Two methods for the measurement of the dissociation pressure of a crystalline hydrate

Two methods for the measurement of the characteristic dissociation pressures of a system containing water vapor and two different crystalline hydrates of the pharmaceutical compound MK-0677 are described. One method involves the spectroscopic determination of water in gases equilibrated with the solids at controlled temperatures, using an infrared spectrometer. The second method utilized the extrapolated onset temperature of the transition from one hydrate to the other at controlled humidities, as observed by differential scanning calorimetry. The methods give similar results for the system of interest.