Investigation the binding and partition properties of azithromycin drug using drug-surfactant mixed micelles in the presence of trisodium citrate electrolyte

Abstract

The significance of mixed micelle in pharmaceutical industries is improving the binding and solubility of poorly water-soluble drugs. This work highlighted the effect of organic counterion (NAC) for improving the micellization association of zwitterionic (CAPB) and cationic drug (DPC) by surface tension measurements. The Corrin–Harkins (CH) approach assessed the CAPB, DPC and CAPB-DPC counterion binding values for DPC in the aqueous and NAC media at 25 °C. The counterion binding B for CAPB-DPC from αDPC 1.0–0.0 was found 0.536, 0.3801, 0.368, 0.355, 0.310 and 0.272 in the presence of NAC which indicated that DPC improved the counterion binding in the mixed micellar system. The Gibb’s free energy of micellization (ΔGmic°) were increased and became more negative, suggesting that the CAPB–DPC interaction was controlled by electrostatic interaction. Furthermore, the application of mixed micelle was utilized to enhance the binding constant (LogKb) and partition coefficient (LogKx) of the poorly water-soluble drug (AZI) in aqueous and NAC media at 25 °C using a UV spectrophotometer. From UV spectra, The LogKb and LogKx of AZI were lower in single micellar systems and higher in mixed micellar systems of CAPB-DPC. The maximum LogKb values at αDPC 0.4 were found 3.091, 3.233, 3.417, and 3.368 and LogKx values were found 4.749, 4.919, 5.087 and 5.049 in the presence of 0.0, 0.5, 3.0 and 20 mmol L−1 of NAC. AZI molecules are found in the palisade layer of mixed micelle when the DPC mole fraction is less than αDPC 0.6, while more than αDPC 0.6 causes steric hindrance, increasing hydrophobicity in the system. Furthermore, surfactant-drug mixed micelles could serve as poorly drug-solubilizing agents, as well as a multidrug delivery system in pharmaceutical applications.