Formation and Transformation Behavior of Sodium Dehydroacetate Hydrates

Abstract

Abstract:The effect of various controlling factors on the polymorphic outcome of sodium dehydroacetate crystallization was investigated in this study. Cooling crystallization experiments of sodium dehydroacetate in water were conducted at different concentrations. The results revealed that the rate of supersaturation generation played a key role in the formation of the hydrates. At a high supersaturation generation rate, a new sodium dehydroacetate dihydrate needle form was obtained; on the contrary, a sodium dehydroacetate plate monohydrate was formed at a low supersaturation generation rate. Furthermore, the characterization and transformation behavior of these two hydrated forms were investigated with the combined use of microscopy, powder X-ray diffraction (PXRD), Raman spectroscopy, Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM) and dynamic vapor sorption (DVS). It was found that the new needle crystals were dihydrated and hollow, and they eventually transformed into sodium dehydroacetate monohydrate. In addition, the mechanism of formation of sodium dehydroacetate hydrates was discussed, and a process growth model of hollow crystals in cooling crystallization was proposed.

Influence of Solution Composition and Temperature on the Crystal Form of Sodium Dehydroacetate

“…The driving force of DHA‐S MH II crystallization from a solution is supersaturation. As reported earlier , , the rate and method of supersaturation generation may influence the polymorphic state and morphology of the crystals. The crystallization of DHA‐S MH II from methanol and water is not a conventional evaporative crystallization process.…”

“…). It was reported to have anhydrate, commercial monohydrate (from here on referred to as MH I), and hollow crystals of dihydrate . In our earlier report , high‐quality DHA‐S anhydrate was obtained by transforming MH I to anhydrate in pure methanol solvent.…”

Controlled Recrystallization of Tubular Vinpocetine Crystals with Increased Aqueous Dissolution Rate and In Vivo Bioavailability

“…Shape-controlled crystallization has been a hot topic of investigation in recent years. , However, the mechanism involved in the crystal shape formation and evolution is always complex. Meanwhile, crystal transition and polymorphism tend to occur during this multiparameter controlled process, , which makes it more challenging to get a profound understanding of the related growth mechanism. In this paper, a series of VIN crystals with different shapes have been prepared via the antisolvent method (Figure ).…”