Effect of crystal growth kinetics on the formation of liquid inclusions in tetramethylpyrazine crystals

Abstract

Inclusion of mother liquids inside the pharmaceutical crystals poses a great challenge and threat to the product quality and purification efficiency. Herein we demonstrate how growth kinetics tune the formation of liquid inclusion and its occluded mechanism.

Molecular crystalline capsules that release their contents by light

“…1e, ESI Movie 2 †). The hollows were formed parallel to the fast-growing axis similarly to the recent reports of inclusions in organic molecular crystals, 16,18 and the formation mechanism of the crystalline capsules was in accordance with these references where the formation mechanism is attributed to the inhomogeneous growth of crystals. In this work as well, the appearance of cavities due to inhomogeneous growth of the crystals, and trapping of the solution in the cavities were observed.…”

“…The capsule is sealed and can take in any solute in the solvent in principle. Such organic molecular crystals with sealed hollows have been known since the turn of the century, 15,16 but only recently have attempts been made to deliberately create and control them. 17,18 The capsule released its contents in 1 second by UV irradiation.…”

A Structured Approach To Cope with Impurities during Industrial Crystallization Development

“…A more steady increase in impurity concentration c i which reaches full impurity dissolution during the middle stages of the bulk crystal dissolution would indicate significant growth-induced or attrition-induced inclusions (Figure , inclusions). The presence of inclusions can be investigated further using imaging techniques such as high resolution microscopy. ,, The distribution of macroscopic solvent inclusions in a crystal is determined by its growth and collision history, which in turn are strongly related to the process conditions during crystallization. While it may be difficult to pinpoint to a responsible inclusion formation mechanism from the impurity mapping experiments, the dissolution trends allow the user to prioritize subsequent experimental approaches to do so.…”

Impact of a Partial Solid Solution and Water Molecules on the Formation of Fibrous Crystals and Fluid Inclusions

“…Nevertheless, in the present case, there are roughly two symmetrical vacuoles located at both ends of the particle; they are filled with the saturated mother liquor and a bubble of gas. This is in contrast with other cases for which fluid inclusions are repeated along a given crystallographic axis [6,14].…”