found an increase in lag time for 100% ethanol, which was associated with dehydration of the epidermis.…”