Book Review: The Merck Index. An Encyclopedia of Chemicals and Drugs

Monohydrate and anhydrate of nylon 5I monomer 1,5-pentanediamine–isophthalate

“…Related studies on theophylline, ampicillin and naproxen sodium indicate that the water activity (a w ) in the experimental system using mixed solvents is the key factor in determining the mutual transition between hydrate and anhydrate. [24][25][26] For a given temperature, there exists a corresponding equilibrium value of water activity, the relative stability of the anhydrous and hydrated forms is consistent at this time. Besides, any uctuation in the equilibrium water activity under the same conditions may lead to a phase transformation.…”

Discovering crystal forms of the bio-based nylon 5O monomer 1,5-pentanediamine-O-phthalate: insight into the crystal structures, transformations and stability

“…42 A considerable number of studies show that the water activity (a w , corresponding to the relative humidity (RH)) in an experimental system using mixed solvents is the key factor in phase transition between solvates, hydrates, and anhydrates. [43][44][45] It is significant to investigate and figure out the transformation rules among different solid forms. One of the important phase transformation processes is the de-solvation process, which usually results in a new form.…”