Drug-drug cocrystals of theophylline with quercetin

Drug-drug cocrystals have received growing attention in pharmaceutical industry for the ability to present a strategy for the development of fixed-dose combination drugs. In this study, two novel drug-drug cocrystals (one hydrate and one anhydrate) composed of theophylline (THP) and quercetin (QUE) were obtained. The hydrate, THP-QUE-H, was prepared by liquid-assisted grinding method, and the anhydrate, THP-QUE-A, was harvested by heat-treatment of the THP-QUE-H at about 235 degrees C. Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis showed that the THP-QUE-H transformed to the THP-QUE-A at about 235 degrees C and the melting point was 247 degrees C, indicating both the cocrystals were thermally stable at environment temperature. Additionally, both cocrystals maintained a stable state after 30-day under 25 degrees C/90% RH condition or after 30-day under 25 degrees C/15% RH condition. Such results indicate the two THP-QUE cocrystals might show potential as suitable solid forms for the further development as pharmaceutical products.

Automated summary

In this study, two drug-drug cocrystals composed of theophylline and quercetin were obtained and shown to be thermally stable at environment temperature and maintained stability under different humidity conditions. These cocrystals may serve as suitable solid forms for further pharmaceutical product development.