Cations of amino acid alkyl esters conjugated with an anion from the group of NSAIDs – As tunable pharmaceutical active ionic liquids
Joanna Klebeko, Paula Ossowicz‐Rupniewska, Anna Nowak, Edyta Kucharska, Łukasz Kucharski, Wiktoria Duchnik, Łukasz Struk, Adam Klimowicz, Ewa Janus
Abstract
Herein, we investigated the effect of pairing the L-amino acid alkyl (propyl, isopropyl, or butyl) ester on the formation of API-ILs. The novel salts of NSAIDs (non-steroidal anti-inflammatory drugs) obtained from biodegradable cations were synthesised and characterised by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), and X-ray powder diffraction (XRD) methods. The influence of structure counterions for APIs from the NSAIDs group on their physicochemical properties was studied in detail. The comprehensive effects of cation structure on skin permeation, accumulation, and antioxidant activity of API-ILs were also evaluated. These results demonstrated that L-amino acid alkyl esters can be successfully used to synthesise API-ILs further used in topical formulations with anti-ageing, anti-inflammatory, or photoprotective effects.