Crystallography for Polymorphs

Ochsenbein, Philippe; Schenk, Kurt J.

doi:10.1002/3527607889.ch6

Cited by 9 publications

(7 citation statements)

References 31 publications

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“…The single crystal XRD involves the measurements on a precisely grown single crystal, with the incidence of X-rays on entire crystallographic planes through continuous rotation thus detecting a series of spots resulting from constructive interferences of the diffracted X-rays. The crystallographic interpretations of pharmaceuticals are detailed elsewhere (Ochsenbein and Schenk 2006). Also, the basic theories of X-ray diffraction and scattering are decipherable in several standard text books and are beyond the scope of this chapter.…”

Section: Powder X-ray Diffractometry (Pxrd)mentioning

confidence: 99%

“…The inherent specificity and quantitative power towards the crystalline state make pXRD as the technique of choice for studying crystallization from amorphous systems (Ochsenbein and Schenk 2006). Also, the instrumental flexibility allows in situ monitoring of crystallization as function of time, temperature, pressure, RH, or combinations.…”

Section: Crystallization Studies and Crystallinity Of Amorphous Systementioning

confidence: 99%

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Structural Characterization of Amorphous Solid Dispersions

Paudel

Meeus

Mooter

2014

Advances in Delivery Science and Technology

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Section: Powder X-ray Diffractometry (Pxrd)mentioning

confidence: 99%

Section: Crystallization Studies and Crystallinity Of Amorphous Systementioning

confidence: 99%

Structural Characterization of Amorphous Solid Dispersions

Paudel

Meeus

Mooter

2014

Advances in Delivery Science and Technology

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“…PXRD may be used to study phase transformation related to amorphous and crystalline phases, as it is very specific and quantitative towards the crystalline phase [155]. Moreover, advanced instrumentation permits in situ studies of phase transformation as a function of conditions provided (RH, temperature) to be performed.…”

Section: X-ray Diffraction Techniquesmentioning

confidence: 99%

Pharmaceutical solvates, hydrates and amorphous forms: A special emphasis on cocrystals

Healy

Worku

Kumar

et al. 2017

Advanced Drug Delivery Reviews

284

189

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a b s t r a c t a r t i c l e i n f oActive pharmaceutical ingredients (APIs) may exist in various solid forms, which can lead to differences in the intermolecular interactions, affecting the internal energy and enthalpy, and the degree of disorder, affecting the entropy. Differences in solid forms often lead to differences in thermodynamic parameters and physicochemical properties for example solubility, dissolution rate, stability and mechanical properties of APIs and excipients. Hence, solid forms of APIs play a vital role in drug discovery and development in the context of optimization of bioavailability, filing intellectual property rights and developing suitable manufacturing methods. In this review, the fundamental characteristics and trends observed for pharmaceutical hydrates, solvates and amorphous forms are presented, with special emphasis, due to their relative abundance, on pharmaceutical hydrates with single and two-component (i.e. cocrystal) host molecules.

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“…Similarly, atropisomers are stereoisomers resulting from hindered rotation around single bonds, again with energy high enough to allow isolation of the different forms. Both phenomena are very rare; in 2004, a survey of the Cambridge crystallographic data centre yielded four hits that qualified as atropisomers and ten hits that qualified as rotamers [33]. Despite the rareness of the forms, recent reviews can be found on both rotamers[34,35] and atropisomers [36–38]…”

Section: What's In the Name?mentioning

confidence: 99%

“…Both phenomena are very rare; in 2004, a survey of the Cambridge crystallographic data centre yielded four hits that qualified as atropisomers and ten hits that qualified as rotamers. [33] Despite the rareness of the forms, recent reviews can be found on both rotamers [34,35] and atropisomers. [36][37][38] Solvate (Solvatomorph) is defined as the ability of an API to exist as two or more crystalline phases that have different arrangements or conformations of the molecules in the crystal lattice, where each crystalline phase has a different elemental composition due to the inclusion of one or more molecules of solvent.…”

Section: Introductionmentioning

confidence: 99%

The solid-state continuum: a perspective on the interrelationships between different solid-state forms in drug substance and drug product

Elder

Patterson

Holm

2015

Journal of Pharmacy and Pharmacology

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Objective The objective of the review is to provide an overview of the nomenclature used in the solid-state continuum and relate these to the development of drug substances and drug products. Key findings The importance of a rational approach to solid-state form selection, including integrated decision making (ensuring equal weight is given to the needs of the drug substance and the drug product), is vital for the effective development of a drug candidate. For example, how do secondary processing considerations influence the selection of drug substance solid-state form and resulting formulation, and how can drug substance solid-state form be used to optimise secondary processing? Further, the potential use of 'crystal' engineering to optimise stability, purity and optical resolutions, and the linked regulatory requirements, will be discussed. Summary The nomenclature used in the solid-state continuum, which contains a large number of different crystalline and non-crystalline forms, for example, amorphous systems, was reviewed. Further, the significant role of the drug substance within the solid oral dose form from a physicochemical perspective was covered.

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Crystallography for Polymorphs

Cited by 9 publications

References 31 publications

Structural Characterization of Amorphous Solid Dispersions

Structural Characterization of Amorphous Solid Dispersions

Pharmaceutical solvates, hydrates and amorphous forms: A special emphasis on cocrystals

The solid-state continuum: a perspective on the interrelationships between different solid-state forms in drug substance and drug product

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