METHOD FOR EVALUATING THE SOLUBILITY OF A CRYSTALLINE SUBSTANCE IN A POLYMER

摘要

A viable strategy to enhance the bioavailability of poorly soluble drugs is to use amorphous solids in place of the more commonly used crystalline solids in pharmaceutical formulations. However, amorphous solids are physically meta-stable and tend to revert back to their crystalline counterpart. An effective approach to stabilizing an amorphous drug against crystallization is to disperse it in a polymer matrix. The drug's solubility in the chosen polymer defines the upper limit of drug loading without any risk of crystallization. Measuring the solubility of a drug in a polymer has been a scientific and technological challenge because the high viscosity of polymers makes achieving solubility equilibrium difficult and because pharmaceutically important drug/polymer dispersions are glasses, which undergo structural relaxation over time. The invention provides a method based on Differential Scanning calorimetry (DSC) for measuring the solubility of crystalline drugs in polymeric matrices. The method relies on the detection of the dissolution endpoint of a drug/polymer mixture prepared by cryomilling.