a. Faculty of Chemistry, University of Latvia, Kr. Valdemara 48, Riga 1013, Latvia

From the experiments where mixture of xylazine hydrochloride hydrate H and anhydrous X were held at constant conditions, the stable form of xylazine hydrochloride can be found out. To determine equilibrium relative humidity, the unstable form of xylazine hydrochloride was inserted in thermostated humidity chamber and its weight was recorded by weighing the sample outside the chamber. The kinetic model and the rate constant for each condition were determined. The rate constants give information regarding the speed of the process at every experimentally used relative humidity. Thus using the data in coordinates k p for each temperature it is possible to determine the water vapor pressure of the equilibrium. With this method the phase boundary for xylazine hydrochloride was determined and hydration enthalpy was calculated. The hydration rates of xylazine polymorphs A and X were investigated.

a. Faculty of Chemistry, University of Latvia, Kr. Valdemara 48, Riga 1013, Latvia

Synthesis of nicotinamide and fumaric acid supramolecular cocrystals with 1 : 1 and 2 : 1 amide to acid stoichiometries results in the formation of an amide-acid heterosynthon (1 : 1 stoichiometry) and an amide-amide homosynthon (2 : 1 stoichiometry) and different conformations of the fumaric acid moieties.