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Glucosamine hydrochloride (GAH) is a kind of natural hexose, which is used to promote the synthesis of mucopolysaccharides and improve the metabolism of articular cartilage. In this paper, the solubility of GAH in pure water and aqueous system with the presence of three kinds of additives (HCl, NaCl, KCl) at temperatures ranging from 278.15 K to 323.15 K was determined by gravimetric method. When there are additives in water, the solubility of GAH increases with the increase of temperature and decreases with the increase of concentration of the three kinds of additives. When the additives were at similar mole fractions, HCl led to the lowest solubility of GAH. The modified Apelblat model and van't Hoff model were used to correlate the solubility data. The average relative deviation (ARD) data of Apelblat and van't Hoff models were less than 5%, indicating good fitting results. Based on the thermodynamic data, the cooling crystallization process of GAH was performed. It was found that the additives could affect the crystal morphology, particle size, and yield of GAH products. This study supplemented the thermodynamic data of GAH and studied the cooling crystallization process in the presence of GAH additives, which provided important guidance for the optimization of the crystallization process. [ABSTRACT FROM AUTHOR]

The crystal morphology of glucosamine hydrochloride (GAH) during antisolvent crystallization was investigated in this work. Particles of different shapes, such as plate-like crystals, leaflike clusters, fan-like dendrites, flower-like aggregates, and spherulites, were produced by tuning the type of antisolvents and crystallization operating conditions. The hierarchical structures of GAH crystals tended to be formed in a water + isopropanol mixture. The effects of operation parameters on the polycrystalline morphology were studied, including crystallization temperature, solute concentration, feeding rate of GAH aqueous solution, solvent-to-antisolvent mass ratio, and stirring rate. The evolution process of GAH spherulites was monitored using SEM, indicating a crystallographic branching mode. The crystal habit was predicted to identify the dominant faces. Molecular dynamics simulations were performed and the interaction energy of solute or solvent molecules on crystal surfaces was calculated. The experimental and simulation studies help to understand the branching mechanism and design a desired particle morphology. [ABSTRACT FROM AUTHOR]

The latest developments of industrial crystallization in China are reviewed. This includes the introduction of representative scientists and institutions promoting the progress of Chinese industrial crystallization. Additionally, primary application fields related to industrial crystallization are outlined to give an overview of the current research trends in China. National and international industrial crystallization meetings held in China are also presented. Finally, the expectations for the future research activities in the field of industrial crystallization in China are briefly described. [ABSTRACT FROM AUTHOR]

Thiamine hydrochloride (THCL) was produced in methanol accompanied with agglomeration in industry, the plate like morphology of THCL in methanol was not deserve to have a good quality. Selecting a suitable solvent should be considered because solvent could be one of the essential factors to impact morphology. Methanol and methanol/ethyl acetate solvent (0.2 vol fraction of methanol) was selected as the solvent system in reactive crystallization of THCL. The experiment results show the THCL crystal morphology in methanol/ethyl acetate solvent system was granular and more regular than that in methanol. In order to explicate the different crystal morphology in different solvents, molecular dynamics (MD) simulation was introduced to simulate crystal morphology in different solvents. The attachment energy (AE) model was employed to investigate the morphology of THCL under vacuum conditions, methanol and methanol/ethyl acetate solvent conditions, respectively. The simulation crystal morphology was in a good agreement with that of experimented. The particle of THCL in methanol/ethyl acetate solvent has less tendency to agglomeration, and then it is favorable to the downstream process, such as filtration, storage and transportation. [ABSTRACT FROM AUTHOR]

• Influence of the solvent on the crystal habit of nifedipine was investigated. • Indexing of the crystal facets was performed. • The crystal packing and intermolecular interactions were examined. • Hydrogen bonding interactions turn the crystal morphology of nifedipine. The modification of the crystal habits by the solvent selection approach has been widely applied. However, the underlying regulation mechanism by solvents, specifically solute recognition and assembly process at crystal-solution interface is not yet well-understood. Herein, the effects of solvents on crystal habit and interface assembly of nifedipine (NFD) were investigated by growth experiments in five selected organic solvents of distinct hydrogen bond affinity properties. It was found that the crystal habits of NFD can be tuned by the hydrogen bond acceptor (HBA) ability of solvents, which elevates the aspect ratio of the crystals. The X-ray diffraction (XRD) and differential scanning calorimeter (DSC) further confirmed that no polymorphs were involved and related with the morphology changes. The face indexing calculated by single crystal XRD of experimental morphologies, Hirshfeld surface analysis, and the surface chemistry of the different crystal facets revealed a directionality of solvent interactions with crystal faces, induced by the solute-solvent hydrogen bonding interactions. Further, the strength of the solute-solvent interactions quantified by the adsorption energy calculations and the RDF analyses correlates well with the HBA ability of the solvents and the experimental morphology. In all, it was unveiled that the directionality of solute-solvent hydrogen bonding interactions interrupts anisotropically the recognition and assembly of solutes at the crystal-solution interface, resulting in the modification of the crystal morphology. [ABSTRACT FROM AUTHOR]

Effects of polymeric additive and ultrasound on the morphology of ropivacaine crystals. [Display omitted] • The needle-like ropivacaine was modified as block-like crystals by adding little PVP in the crystallization system. • In ultrasound-assisted crystallization, the particles of ropivacaine precipitated at extended ultrasonic time exhibited plate-like crystals with shorter aspect ratio. • Combined using of polymeric additive and ultrasound led to rice-shaped crystals, which the average particle size was further decreased. • The mechanism for the morphological evolution of ropivacaine crystals assisted by PVP and ultrasound was proposed based on the experiments and molecular dynamics simulation. The objective of this research was to modify the crystal shape and size of poorly water-soluble drug ropivacaine, and to reveal the effects of polymeric additive and ultrasound on crystal nucleation and growth. Ropivacaine often grow as needle-like crystals extended along the a -axis and the shape was hardly controllable by altering solvent types and operating conditions for the crystallization process. We found that ropivacaine crystallized as block-like crystals when polyvinylpyrrolidone (PVP) was used. The control over crystal morphology by the additive was related to crystallization temperature, solute concentration, additive concentration, and molecular weight. SEM and AFM analyses were performed providing insights into crystal growth pattern and cavities on the surface induced by the polymeric additive. In ultrasound-assisted crystallization, the impacts of ultrasonic time, ultrasonic power, and additive concentration were investigated. The particles precipitated at extended ultrasonic time exhibited plate-like crystals with shorter aspect ratio. Combined use of polymeric additive and ultrasound led to rice-shaped crystals, which the average particle size was further decreased. The induction time measurement and single crystal growth experiments were carried out. The results suggested that PVP worked as strong nucleation and growth inhibitor. Molecular dynamics simulation was performed to explore the action mechanism of the polymer. The interaction energies between PVP and crystal faces were calculated, and mobility of the additive with different chain length in crystal-solution system was evaluated by mean square displacement. Based on the study, a possible mechanism for the morphological evolution of ropivacaine crystals assisted by PVP and ultrasound was proposed. [ABSTRACT FROM AUTHOR]

Potassium chloride crystals are cubic, which often leads to caking and greatly limits their applications. This caking can be overcome by modifying the crystal shape toward sphericity. Spherical particles have a high anti-caking ability and flowability. In this work, spherical KCl particles were prepared using a simple cooling crystallization process designed to function without additives. Among the four main processes in the crystallization of spherical particles, i.e., nucleation, growth, agglomeration, and attrition, agglomeration is the greatest contributor to the formation of spherical KCl particles, which were prepared following the principle that the adhesion force must be larger than the dispersion force. The adhesion free energy between KCl particles and solvents (i.e., water, n -hexane, formamide, diazomethane, methanol, ethanol, ethyl acetate, ethylene glycol, and dimethyl sulfoxide) was calculated using the Lifshitz–van der Waals acid–base approach, and water was found to be the most appropriate solvent because of its attractive interaction with the crystals. According to the relationship between the adhesion force and dispersion forces, we found that the stirring rate should be lower than 1300 rpm. Additionally, the effects of stirring rate and cooling rate on the KCl products were investigated and optimized, and the optimal conditions were found to be 400–500 rpm and 10–15 min/ ° C, respectively. All of the spherical KCl products prepared under the optimal conditions show a better morphology, flowability, and anti-caking performance than the original crystals. [ABSTRACT FROM AUTHOR]

• Cellulose polymers modify the crystal habit of DL-methionine in aqueous solution. • 2D growth rates of DL-methionine were both inhibited by polymeric additives. • Hirshfeld surface analysis, MEPs and MD simulations were performed. • Surface adsorption and steric hindrance of polymers are key for growth inhibition. Cellulose derivatives such as hydroxyethyl cellulose (HEC), methylcellulose (MC) and hydroxypropyl methycellulose (HPMC) were employed to modify the morphology and growth of DL-methionine crystals. The methodology involved a systematic study through batch cooling crystallization, slow solvent evaporation, seeded single crystal growth, solid-state characterization, and molecular simulation. The presence of the polymeric additive, at very low concentrations (1–100 ppm), has modified the crystal shape from elongated leaf-like crystals to hexagonal plates or blocks with smaller aspect ratio. All three polymers exhibited strong retardation on crystal growth along the b -axis (length) and c -axis (width) direction. The growth inhibition degree depends on the types and concentrations of the additives, which can be ranked as HPMC > MC > HEC at same concentration. To further explore the mechanism of polymeric additives on morphology modulation and growth inhibition, Hirshfeld surface analysis, molecular electrostatic potential surface calculations, and molecular dynamic simulations of additive-crystal surface system as well as aqueous solution-crystal surface system were carried out. The molecular modeling revealed surface adsorption of additives on crystal faces via electrostatic interactions, van der Waals interactions, and hydrogen bonds. Other factors like hydrophobic interactions and steric hindrance effect of polymers also have significant impact on crystal growth inhibition. [ABSTRACT FROM AUTHOR]