Date: Monday, October 16, 2023
Time: 11:30 am - 1:00 pm EST

Plenary Lecture

Prof. Dr. Tomče Runčevski, Southern Methodist University

Title: Thermodynamic and Kinetic Control of Molecular Materials

Abstract: The structure of materials dictates their physicochemical properties. The solidification of organic materials, whether in their crystalline or amorphous state, can occur as a thermodynamically or kinetically driven phenomenon. Here we will discuss modern experimental techniques used to explore the thermodynamically stable forms of organic materials, considering their potential as minerals on Titan, Saturn's moon. Furthermore, we will explore the use of kinetic control to rapidly cool and stabilize new physiologically active materials (drugs, supplements, and pesticides) with tailored properties. Finally, we will delve into post-synthetic modification techniques aimed at disrupting the crystalline integrity of metal-organic frameworks and layered hydroxides. By introducing defects into these materials, we can generate novel properties that are absent in ordered matter.

Time: 11:30 am

Short Talks

Dr. R. Alex Mayo, University of Ottawa
Postdoctoral Researcher - Woo Group

Title: Uncovering value in CSP landscapes with accurate PXRD-based crystal structure comparisons

Abstract: The properties of the solids used in critical applications, from technology to pharmaceuticals, are defined by their structure. Accordingly, changes in this structure, i.e. polymorphism, must be known and controlled. Many crystallographic data from disparate conditions are collected during polymorph screening (150 K single crystal data, PXRD at ambient conditions, static-lattice CSP structures) which must be analyzed to elucidate the polymorphic landscape. The VC-PWDF approach to comparing crystal structures based on PXRD was designed specifically for this purpose. The method resolves peak-shifting due to thermal expansion and is shown to be accurate and robust when comparing SC-XRD structures in the CSD, and SC-XRD structures to CSP structures. Additionally, the use of the simulated PXRD from crystal structures allows for accurate comparisons with experimental PXRD, providing an avenue for structure determination from powder data. The VC-PWDF method and its applications will be discussed in this presentation.

Time: 12:10 pm EST

Amy Neusaenger, University of Wisconsin-Madison
Ph.D. Candidate - Yu Group

Title: Amorphous Drug–Polymer Salts: Maximizing Proton Transfer to Enhance Stability and Release

Abstract: An amorphous drug–polymer salt (ADPS) can be remarkably stable against crystallization at high temperature and humidity (e.g., 40°C/75% RH) and provide fast release. In the case of lumefantrine (LMF), we find that this performance depends strongly on the extent of acid-base reaction between LMF and the acidic polyelectrolyte counterion. For LMF and poly(acrylic acid) (PAA), this extent of reaction follows a single trend independent of PAA MW in which the degree of drug protonation increases with PAA concentration, describing the equilibrium for salt formation. This analysis has been extended to other common pharmaceutical acidic polymers, where we show that the ability of these polymers to protonate LMF follows the order of the acidic group density assessed via non-aqueous titration performed in the same solvent used for slurry synthesis. These results are relevant for selecting the optimal ASD polymer and controlling the degree of ionization in amorphous drug-polymer salts.

Time: 12:35 pm