Solid-state emulsions: the effects of process and storage conditions

The effects of process and storage conditions of solid-state emulsions were studied. Oil-in-water emulsions may be prepared from solid state emulsions by adding an aqueous phase to the solid. Solid-state emulsions are prepared by processing an oil phase and an aqueous solution of matrix material via a solvent removal process. Sucrose, the carrier material utilized in this report, results in a metastable solid or glass, which can transform upon aging to a more stable thermodynamic state. Aging was determined by monitoring the crystallinity as a function of time, temperature, relative humidity, and grinding. The crystallinity of solid-state emulsions was determined with X-ray diffraction and differential scanning calorimetry. Results indicate that solid-state emulsions should be stored between 15 and 25% relative humidity at 25 degrees C. Grinding has no apparent effect on the crystallinity of the sample, as detected by X-ray diffraction, although the microcrystallinity is increased. The utilization of silinized glassware enabled the sample-to-sample microcrystalline variability to be reduced.