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O: Fachverband Oberflächenphysik

O 18: Solid-liquid Interfaces II

O 18.11: Vortrag

Montag, 31. März 2014, 18:30–18:45, WIL A317

Molecular Dynamics Simulations of the Dissolution of Lactose Crystals — •Berna Dogan, Julian Schneider, and Karsten Reuter — Technische Universität München, Germany

Apart from its widespread use in food industry, Lactose is commonly applied in the pharmaceutical industry as an excipient for drug formulations. This application demands an efficient dissolution of its crystalline alpha lactose monohydrate (alpha-LM) phase to enable a fast uptake of the active pharmaceutical ingredient. Seeking for an understanding of the underlying molecular porcesses, we aim at complementing the available dissolution experiments with force-field molecular dynamics (MD) simulations of the alpha-LM/water interface at the atomistic level.

At near-equilibrium conditions, dissolution is expected to primarily take place at kink sites within step edges. The dissolution velocity of a step edge can then be derived from the kink free energy, as well as the rate constant of the molecular detachment process [1]. Instead of approximating the defect free energies by potential energy differences of rigid crystal arrangements [1], we aim at a precise calculation, including entropic contributions and explicit solvation. We, therefore, present a modification of binding free energy methods of molecular ligand/receptor complexes towards an application to surface defects. Moreover, we show how the molecular rate constants can be calculated at the same level of precision from accelerated molecular dynamics simulations.

[1] R. C. Snyder and M. F. Doherty: Proc. R. Soc. A, 465, 1145, (2009)