Blending induced variations in Poloxamer's/Pluronic's® gelation: Thermodynamic and rheological perspectives

Abstract

Amphiphilic block copolymers (ABCs) are currently significant in pharmaceutical sciences because of their specific capability to develop various structures that are highly efficient for drug delivery. Poloxamers, sometimes referred to as Pluronic's®, are very remarkable due to their exceptional biocompatibility and adaptability. Poloxamers are a type of nonionic triblock copolymers that consist of hydrophilic poly(ethylene oxide) (PEO) and hydrophobic poly(propylene oxide) (PPO) organized in a sequence of PEO-PPO-PEO. Due to this arrangement, they are able to encapsulate drugs within their hydrophobic core and self-assemble into micelles in aqueous solutions beyond certain critical micelle concentrations (CMC) and temperatures (CMTs). Understanding and optimising these systems requires a thorough comprehension of the micellisation process and its thermodynamics, which encompass the changes in free energy, enthalpy, and entropy. Differences in molecular weight and the proportion of PEO to PPO lead to the formation of several different poloxamers, each possessing unique properties and uses. This paper examines the process of micellisation, the structure of micelles, thermodynamic factors, and the importance of critical micelle concentration (CMC) and critical micelle temperature (CMT). It emphasizes the significance of these parameters in pharmaceutical formulations and drug delivery systems.