In vitro test of nicotine's permeability through human skin. Risk evaluation and safety aspects

Area of Science:

• Toxicology
• Dermal Absorption Studies

Background:

• Nicotine exposure can lead to intoxication via dermal absorption.
• Understanding nicotine's skin permeability is vital for developing effective safety protocols.

Purpose of the Study:

• To evaluate the significance of dermal nicotine absorption as an intoxication route.
• To assess the efficacy of safety procedures for handling nicotine spills on skin.

Main Methods:

• Utilized Franz' diffusion cells and an in vitro test model with human skin and glove materials.
• Applied pure nicotine and varying concentrations in water or ethanol.
• Simulated washing by removing nicotine after 3 or 5 minutes.
• Calculated permeation rate (flux) and lag time.

Main Results:

• Nicotine flux was concentration-dependent and non-linear in aqueous solutions, with highest flux at 50% w/w.
• Low concentration (1% w/w) aqueous nicotine solutions showed similar permeation to 100% nicotine.
• Ethanol solutions exhibited low flux, and pH influenced permeability, with acetic acid significantly reducing flux.
• Skin acted as a nicotine depot, with continued permeation after surface removal.
• Contact time critically affected absorption; 5 minutes resulted in higher concentrations than 3 minutes.

Conclusions:

• Dermal absorption is a critical route for nicotine intoxication.
• Immediate washing of spilled nicotine is essential due to skin's depot effect.
• Glove materials offer protection but require regular replacement.