An investigation on the hydrophobic binding stability of Azithromycin to the hydrocarbon chains of Tween: Based on micellization thermodynamics

Abstract

Based on micellization thermodynamics, the difference in hydrophobic binding stability between Azithromycin and the hydrocarbon chain of Tween was investigated. Initially, the critical micelle concentration (CMC) of AZM-loaded Tween micelles was determined by measuring surface tension, followed by subsequent analysis and discussion of the associated parameters of micellization thermodynamics. The findings indicated that AZM-loaded Tween 20 and AZM-loaded Tween 80 micelles both exhibited a lower CMC value, enhanced stability at the air/water interface, and a more pronounced tendency towards micellization. This suggested that Azithromycin exhibited a stronger affinity towards the hydrophobic hydrocarbon chains of Tween 20 and Tween 80, leading to a more robust hydrophobic binding between them, thereby promoting the formation of AZM-loaded micelles. Subsequently, the transmittance, particle size, and in vitro release of each micelle system were assessed. The findings demonstrated that both AZM-loaded Tween 20 and AZM-loaded Tween 80 micelles exhibited excellent physical stability. Furthermore, in terms of antibacterial activity, AZM-loaded Tween 20 and AZM-loaded Tween 80 micelles exhibited stronger antibacterial efficacy. In summary, the variation in the hydrocarbon chain of Tween exerts an influence on the stability of the hydrophobic binding between Tween and Azithromycin, consequently impacting the pertinent attributes of drug-loaded micelles. This finding offers a valuable point of reference for the investigation of hydrophobic drug micelles in academic research.