Linker-Based Lecithin Microemulsions as Drug Delivery Vehicles

This invention is a novel formulation for biocompatible microemulsions for use as delivery vehicles for active ingredients in transdermal, topical and oral delivery. The formulation is based on five basic ingredients: lecithin (extracted from soybean or other source); a lipophilic additive such as long change alcohol or long chain fatty acid, monoglyceride, or sorbitol ester; a hydrophilic additive containing C6-C9 fatty acids partially saponified; a C8-C20 fatty acid ester; and water. Particular combinations of these ingredients, at specific ratios, yield thermodynamically stable microemulsions capable of increasing the solubility (in isotonic solutions) of hydrophobic drugs such as lidocaine, and alpha-tocopherol acetate by more than 20 fold.


A key challenge in developing an effective transdermal delivery system for hydrophobic compounds, involves the creation of formulations that balance high permeability of the stratum corneum barrier with minimal skin irritation. Because of their small droplet size, high oil solubilization capacity and large interfacial area, microemulsions have demonstrated a greater adsorption/penetration of hydrophobic actives when compared to conventional emulsions. Unfortunately, toxicity issues associated with the types of surfactants and cosurfactants used in the past have limited their application, especially in pharmaceutical as well as cosmeceutical formulations.


  • Efficient delivery of hydrophobic active ingredients
  • Higher solubility
  • Increased absorption and permeation of active ingredients through epithelial tissue, thus producing an extended active release effect
  • Significantly less cytotoxic

IP STATUS: Granted patents in multiple jurisdictions





Colloids , Complex fluids , Dermal applications , Drug Delivery , Formulation engineering , Cosmeceutical

VPRI Contact

Ian Stewart

Innovations & Entrepreneurship Manager
Innovations & Partnerships Office (IPO)
(416) 946-7734

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