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Updated: Aug 24, 2026

Environmental Dynamic Mechanical Analysis to Predict the Softening Behavior of Neural Implants
Published on: March 1, 2019
Modeling and monitoring of polymorphic transformations during the drying phase of wet granulation
Tiffani D Davis1, Garnet E Peck, Joseph G Stowell
1Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, Indiana 48908-2091, USA.
Purpose:
The purpose of this work was to monitor polymorphic transformations of glycine during the drying phase of a wet granulation and model the polymorphic conversions using a time-based reconciliation model.
Methods:
Near-infrared spectroscopy (NIR) was used for quantitation of polymorphs, and X-ray powder diffraction (XRPD) was used for qualitative analysis of polymorphs.
Results:
The data show that the faster the granulation was dried, the more kinetic trapping of the metastable alpha-glycine polymorph, as predicted by reconciliation of the time scales of both the drying rate and the rate of the solution-mediated conversion.
Conclusions:
By knowing basic properties of the drug substance (solubility of the polymorphic forms and the rate of the solution-mediated conversion), processing conditions, such as the drying rate, can be adjusted to anticipate and prevent potential polymorphic transformations.

