Abstract
The physicochemical properties of drug molecules in a mixture with controlled-pore glass (CPG) were studied by using differential scanning calorimetry (DSC) and powder X-ray diffraction. The DSC data indicated the presence of three states of benzoic acid in the CPG mixtures below 500 A^^° CPG pore diamter. The proportions of the three states of benzoic acid in the CPG mixture varied with the content of benzoic acid and also with the pore diamter of CPG. The amount of crystalline fraction in the mixture increased with increasing pore diameter of CPG. When benzoic acid was mixed with different pore diameters of CPG (CPG120 and CPG1000), it was found that benzoic aicd molecules preferentially interacted with CPG of small pore diameter.
