Molecular dynamics simulations of glycine crystal-solution interface

Area of Science:

• Crystallization science
• Materials science
• Biochemistry

Background:

• Glycine is a crucial amino acid with significant pharmaceutical applications.
• Controlling the growth of alpha-glycine crystals via solution crystallization is vital for pharmaceutical development.
• Understanding seeded growth dynamics is essential for optimizing crystal formation processes.

Purpose of the Study:

• To investigate the seeded growth of alpha-glycine crystals from aqueous solutions using molecular dynamics simulations.
• To analyze the dissolution behavior of the (110) face of alpha-glycine crystals.
• To determine the influence of temperature and concentration on glycine diffusion and hydrogen bonding at the crystal-solution interface.

Main Methods:

• Molecular dynamics simulations were employed to model the (110) face of alpha-glycine in contact with an aqueous glycine solution.
• The crystal-solution interface dynamics were tracked by monitoring density gradients.
• Diffusion coefficients were calculated at various temperatures and concentrations, and hydrogen bond formation was analyzed using radial distribution functions.

Main Results:

• Simulations showed that alpha-glycine crystals dissolve over time at a decreasing rate.
• Glycine diffusion coefficients near the (110) face were quantified and compared to bulk values.
• Analysis revealed a correlation between hydrogen bond formation at the interface and altered diffusion coefficients.

Conclusions:

• The study provides fundamental insights into the dissolution and interfacial behavior of alpha-glycine crystals.
• Hydrogen bonding plays a critical role in modulating glycine diffusion at the crystal-solution interface.
• These findings contribute to a deeper understanding of solution crystallization processes for pharmaceutical applications.