Incorporation of the poorly soluble drug cefixime inside the micellar core of conventional and gemini surfactants

This work reports the physicochemical behavior of the antibiotic drug, cefixime (CEF) in the presence of cetyl trimethyl ammonium bromide (CTAB), dodecyl trimethyl ammonium bromide (DTAB), dodecyl ethyl dimethyl ammonium bromide (DDAB), sodium dodecyl sulfate (SDS), sodium deoxy cholate (NaDOC), Tween 80, Tween 20, and tyloxapol as well as cationic gemini surfactants, viz., 12-3-12 and 16-3-16. Drug-surfactant interaction studies were investigated using spectroscopic studies (UV-Vis and fluorescence) to evaluate the binding constant (K-b) and quenching constant (K-sv) values. Thermodynamic parameters, viz., the free energy (Delta G0(m)), enthalpy (Delta H0(m)), and entropy (Delta S0(m)), were calculated using conductivity measurements. A steady increase in solubility was observed with increasing surfactant concentrations. Solubility studies confirm the high solubility of CEF in the presence of gemini surfactants. In addition, UV-Visible and fluorescence studies were also done to investigate the interactions of CEF with serum albumin (bovine serum albumin; BSA) in the presence of surfactants. Circular dichroism (CD) studies were carried out to determine the effect of CEF-surfactant formulations on the structures of transport proteins (BSA, human serum albumin; HSA) and structural proteins (collagen). Gemini surfactants showed stronger associations with CEF and were found to be the most effective and compatible solubilizing media for CEF in comparison with conventional surfactants.