Highly stable glasses of celecoxib: Influence on thermo-kinetic properties, microstructure and response towards crystal growth

Celecoxib, an anti-inflammatory drug widely used as a pharmaceutical product, is known for its poor ability to form a glass and its high tendency towards crystallization. Here, we report the preparation of vapor-deposited ultrastable glasses of Celecoxib with an onset temperature of the glass transition 20 K above its conventional value and a high thermodynamic stability. The time required for the loss of molecular anisotropy is 3 orders of magnitude higher than the time scales required for the alpha relaxation. We also report the influence of the stability of the glass on the surface crystallization at temperatures below the glass transition temperature. The growth of surface crystals is 30% faster in conventional glasses prepared from the liquid than in highly stable glasses.