Coformer-Dependent Physical Stability in a Series of Naringenin-Based Coamorphous Materials with Caffeine, Theophylline, and Theobromine.

Abstract

To investigate the production and physical stability of coamorphous materials (CAM) of naringenin (NAR) and coformers-caffeine, theophylline or theobromine (CAF/THY/THE, respectively). We independently assessed the impact of moisture and temperature on the physical stability of CAMs, and transformation products after destabilization were examined. Neat grinding, liquid assisted grindingand water slurry were selected to prepare multi-component materials with NAR and CAF, THY or THE. The physical stability of CAMs was investigated at 65°C/<10%RH, 21°C/85% RH and 21°C/<10% RH. Differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) were employed to monitor for recrystallization during the stability studies. Glass forming ability of amorphous NAR was assessed to understand CAM formation and physical stability. NAR:THY and NAR:THE CAMs showed physical stability for approximately nine months, under 21°C/<10% RH while NAR:CAF CAMs destabilized in 2.5weeks. All CAMs recrystallized within a week at 65°C/<10%RH, and the physical stability at 21°C/85% RH was in the order of - NAR:THY > NAR:THE > NAR:CAF. NAR:THY produced 1:1 cocrystal under all storage conditions, while NAR:CAF destabilized to a 1:1 cocrystal at high RH but a physical mixture at high temperature. NAR:THE was found to recrystallize as a physical mixture in all conditions. NAR was found to be strong glass, with moderate kinetic fragility and good glass forming ability. Five naringenin-based multi-component solids were generated in this study: 3 new CAMs, 1 new cocrystal, and 1 previously reported cocrystal. Destabilization of CAMs was found to be exposure specific and coformer dependent.