Highly efficient and low toxic skin penetrants composed of amino acid ionic liquids

Abstract

Herein, we introduce an amino acid ester (AAE) as a potent biocompatible counter ion to formulate ionic liquefied active pharmaceutical ingredients. By equimolar pairing of a non-steroidal anti-inflammatory drug (NSAID) as the anion and the AAE as the cation, the liquid formulation was feasibly obtained. In vitro drug permeation results using pig skin revealed a significant enhancement of the transdermal delivery of the ionic liquefied NSAIDs. The AAE showed much lower cytotoxicity to mouse fibroblast L929 cells when compared with that of conventional counter cations, indicating the significant potential of the AAE in the development of new ionic liquid drug formulations.