Journal of Colloid and Interface Science, Vol.552, 287-294, 2019
Arginine-based cationic surfactants: Biodegradable auxiliary agents for the formation of hydrophobic ion pairs with hydrophilic macromolecular drugs
Working hypothesis: It was the hypothesis of this study that esters of arginine (Arg) with medium and long chain aliphatic alcohols are biodegradable and less cytotoxic than well-established cationic surfactants being used for hydrophobic ion pairing (HIP) with hydrophilic macromolecular drugs. Experiments: Arg was linked to nonan-1-ol and hexadecan-1-ol (C-9 and C-16) via an ester linkage. The newly formed Arg-nonyl ester (ANE) and Arg-hexadecanoyl ester (AHE) surfactants were evaluated regarding critical micelle concentration (CMC) using pyrene fluorescent method, cytotoxicity on human colorectal adenocarcinoma-derived cells (Caco-2) and biodegradability at the concentrations of 2.5 and 5 mg/mL using 2500 N-alpha-benzoyl-L-arginine ethyl ester hydrochloride (BAEE) units/mL of trypsin. Furthermore, in order to evaluate their potential for HIP, heparin and daptomycin were used as model polysaccharide and peptide drugs, respectively. Findings: Chemical structures of ANE and AHE surfactants were confirmed by FTIR, H-1 NMR, and LC-MS. CMC of ANE was 7.5 mM and CMC of AHE was 2 mM. Arg-surfactants were not cytotoxic below their CMC. At CMC and above CMC, ANE was significantly (P < 0.05) more cytotoxic than AHE. ANE in both concentrations was degraded >98% within 48 h. The degradation of AHE at lower concentration was >97% and about 50% at higher concentration. Arg-surfactants were able to efficiently precipitate heparin and daptomycin from corresponding aqueous solutions. Conclusion: Arg-surfactants being biodegradable and less toxic seems to be a promising alternative to well-established cationic surfactants for the formation of hydrophobic ion pairs (HIPs) with hydrophilic macromolecular drugs. (C) 2019 Elsevier Inc. All rights reserved.