(51g) Application of Novel Ionic Liquids for Cutaneous Drug Delivery

The skin is the largest organ in the body. It provides a compliant interface for needle-free drug delivery, while avoiding major degradative pathways associated with the GI tract. These result in improved patient compliance and sustained and controlled release compared to other standard delivery methods. Concurrently, for the treatment of skin related diseases (e.g. bacterial infection, skin cancer, psoriasis, atopic dermatitis, etc.) cutaneous application provides targeted delivery to the diseased site, allowing the use of more potent therapeutics with fewer systemic side effects. Unfortunately, the outer layer of the skin – the stratum corneum (SC) – presents a significant barrier to most foreign material. This is particularly true for large hydrophilic molecules (>500Da), which must partition through tortuous lipid channels in the SC to penetrate deep tissue layers where the majority of skin-related diseases reside.

Interestingly, over the last few decades ionic liquids (ILs) have emerged as a burgeoning class of designer solvents. Indeed, ILs have been proven beneficial for use in industrial processing, catalysis, pharmaceuticals, and electrochemistry to name a few. The ability to modulate either the cation or anion individually presents an advantageous framework for tuning secondary characteristics without sacrificing the primary function of the IL. We report, for the first time, the use of novel ILs for cutaneous drug delivery. The ILs employed were rationally designed by incorporating known chemical penetration enhancers (CPEs), and retained tunability of potential secondary properties (e.g. viscosity, hydrophobicity/hydrophilicity, antibacterial/antibiofilm activity, thermal stability, etc.) through manipulation of ion pairing. The work presented shows the potential of ILs for cutaneous drug delivery.