Dynamics and Crystallization in Pharmaceuticals and Energetic Materials

Amorphous solid-like materials, often referred to as glasses, form an important new area of materials science in developing novel materials through physical processes rather than chemical synthesis. For example, in the case of pharmaceutical materials the crystalline state is often only very weakly soluble in body fluids (saliva, stomach acid, intestinal tract) and this means that high doses of an expensive drug may need to be administered to the patient. On the other hand, when such a material is formed as an amorphous glassy substance the solubility goes up and the drug bioavailability can also be increased. The difficulty is that often the amorphous material will recrystallize during storage, thus losing its higher solubility benefits. In the case of energetic materials, the problem is not one of solubility but rather of safety where the amorphous energetic material is expected to be more stable during storage, e.g., on-board a destroyer or in an arsenal, thus reducing the chances of an unsafe explosion. In both instances we are studying the ability to make stable amorphous glasses from systems that would normally be found in a crystalline state. The work involves studies of the crystallization kinetics and impact of nanoconfinement on the crystallization and other performance aspects of the materials. The work on the pharmaceutical materials is being carried out in collaboration with Dr. P. Chakravarty at Genentech and Prof. R. Suryanarayanan at the University of Minnesota. The work at TTU is joint with Prof. S.L. Simon.

 

Some Publications

1. S. Cheng and G.B. McKenna*, "Nanoconfinement Effects on the Glass Transition and Crystallization Behaviors of Nifedipine," Molecular Pharmaceutics, 16, 856-866 (2019).

2. M. Mehta, G.B. McKenna and R. Suryanarayanan*, "Molecular mobility in glassy dispersions: Physical Stability Implications,"Journal of Chemical Physics, 144, 204506 (2016).

3. M. Mehta, V. Ragoonanan, G. B. McKenna, and R. Suryanarayanan*, "Correlation between Molecular Mobility and Physical Stability in Pharmaceutical Glasses," Molecular Pharmaceutics, 13, 1267-1277 (2016).

4. N. Shamim, Y.P. Koh, S.L. Simon, and G.B. McKenna*, "The glass transition of trinitrotoluene (TNT) by flash DSC," Thermochimica Acta, 620, 36-39 (2015).

5. R. Bari, Y. P. Koh, G. B. McKenna* and S. L. Simon*, "Decomposition of HMX in solid and liquid states under nanoconfinement," Thermochimica Acta, 686, 78542 (2020).

6. R. Bari, A.A. Denton, Z.T. Fondren, G.B. McKenna* and S.L. Simon*, "Acceleration of decomposition of CL‑20 explosive under nanoconfinement," Journal of Thermal Analysis and Calorimetry, 140, 2649-2655 (2020).

 

Funding

• National Science Foundation. Civil, Mechanical and Manufacturing Innovation (CMMI).
• Picatinny Arsenal through the Defense Ordnance Technology Consortium.
• John R. Bradford Endowment at Texas Tech University.
• Paul Whitfield Horn Professorship at Texas Tech University.