Understanding drug release from poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) gels

Area of Science:

• Polymer science and drug delivery systems.
• Materials science and chemical engineering.

Background:

• Poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) copolymers, like Pluronic, form gels with potential applications in drug delivery.
• Understanding the release mechanisms of small molecular weight compounds from these polymer gels is crucial for optimizing drug delivery systems.

Purpose of the Study:

• To investigate the release mechanism of small molecular weight compounds from PEO-PPO-PEO polymer gels.
• To determine the factors controlling drug release, specifically the diffusion of solutes and water within the gel.
• To develop and validate a numerical model for predicting drug release from these polymer gels.

Main Methods:

• Experimental studies involving diffusion coefficient measurements of solutes and water in PEO-PPO-PEO gels.
• Development and numerical solution of a mathematical model to determine the controlling release mechanism.
• Utilizing a novel experimental setup to obtain drug release data for model validation.
• Investigating the effect of agitation speed on polymer gel dissolution rates.

Main Results:

• The primary mechanism controlling drug release from PEO-PPO-PEO gels is the rate of polymer dissolution.
• Diffusion at the gel/liquid interface contributes approximately 5% to the overall release, resulting in slightly non-linear release profiles.
• The developed numerical model accurately predicts drug release and can be adapted for various drugs and polymer concentrations.
• Agitation speed was found to significantly impact the dissolution rates of the polymer gels.

Conclusions:

• Drug release from PEO-PPO-PEO polymer gels is predominantly governed by polymer dissolution kinetics.
• A validated numerical model allows for the prediction of drug release, facilitating the design of controlled drug delivery systems.
• Further research can explore the influence of gel properties and external factors like agitation on drug release efficiency.