(674h) Phase Behavior and Aggregation Stability of Nano- and Micro-Particles Interacting With Gelling Polymeric Matrices

Development of effective delivery system for API requires a control of the structure and morphology of polymer matrix at the interface with API. The structure and morphology of such composites depend on many factors such as the method of formation, type of critical solution temperature, remoteness from the critical temperature, on the tendency of the film components to phase separation at the interface.

The introduction of nano- and micro-scale particles into polymer blends creates a large internal surface between the solid particles and the polymer, changing substantially the thermodynamic and mechanical properties of the polymer matrix Adsorption of polymers from solutions of their mixtures on solids plays an important role in the formation of API composite structures with evenly distributed i.e. non-aggregated particulate materials.

We present a comprehensive analysis of various types of aggregative behavior of API particulates embedded within the polymeric matrices. Examples include BCS Class II drugs interacting with cellulose ethers. The effect of the particles on the phase separation in forming polymeric networks may be also related to the selectivity of the component adsorption at the interface with a solid phase, leading to the redistribution of the system components between the bulk and the surface layers. We also present experimental data and theoretical models that predict transport properties and stability of API.