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Meyer, Marvin C.; Straughn, Arthur B.; Jarvi, Eric J.; Wood, George C.; Pelsor, Francis R.; Shah, Vinod P.

doi:10.1023/a:1015872626887

Cited by 140 publications

(35 citation statements)

References 5 publications

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“…Differences due to polymorphism and pseudopolymorphism in pharmaceuticals are of importance, as physicochemical properties (e.g. solubility) can affect bioavailability and effective clinical use [1,2]. Carbamazepine has at least four polymorphic forms and a dihydrate [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Dissolution and mechanical behaviors of recrystallized carbamazepine from alcohol solution in the presence of additives

Nokhodchi

Bolourtchian

Dinarvand

2005

Journal of Crystal Growth

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Section: Introductionmentioning

confidence: 99%

Dissolution and mechanical behaviors of recrystallized carbamazepine from alcohol solution in the presence of additives

Nokhodchi

Bolourtchian

Dinarvand

2005

Journal of Crystal Growth

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“…22 -24 The polymorphs and hydrates of carbamazepine have been shown to exhibit different dissolution rates and bioavailabilities and different commercial brands of carbamazepine tablets have a history of bioinequivalence and clinical failure, which may be due to polymorphism. 25,26 Therefore, carbamazepine is one example that illustrates the necessity to identify and quantify pharmaceutical polymorphs as fully as possible.…”

Section: Introductionmentioning

confidence: 99%

Quantitative analysis of polymorphic mixtures of carbamazepine by Raman spectroscopy and principal components analysis

Strachan

Pratiwi

Gordon

et al. 2004

J Raman Spectroscopy

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The polymorphic behaviour of drugs is a major concern of the pharmaceutical industry as it may have considerable formulation, therapeutic, legal and commercial implications. It is therefore crucial to be able adequately to identify and quantify different polymorphic forms of drugs as early as possible in the drug discovery and development process. The aim of the present study was to investigate the application of Raman spectroscopy and principal components analysis (PCA) to the quantitative analysis of polymorphic mixtures of carbamazepine forms III and I, based on both individual peak areas and heights in the Raman spectra and whole wavenumber ranges. Various linear regressions indicated that in general using every fourth wavenumber value of a larger region of the Raman spectrum gives better quantitative results than choosing defined peak areas and peak heights, as the spectral differences between the polymorphs were only subtle. Baseline correction of the spectral data did not appear to improve the quantitative analysis, with detection and quantification limits being the lowest (0.33 and 1.09%, respectively) and R 2 being the highest (0.96) when using every fourth wavenumber value from 2950 to 3100 cm −1 as input data for the PCA analysis without baseline correction. This study demonstrated that PCA of Raman spectroscopic data provides a sensitive method for the quantitative analysis of polymorphic forms, with a quantitation limit of <2%, if the spectral input data are selected carefully. In the absence of clear and distinct spectral differences at certain wavenumbers between the polymorphic forms, selection of larger spectral regions that contain most of the detectable differences between the two forms appears to be the best data selection technique.

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“…23 Therefore, carbamazepine is one example that illustrates the necessity to identify, monitor and understand pharmaceutical polymorphs as fully as possible.…”

Section: Introductionmentioning

confidence: 99%

A theoretical and spectroscopic study of carbamazepine polymorphs

Strachan

Howell

Rades

et al. 2004

J Raman Spectroscopy

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The drug carbamazepine has been modeled, using ab initio density functional theory calculations [B3LYP/6-31G(d)], both as a single molecule and as a dimer. The predicted geometry of the single molecule calculation is compared with the crystallographic data on each of the polymorphs (carbamazepine forms I and III). From the predicted geometry it is possible to calculate the IR and Raman spectra; these predictions compare favorably with the observed spectra of both polymorphs of carbamazepine for most of the bands. The spectral differences between the polymorphs are more striking in the IR than the Raman spectra, with strong IR bands at 1688 and 1396 cm −1 in form I shifting to 1678 and 1388 cm −1 in form III. Analysis of the potential energy distributions for the calculated normal modes reveals that the vibrations are localized across different ring systems of the carbamazepine structure. Most notably, the polymorph-sensitive modes in the IR spectra are localized to the pendant CONH 2 group; it is these modes that show the greatest disparity from the calculated spectra, and it is this group that is perturbed in the polymorph crystal structures. The calculated dimer structure is similar to that of the single molecule, but the polymorph-sensitive IR modes are significantly better predicted by the dimer calculation.

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Cited by 140 publications

References 5 publications

Dissolution and mechanical behaviors of recrystallized carbamazepine from alcohol solution in the presence of additives

Dissolution and mechanical behaviors of recrystallized carbamazepine from alcohol solution in the presence of additives

Quantitative analysis of polymorphic mixtures of carbamazepine by Raman spectroscopy and principal components analysis

A theoretical and spectroscopic study of carbamazepine polymorphs

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