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Research Abstracts Online
January 2008 - March 2009

University of Minnesota Twin Cities
School of Pharmacy
Department of Pharmaceutics

PI: Raj G. Suryanarayanan

Structures, Stability, and Behavior of Hydrates; Water Sorption and Desorption in Pharmaceutical Materials

These researchers are using MSI resources for three projects. In the first, they are investigating hydrates, a form that appears in numerous compounds of pharmaceutical interest. Their use in dosage forms poses a unique challenge since dehydration during processing or storage can have profound implications on the stability and performance of the dosage form. These researchers are investigating the mechanism of dehydration of dibasic calcium phosphate dihydrate from a structural viewpoint. They use molecular modeling to obtain information on lattice energies of the hydrate, anhydrate, and possible intermediate hydrates. These structural features can provide insights into the phase behavior of dicalcium phosphate dihydrate.

The second project focuses on the use of thiamine hydrochloride as a model compound to understand the stability and behavior of nonstroichiometric hydrates that pose considerable challenges in solid-state characterization. The researchers are trying to understand the physical stability differences between hydrates of thiamine hydrochloride using single-crystal structures of the two hydrate forms it exists in.

The third project uses molecular modeling to understand water sorption-desorption in amorphous pharmaceutical materials at the molecular level, and comparing the model with experiment results. Molecular dynamic simulations of water sorption-desorption of the amorphous system will also provide an in-depth knowledge of free volume theory. This research will be applicable to increasing the stability and shelf-life of pharmaceutics.

Group Members

Paroma Chakravarty, Graduate Student
Ajay Saxena, Research Associate
Venugopal Rao Vangala, Research Associate