Non-ionic surfactant effects on hairless mouse skin permeability characteristics

Area of Science:

• Dermatology and Pharmaceutical Sciences
• Materials Science and Engineering

Background:

• Transdermal drug delivery aims to improve therapeutic efficacy and patient compliance.
• Stratum corneum lipid bilayers and corneocyte structures present significant barriers to drug permeation.
• Non-ionic surfactants are explored as penetration enhancers due to their amphipathic nature.

Purpose of the Study:

• To investigate the influence of polyethoxylated non-ionic surfactants on methyl nicotinate transport across hairless mouse skin in vitro.
• To identify structural characteristics of surfactants that correlate with enhanced skin permeation.
• To elucidate potential mechanisms by which surfactants facilitate methyl nicotinate penetration.

Main Methods:

• In vitro permeation studies using standard two-compartment diffusion cells.
• Hairless mouse skin as the biological barrier.
• Systematic variation of surfactant hydrophobic (alkyl chain length, branching) and hydrophilic (ethylene oxide chain length) components.
• Quantification of methyl nicotinate flux.

Main Results:

• Surfactants with linear alkyl chains ( > C8) and shorter ethylene oxide chains ( < E14) significantly increased methyl nicotinate flux.
• Branched or aromatic hydrophobic moieties rendered surfactants ineffective.
• Polyoxyethylene (10) lauryl ether (Brij 36T) demonstrated maximum flux enhancement.
• A C12 surfactant exhibited maximal activity, suggesting structural specificity.

Conclusions:

• The efficacy of polyethoxylated non-ionic surfactants as skin penetration enhancers is highly structure-dependent.
• Surfactants likely enhance permeation by disrupting stratum corneum intercellular lipids and/or interacting with intracellular keratin.
• Polyoxyethylene (10) lauryl ether represents a promising candidate for enhancing transdermal delivery of methyl nicotinate.