Process-induced phase transformation of carbamazepine dihydrate to its polymorphic anhydrates

Khoo, Ji Yi; Shah, Umang V.; Schaepertoens, Marc; Heng, Jerry Y. Y.

doi:10.1016/j.powtec.2012.04.059

Cited by 25 publications

(26 citation statements)

References 46 publications

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“…For instance, it is well reported that crystals of mefenamic acid form I, crystallized from a supersaturated toluene solution ( 20 ) are needle shaped, similar to crystals of mefenamic acid form II ( 21 ). Similarly carbamazepine polymorphs II, III and IV have been isolated as needle shaped crystals as well ( 22 ). The occurrence of crystals of the same molecule, but of different polymorphic form, with the same crystal habit poses limitations for the identification of the different polymorphs by means of optical microscopy.…”

Section: Concepts In Crystal Growth and Dissolutionmentioning

confidence: 99%

Influences of Crystal Anisotropy in Pharmaceutical Process Development

et al. 2018

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Crystalline materials are of crucial importance to the pharmaceutical industry, as a large number of APIs are formulated in crystalline form, occasionally in the presence of crystalline excipients. Owing to their multifaceted character, crystals were found to have strongly anisotropic properties. In fact, anisotropic properties were found to be quite important for a number of processes including milling, granulation and tableting. An understanding of crystal anisotropy and an ability to control and predict crystal anisotropy are mostly subjects of interest for researchers. A number of studies dealing with the aforementioned phenomena are grounded on over-simplistic assumptions, neglecting key attributes of crystalline materials, most importantly the anisotropic nature of a number of their properties. Moreover, concepts such as the influence of interfacial phenomena in the behaviour of crystalline materials during their growth and in vivo, are still poorly understood. The review aims to address concepts from a molecular perspective, focusing on crystal growth and dissolution. It begins with a brief outline of fundamental concepts of intermolecular and interfacial phenomena. The second part discusses their relevance to the field of pharmaceutical crystal growth and dissolution. Particular emphasis is given to works dealing with mechanistic understandings of the influence of solvents and additives on crystal habit. Furthermore, comments and perspectives, highlighting future directions for the implementation of fundamental concepts of interfacial phenomena in the rational understanding of crystal growth and dissolution processes, have been provided.

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Section: Concepts In Crystal Growth and Dissolutionmentioning

confidence: 99%

Influences of Crystal Anisotropy in Pharmaceutical Process Development

et al. 2018

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“…Finally, powder XRD (Figure c) characterization on the CBZ7–Alg5 sample shows that CBZ was mainly Form I (triclinic form), which came from the dehydration of the original CBZ dihydrate crystals obtained with water as an antisolvent. The dehydration process has been well studied by Khoo et al, who showed that a water‐mediated low‐rate dehydration yields Form I CBZ. Freeze drying behaves similarly; with the slow sublimation of water, the crystals obtained in this case were also of Form I.…”

Section: Resultsmentioning

confidence: 99%

Droplet‐Templated Antisolvent Spherical Crystallization of Hydrophilic and Hydrophobic Drugs with an in situ Formed Binder

Yeap

Cao

et al. 2017

Adv Healthcare Materials

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This study presents a novel droplet-templated antisolvent spherical crystallization method applicable to both hydrophilic and hydrophobic drugs. In both cases, an alginate hydrogel binder forms in situ, concurrently with the crystallization process, effectively binding the drug crystals into monodisperse spheres. This study presents a detailed process description with mass transfer modeling, and with characterization of the obtained alginate/drug spheres in terms of morphology, composition, and drug loading. Although glycine and carbamazepine are used as model hydrophilic and hydrophobic drugs, this method is easily generalized to other drugs, and offers several benefits such as minimal thermal impact, fast crystallization rates, high drug-binder loading ratios, and high selectivity toward metastable polymorphs.

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“…In addition, small amounts of amorphous phase can markedly increased the water uptake. Complex phase transitions dependent on temperature and humidity are common . These properties mean that processing steps during secondary manufacture such as drying, micronization, granulation, compression, and coating have to be carefully controlled to ensure that unwanted forms are not generated .…”

Section: Introductionmentioning

confidence: 99%

“…Complex phase transitions dependent on temperature and humidity are common. 6 These properties mean that processing steps during secondary manufacture such as drying, micronization, granulation, compression, and coating have to be carefully controlled to ensure that unwanted forms are not generated. 7 Some secondary processing steps such as wet granulation are the ideal setting for the creation of hydrates as they introduce excess water to the system, often followed by mixing, which leads to intimate association between the Active Pharmaceutical Ingredient (API) and water.…”

Section: Introductionmentioning

confidence: 99%