(724g) Temperature Dependent Release Kinetics from Glucan Microparticles

Recent advances in particle technology allowed introducing several methods for the manufacturing of particles in nano- and microscale size. They can be prepared via classical physico-chemical methods but also using an alternative bio-inspired approach by using the call walls of existing microorganisms, preserving their shape, size and biodegradability.

Glucan microparticles are purified Saccharomyces cerevisiae (or baker’s yeast) cell walls. They are hollow and porous 2–5 μm microspheres. The 1,3-β-glucan outer shell can provide receptor-mediated uptake by phagocytic cells expressing β-glucan receptors. They can be used as drug carriers for the macrophage drug delivery.

In the present work, glucan microparticles have been isolated from Saccharomyces cerevisiae and purified. Subsequently, the stability and agglomeration kinetics of glucan microparticles was measured. The release kinetics of a model substance (vitamin B12) loaded into the microparticles was investigated at temperatures systematically ranging from 10 °C to 60 °C and found to be a non-linear function of temperature. This behaviour was explained by a glass transition of β-glucan, measured with temperature-dependent FT-IR and DSC. The temperature-dependent diffusion coefficients of vitamin B12 across the glucan wall were calculated from the experimental data using a mathematical model. Finally, the glucan particles were modified by a magnetic resonance imaging (MRI) contrast agent to allow simultaneous visualization of their spatial distribution by MRI and temperature-triggered drug release, paving the way towards potential applications in theranostics.