Synthesis, Characterization and Cytotoxicity Evaluation of an Oleic Acid Derived Novel Bicephalous Dianionic Surfactant

A novel oleic acid derived bicephalous dianionic surfactant disodium (Z) 3,3'-(oleoylazanediyl)dipropanoate containing one hydrophobic carbon chain and two hydrophilic head groups was synthesized, characterized and evaluated for cytotoxicity for the purpose of introducing a new biocompatible surfactant. The head group 3,3'-azanediyldipropanoate was synthesized through Michael addition of methyl acrylate to benzylamine and subsequent reductive debenzylation with Pd/C, H-2 and was condensed with an oleic acid moiety via amide bond formation. Ester groups at the periphery were hydrolyzed using acetyl chloride-water and the diacid formed was neutralized with sodium bicarbonate to obtain the desired surfactant. The CMC was determined by conductometry, log P (octanol/water) by ChemSW software and the hydrophilic-lipophilic balance (HLB) by the Davies method and ChemSW. In vitro cytotoxicity study was performed using sulforhodamine B assay and the in vivo skin irritation study was performed on male New Zealand white rabbits as per OECD guideline 404. The CMC was found to be 1.9 mm/l which was almost half of the CMC of sodium oleate. The Log P (octanol/water) value of -3.87 and the HLB values of 35.22 and 34.46 by the Davies method and ChemSW software respectively revealed the hydrophilic nature of the surfactant. The surfactant did not exhibit any cytotoxicity at any of the concentrations tested and was found to be non-irritating by in vivo skin irritation studies. The findings of the present work suggest that the synthesized novel bicephalous dianionic surfactant is a safe and biocompatible excipient. It has the potential to be an attractive alternative to linear and gemini surfactants for applications in biological studies and pharmaceutical drug delivery systems.