Molecular mechanism of polymer dynamics and kinetics of solute transport in multicomponent systems

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Many new medicines are formulated by using multiple materials to provide patients with optimal therapeutic benefits. For example, once daily tablets are prepared by compressing drug powders with a large amount of polymers and other pharmaceutical additives. The additives, however, would influence water penetration and drug release from the tablets. In our laboratory we are also developing "intelligent" devices that can sense disease state thus adjusting the amount of drug given to patients. One of applications of this type of devices is controlling sugar levels in diabetic patients by regulating insulin delivery. In these devices, multicomponents are integrated in one system. To design such a device and once daily tablets with good quality and low cost, we must have thorough understanding of the properties of polymers and their interaction with other ingredients and solvent and have powerful computational tools for prediction of the performance of the tablets or the devices. However, prediction of molecular mechanism and drug release kinetics in such systems by modeling remains in the infant stage so far, which hinders the development of new pharmaceutical products for patients' need and reduction in the cost of health care. This project is thus proposed to investigate molecular mechanism of polymer dynamics and kinetics of solute transport (1) in polymer gels; (2) in heterogeneous swellable polymer matrices; (3) in environment-responsive polymeric composite membranes; and (4) to model and simulate solute transport in heterogeneous polymer systems. The polymer matrices will be prepared by casting mixtures of polymers and additives in a mold. The interaction of polymers with additives and solvents will be studied with various modern techniques including thermal and fluorescence analyses, molecular imaging and atomic force microscopy. The dynamics of polymer swelling, dissolution and drug diffusion will be evaluated by optical, electronic and infra-red microscopy, and laser scanning image analysis. The diffusion kinetics of a solute will be determined using a dissolution apparatus. Mathematical model will be developed and computer simulation will be performed to analyze the underlying mechanism and to predict drug release kinetics.