Dynamics of Interfacial Diffusion Control in Amphiphilic Lipid-Coated Micro-Particles for Stochastic Release Systems

TL;DR

This study investigates how amphiphilic lipid coatings on micro-particles influence the diffusion-controlled release of hydrophilic solutes, revealing that nanoscale lipid organization affects release dynamics and systemic absorption.

Contribution

It introduces a soft matter perspective to model interfacial diffusion in coated micro-particles, linking microstructure to macroscopic release behavior.

Findings

Coated particles show delayed systemic appearance of solutes.

Late time serum levels are higher for coated particles, indicating reduced diffusivity.

Diffusion barrier physics explains the broadened release-time distribution.

Abstract

The release of hydrophilic solutes from micron scale particulate formulations can be understood as an interfacial transport problem in which diffusion across a heterogeneous amphiphilic coating competes with dissolution and convective removal in the surrounding medium. Here we reinterpret a glycerin fatty acid ester (GFAE) coated thiamine (vitamin B1) micro particle formulation as a condensed matter system: a soft matter core shell geometry whose effective permeability is set by the nanoscale organization of amphiphilic lipids at the interface. Using in vivo time course serum measurements in mice as a proxy for a stochastic sink, we compare the coated formulation (UTEV) with a composition matched uncoated comparator (UMFG). Early time systemic appearance is similar, whereas late time levels are enhanced for the coated particles, implying a reduced effective interfacial diffusivity and a broadened release-time distribution. We discuss the results in terms of diffusion barrier physics, heterogeneous interfacial energetics, and coarse grained transport models that map microstructural coating parameters to macroscopic persistence (AUC).