Polymorphic behaviour of chloroquine diphosphate

Aerde, Ph. Van; Remon, Jean‐Paul; Rudder, D. De; Severen, R. Van; Braeckman, P

doi:10.1111/j.2042-7158.1984.tb06937.x

Cited by 10 publications

(2 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The common thermal methods used for characterization of polymorphs, solvates, and hydrates are differential scanning calorimetry (DSC), , differential thermal analysis (DTA), − and thermogravimentric analysis (TGA), which reveal phase transitions in solids. Optical, − hot-stage, and electron microscopy are used for morphological analysis.…”

Section: Introductionmentioning

confidence: 99%

Necessity of Establishing Chemical Integrity of Polymorphs of Drug Substance Using a Combination of NMR, HPLC, Elemental Analysis, and Solid-State Characterization Techniques: Case Studies

Sawant

Naik

2013

Org. Process Res. Dev.

View full text Add to dashboard Cite

Polymorphism is a solid-state phenomenon; hence, solid-state techniques such as XRPD, DSC, and FT-IR are used for characterization. Many a time, only XRPD is used. These techniques ignore the most important aspects, i.e., chemical purity and the chemical integrity of the polymorph, which can be confirmed by techniques such as 1 H NMR, HPLC, and elemental analysis. The aim of this article is to emphasize how techniques such as 1 H NMR, elemental analysis, and HPLC purity in addition to other solid-state characterization techniques would help to prove that the drug really exists in different polymorphic forms. H 1 NMR, HPLC, and elemental analysis reveal the formation of different compounds and not polymorphs in the case of pioglitazone•HCl and glyburide. In the cases of irbesartan and ropinirole•HCl use of a single solid-state characterization technique such as XRPD is not enough for establishing the existence of different polymorphic forms.

show abstract

Section: Introductionmentioning

confidence: 99%

Necessity of Establishing Chemical Integrity of Polymorphs of Drug Substance Using a Combination of NMR, HPLC, Elemental Analysis, and Solid-State Characterization Techniques: Case Studies

Sawant

Naik

2013

Org. Process Res. Dev.

View full text Add to dashboard Cite

show abstract

“…Most of these techniques are based on crystallography, microscopy, thermal analysis, vibrational spectroscopy, or nuclear magnetic resonance (NMR) . Some widely used nonspectral methods include differential scanning calorimetry, − differential thermal analysis, − and thermogravimetric analysis, , which reveal phase transitions in solids; optical 12,21-24 , hot-stage, and electron microscopy for morphological analysis; and X-ray powder diffraction (XRPD) − for structural analysis. Alternatively, vibrational spectroscopy, such as infrared absorption − or Raman scattering , has been used to measure the vibrational modes of solids, which contain information about structural differences of polymorphs.…”

mentioning

confidence: 99%

Characterization and Quantitation of Aprepitant Drug Substance Polymorphs by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy

et al. 2002

View full text Add to dashboard Cite

In this study, we report the use of attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FT-IR) for the identification and quantitation of two polymorphs of Aprepitant, a substance P antagonist for chemotherapy-induced emesis. Mixtures of the polymorph pair were prepared by weight and ATR-FT-IR spectra of the powdered samples were obtained over the wavelength range of 700-1500 cm(-1). Significant spectral differences between the two polymorphs at 1140 cm(-1) show that ATR-FT-IR can provide definitive identification of the polymorphs. To investigate the feasibility of ATR-FT-IR for quantitation of polymorphic forms of Aprepitant, a calibration plot was constructed with known mixtures of the two polymorphs by plotting the peak ratio of the second derivative of absorbance spectra against the weight percent of form II in the polymorphic mixture. Using this novel approach, 3 wt % of one crystal form could be detected in mixtures of the two polymorphs. The accuracy of ATR-FT-IR in determining polymorph purity of the drug substance was tested by comparing the results with those obtained by X-ray powder diffractometry (XRPD). Indeed, polymorphic purity results obtained by ATR-FT-IR were found to be in good agreement with the predictions made by XRPD and compared favorably with actual values in the known mixtures. The present study clearly demonstrates the potential of ATR-FT-IR as a quick, easy, and inexpensive alternative to XRPD for the determination of polymorphic identity and purity of solid drug substances. The technique is ideally suited for polymorph analysis, because it is precise, accurate, and requires minimal sample preparation.

show abstract