Quantifying low levels of polymorphic impurity in clopidogrel bisulphate by vibrational spectroscopy and chemometrics

Német, Zoltán; Demeter, Ádám; Pokol, György

doi:10.1016/j.jpba.2008.09.042

Cited by 20 publications

(18 citation statements)

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“…45 Analytical methods based on IR absorption and Raman spectroscopies (combined with chemometrics) were developed to quantify levels of clopidogrel bisulfate Form-II in mixtures with Form-I. 46 Limits of quantitation of 2% (IR method) and 3% (Raman method) were reported with limits of detection being less than 1%. Four crystal forms of emodepside were characterized with the aim of learning whether Forms-II through IV were authentic hydrates or whether they were modifications in which water was substantially absorbed.…”

Section: Structural Characterization and Properties Of Polymorphs Andmentioning

confidence: 99%

Polymorphism and Solvatomorphism 2009

Brittain¹

2011

Journal of Pharmaceutical Sciences

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Section: Structural Characterization and Properties Of Polymorphs Andmentioning

confidence: 99%

Polymorphism and Solvatomorphism 2009

Brittain¹

2011

Journal of Pharmaceutical Sciences

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“…Since, it is difficult to quantify the unwanted form with low limit of detection by X-ray powder diffractometry. Raman spectrometry is not very sensitive to the physical apparition of the sample, which means that many solid samples can be studied directly without sample preparation, but it is sensitive to conditions at the molecular level [12][13][14]. Quantification is based on the direct proportionality of the intensity of the specific band of the component and its concentration in the mixture.…”

Section: Introductionmentioning

confidence: 99%

FT-Raman Spectroscopy with Chemometric Methods for Quantification of Lamivudine Form II in Lamivudine Form I

Rao¹,

Reddy²,

Sekhar³

et al. 2017

Asian J. Chem.

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Lamivudine is known to exhibit polymorphism and the needle-shaped crystals are named as Form I and the bipyramidal crystals as Form II. The FT-Raman spectrum of lamivudine Form II and I shows characteristic bands at 798, 463 cm -1 and 697 cm -1 Raman shifts, respectively. FT-Raman spectroscopy method combined with chemometrics was developed for quantitative analysis of lamivudine Form II in lamivudine Form I drug substance. Solid mixtures of Form I and Form II shows the relative intensity of the characteristic bands at 798, 463 and 697 cm -1 were proportional to the relative amounts of Form I and Form II in mixtures. A calibration was made which is linear in the range from 1.0 to 20.0 % (w/w) of Form II in Form I. The results indicate that levels down to 3.0 % (w/w) of Form II could be quantified using this non-destructive approach, with less than 1.5 % (w/w) limit of detection.

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“…Although examples are still relatively few and scattered, chemometric methods are gaining acceptance as means for studying drug polymorphism [42,43] and we have used the chemometrics analysis of drug dissolution data as a tool to assign the polymorphic identity of furosemide forms in capsules [44]. In this association, infrared spectroscopy provides molecular information, whereas chemometric analysis enables extraction of relevant from the spectral data.…”

Section: Introductionmentioning

confidence: 99%