The encapsulation of hydrophobic drugs in Pluronic F127 micelles: the effects of drug hydrophobicity, solution temperature and pH

TL;DR

This study investigates how drug hydrophobicity, temperature, and pH influence the encapsulation and release of hydrophobic drugs in Pluronic F127 micelles, using experimental techniques like cryo-SEM, DLS, and fluorescence.

Contribution

It provides new insights into how environmental factors affect drug encapsulation efficiency and micelle stability in Pluronic F127 systems.

Findings

Drug uptake reduces critical micellization temperature.

Micelle size and polydispersity increase with decreasing temperature and drug presence.

High pH causes micelle rupture and drug release.

Abstract

Three drugs, Ibuprofen, Aspirin and Erythromycin, are encapsulated in spherical Pluronic F127 micelles. The shapes and the size distributions of the micelles in dilute, aqueous solutions, with and without drugs, are ascertained using cryo- Scanning Electron Microscopy and Dynamic Light Scattering (DLS) experiments, respectively. Uptake of drugs above a threshold concentration is seen to reduce the critical micellization temperature of the solution. The mean hydrodynamic radii and polydispersities of the micelles are found to increase with decrease in temperature and in the presence of drug molecules. The hydration of the micellar core at lower temperatures is verified using fluorescence measurements. Increasing solution pH leads to the ionization of the drugs incorporated in the micellar cores. This causes rupture of the micelles and release of the drugs into the solution at the highest solution pH value of 11.36 investigated here and is studied using DLS and fluorescence spectrocopy.