A pharmaceutical active compound, chloramphenicol palmitate, appears in three polymorphic forms, that can be observed at room temperature. The stable form A (biologically inactive modification), the meta-stable form B (active modification) and unstable form C were found to have distinct Raman spectra, with bands attributable to the different polymorphs. The use of hot-stage Raman microscopy (the direct coupling of Raman microscopy and hot-stage) is demonstrated for the drug substance chloramphenicol palmitate form C. All modifications of form C were produced and identified by hot-stage Raman microscopy. A close correlation of thermal and spectroscopic information was achieved by this combination of techniques. As reported in several pharmacopoeias, the content of form A should be less than 10%; therefore, a mixture of 10% (w/w) A in B was prepared, and the presence of the characteristic bands of form A after subtraction of the pure B was revealed. Moreover, mixtures between 2 and 12% (w/w) A in B were investigated and the intensity ratio (as peak area) I413–435/I1035–1158 as a function of A percentage has been demonstrated to show a linear trend. Other methods for the characterization of polymorphs were used: Fourier transform infrared spectroscopy (FT-IR), Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD).

Solid state characterization of Chloramphenicol Palmitate. Raman spectroscopy applied to pharmaceutical polymorphs.

TINTI, ANNA;
2006

Abstract

A pharmaceutical active compound, chloramphenicol palmitate, appears in three polymorphic forms, that can be observed at room temperature. The stable form A (biologically inactive modification), the meta-stable form B (active modification) and unstable form C were found to have distinct Raman spectra, with bands attributable to the different polymorphs. The use of hot-stage Raman microscopy (the direct coupling of Raman microscopy and hot-stage) is demonstrated for the drug substance chloramphenicol palmitate form C. All modifications of form C were produced and identified by hot-stage Raman microscopy. A close correlation of thermal and spectroscopic information was achieved by this combination of techniques. As reported in several pharmacopoeias, the content of form A should be less than 10%; therefore, a mixture of 10% (w/w) A in B was prepared, and the presence of the characteristic bands of form A after subtraction of the pure B was revealed. Moreover, mixtures between 2 and 12% (w/w) A in B were investigated and the intensity ratio (as peak area) I413–435/I1035–1158 as a function of A percentage has been demonstrated to show a linear trend. Other methods for the characterization of polymorphs were used: Fourier transform infrared spectroscopy (FT-IR), Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD).
M.C. Gamberini; C. Baraldi; A. Tinti; C. Rustichelli; V. Ferioli; G. Gamberini
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/39544
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 29
  • ???jsp.display-item.citation.isi??? 28
social impact