Effect of position isomerism on the formation and physicochemical properties of pharmaceutical co-crystals.

The effect of position isomerism on the co-crystals formation and physicochemical properties was evaluated. Piracetam was used as the model compound. Six position isomers, 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, and 3,5-dihydroxybenzoic acid (DHBA), were used as the co-crystal formers.

Dehydration behavior and structural characterization of the GW275919X monohydrate.

GW275919X, a central muscle relaxant for the treatment of lower back pain, exists in a monohydrate. Knowledge of the solid state dehydration behavior and the crystal structure is essential for determining its relative physical stability. Thermal analysis and hot-stage powder X-ray diffraction were used to study the solid state phase transformation during the dehydration process.

Solubilization and solid-state characterization of a poorly soluble 5-alpha reductase inhibitor.

GI197111X is a 5-alpha reductase inhibitor for the treatment of androgenetic alopecia. Equilibrium solubilities of GI197111X were determined in multiple solvents or cosolvents. A polymorph screen was conducted using suspension equilibration and solution recrystallization methods.

Solid state characterization of an neuromuscular blocking agent--GW280430A.

GW280430A is an ultrashort-acting neuromuscular blocking agent and is targeted for muscle relaxation as part of the intubation surgical procedure. The objective of this work was to perform solid state characterization on GW280430A and to evaluate the relationship between water content and glass transition temperature (Tg). GW280430A was characterized by differential scanning calorimetry, thermogravimetric analysis, powder X-ray diffraction (PXRD), microscopy and moisture sorption.

Crystal structure and thermal behavior of nedocromil nickel octahydrate.

The hydration behavior of a salt depends on the nature of the cation and the anion and on the molecular packing. A transition metal salt (nickel) of nedocromil was prepared and its crystal structure was elucidated in an attempt to study the influence of the nature of the bivalent cation on the structure, water interactions and molecular packing. Crystal data: nedocromil nickel octahydrate (NNi), orthorhombic, Pca2(1), a=29.