Modeling structure-function relationships for diffusive drug transport in inert porous geopolymer matrices

Area of Science:

• Materials Science
• Chemical Engineering
• Pharmaceutical Sciences

Background:

• Geopolymers offer potential as drug delivery vehicles due to their mechanical strength and tunable properties.
• Controlling geopolymer microstructure is crucial for regulating the diffusion and release of active pharmaceutical ingredients.

Purpose of the Study:

• To investigate the structure-function relationship of geopolymer drug delivery vehicles.
• To determine the effect of in-synthesis water content on geopolymer pore structure and drug transport.
• To enable predictable sustained release of potent substances.

Main Methods:

• Geopolymer synthesis with varied water content.
• Characterization using Scanning Electron Microscopy (SEM), N2 gas adsorption, and Mercury Intrusion Porosimetry.
• Mechanical testing (compression strength) and drug release/permeation studies with model drugs (Saccharin, Zolpidem).

Main Results:

• Mesoporous geopolymers with porosities ranging from 8% to 45% were successfully synthesized by adjusting water content.
• Effective diffusion coefficients for model drugs spanned two orders of magnitude (∼1.6-120 × 10(-8) cm(2)/s).
• Measured diffusion coefficients showed excellent agreement with theoretical values derived from pore-network modeling.

Conclusions:

• In-synthesis water content is a critical parameter for tailoring geopolymer pore structure and mechanical properties.
• Predictive modeling of drug permeation and release is achievable, facilitating material design for controlled drug delivery.
• This approach allows for the development of customized geopolymer formulations for sustained release of potent substances.