Amorphous Dispersion Speciation: Impact of Polymer Chemistry and Molecular Weight

Amorphous Dispersion Speciation: Impact of Polymer Chemistry and Molecular Weight

Wesley K. Tatum, Ph.D

Prinicpal Engineer

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Abstract:

‍Spray-dried dispersions (SDDs) are a key technology for enhancing bioavailability of poorly water-soluble compounds. SDD formulations enable increased intestinal absorption through two primary mechanisms: (1) increasing concentration of solvated drug leading to a higher driving force for passive diffusion through the intestinal epithelium, and (2) formation of colloidal species leading to increased rates of diffusion through the unstirred water layer and a rapid resupply of solvated drug at the surface of epithelial cells. While the former is achieved through the amorphous form, the latter is dependent on the formation and nature of colloidal species that are characteristic of SDD formulations.  

Our previous work has shown distinct differences in polymer speciation in a given biorelevant media as a result of concentration and polymer chemistry. The goal of the current study is to evaluate how molecular weight and flexibility influences the partitioning of drug molecules into the polymer colloids.

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Learning Objectives:

Understand the importance of speciation in amorphous solid dispersions

Understand the differences between polymer colloids formed from different polymers used in amorphous dispersions

Understand how molecular properties can influence the interactions between drugs and polymers