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PURPOSE To measure the molecular mobility of amorphous pharmaceutical solids below their glass transition temperatures (Tg), using indomethacin, poly (vinyl pyrrolidone) (PVP) and sucrose as model compounds. METHODS Differential scanning calorimetry (DSC) was used to measure enthalpic relaxation of the amorphous samples after storage at temperatures 16-47(More)
The amorphous state is critical in determining the solid-state physical and chemical properties of many pharmaceutical dosage forms. This review describes the characteristics of the amorphous state and some of the most common methods that can be used to measure them. Examples of pharmaceutical situations where the presence of the amorphous state plays an(More)
PURPOSE To evaluate the magnitude of the solubility advantage for amorphous pharmaceutical materials when compared to their crystalline counterparts. METHODS The thermal properties of several drugs in their amorphous and crystalline states were determined using differential scanning calorimetry. From these properties the solubility advantage for the(More)
The solid state crystallization of amorphous polymers, sugars, and inorganic glasses is often thought to be restricted to the region above the glass transition temperature, Tg, because insufficient molecular mobility (high viscosity) exists below Tg for nucleation and crystal growth. Here we report on the isothermal and nonisothermal crystallization of dry(More)
Differential scanning calorimetry and powder X-ray diffraction studies have been carried out with amorphous coprecipitates of indomethacin and poly(vinylpyrrolidone), PVP, to measure the glass transition temperature, Tg, as a function of mixture composition and the nonisothermal and isothermal crystallization of the indomethacin. Values of Tg as a function(More)
The glass transition temperature of an amorphous pharmaceutical solid is a critical physical property which can dramatically influence its chemical stability, physical stability, and viscoelastic properties. Water frequently acts as a potent plasticizer for such materials, and since many amorphous solids spontaneously absorb water from their surroundings(More)
PURPOSE To test the hypothesis that the molecular motions associated with chemical degradation in glassy amorphous systems are governed by the molecular motions associated with structural relaxation. The extent to which a chemical process is linked to the motions associated with structural relaxation will depend on the nature of the chemical process and(More)
The physical, flow, and mechanical properties of four common pharmaceutical sweeteners were measured to assess their relative manufacturability in solid dosage formulations. Sucrose, acesulfame potassium (Sunett), saccharin sodium, and aspartame were evaluated to determine significant differences in particle shape, size distribution, and true density.(More)
PURPOSE Evaluation of the effect of formulation composition and processing variables on the microenvironment in solid dosage forms, based on ionization of indicator probes. MATERIALS AND METHODS Sulfonephthalein indicators were intimately mixed with individual excipients, binary excipient mixtures or multi-component blends by the solvent deposition(More)