Raman and solid state13C-NMR investigation of the structure of the 1 : 1 amorphous piroxicam : ?-cyclodextrin inclusion compound

Redenti, Enrico; Zanol, Margherita; Ventura, Paolo; Fronza, Giovanni; Comotti, Angiolina; Taddei, Paola; Bertoluzza, A.

doi:10.1002/(sici)1520-6343(1999)5:4<243::aid-bspy5>3.0.co;2-c

Cited by 44 publications

(62 citation statements)

References 19 publications

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“…4. These spectra are similar to those previously reported for polymorphic forms of cimetidine (38) and piroxicam (18,29,39). The signals were assigned as described in literature in accordance with the numbering systems of cimetidine and piroxicam structures presented in Fig.…”

Section: Solid-state 13 C Cp/mas Nmr Analysessupporting

confidence: 87%

“…The distance (3.9 ppm) between the peak position of C 11 (152.6 ppm) and C 15 (148.7 ppm) for the coprecipitate is more similar to that of the uncharged form (2.1 ppm) than that of the zwitterionic form (12.5 ppm). In addition, the comparable distance (10.4 ppm) between peak position of C 11 (149.4 ppm) and C 15 (139.0 ppm) for the piroxicam monohydrate, assumed to exist as zwitterionic structure (18,40), was also reported. For piroxicam form I and piroxicam in the coprecipitate, these peaks were not resolved as shown in Fig.…”

Section: Solid-state 13 C Cp/mas Nmr Analysesmentioning

confidence: 79%

“…Regarding the solubility of crystalline cimetidine and piroxicam, the former is soluble in water whereas the latter exhibits low water solubility. Therefore, amorphous piroxicam is needed, and several preparation methods have been developed over the past decade, mostly using polymers and β-cyclodextrin (15)(16)(17)(18). In the present study, however, amorphous piroxicam was prepared by coprecipitation with cimetidine.…”

Section: Introductionmentioning

confidence: 93%

“…Generally, the combination of many analytical techniques is required to characterize the complex interactions in amorphous solid states. These techniques include PXRD (19,20), FTIR (16,19), differential scanning calorimetry (21), and solidstate NMR (18,22). Besides these experimental techniques, computational methods have also proven to be useful tools in the investigation of drug properties, and particularly in the examination of intra-and intermolecular interactions between different materials (23,24).…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Cimetidine–Piroxicam Coprecipitate Interaction Using Experimental Studies and Molecular Dynamic Simulations

2010

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Abstract. The crystalline states of cimetidine and piroxicam, when coprecipitated from solvents containing 1:1 mole ratio, were transformed to amorphous states as observed using powder X-ray diffraction (PXRD). Amorphous forms of drugs generally exhibit higher water solubility than crystalline forms. It is therefore interesting to investigate the interactions that cause the transformation of both the crystalline drugs. Intermolecular interactions between the drugs were determined using Fouriertransform infrared spectroscopy (FTIR) and solid-state 13 C CP/MAS NMR. Molecular dynamic (MD) simulation was performed for the first time for this type of study to indicate the specific groups involved in the interactions based on radial distribution function (RDF) analyses. RDF is a useful tool to describe the average density of atoms at a distance from a specified atom. FTIR spectra revealed a shift of the C≡N stretching band of cimetidine. The 13 C CP/MAS NMR spectra indicated downfield shifts of C 11 , C 15 and C 7 of piroxicam. RDF analyses indicated that intermolecular interactions occurred between the amide oxygen atom as well as the pyridyl nitrogen of piroxicam and H-N 3 of cimetidine. The hydrogen atom (O-H) at C 7 interacts with the N 1 of cimetidine. Since the MD simulation results are consistent with, and complementary to the experimental analyses, such simulations could provide a novel strategy for investigating specific interacting groups of drugs in coprecipitates, or in amorphous mixtures.

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Section: Solid-state 13 C Cp/mas Nmr Analysessupporting

confidence: 87%

Section: Solid-state 13 C Cp/mas Nmr Analysesmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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Characterization of Cimetidine–Piroxicam Coprecipitate Interaction Using Experimental Studies and Molecular Dynamic Simulations

2010

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“…The effect of the inclusion process on the guest molecules has also been the subject of some Raman studies; 4,5,6 in particular, Raman and FT-IR investigations of the interactions between CD and some non-steroidal anti-inflammatory agents (like diclofenac sodium, 7 ketoprofen 8 and amorphous piroxicam 9 ), have shown significant changes in the vibrational spectrum of the complexed guest molecules with respect to the free ones.…”

Section: Introductionmentioning

confidence: 99%

Vibrational properties of inclusion complexes: The case of indomethacin-cyclodextrin

Rossi

Verrocchio

Viliani

et al. 2006

The Journal of Chemical Physics

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Vibrational properties of inclusion complexes with cyclodextrins are studied by means of Raman spectroscopy and numerical simulation. In particular, Raman spectra of the non-steroidal, antiinflammatory drug indomethacin undergo notable changes in the energy range between 1600 and 1700 cm −1 when inclusion complexes with cyclodextrins are formed. By using both ab initio quantum chemical calculations and molecular dynamics, we studied how to relate such changes to the geometry of the inclusion process, disentangling single-molecule effects, from changes in the solid state structure or dimerization processes.

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Vibrational Spectroscopy of Carbohydrates and Glycoconjugates

Brandenburg¹,

Seydel²

2001

Handbook of Vibrational Spectroscopy

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In this contribution, an overview of infrared and Raman spectroscopic analytic work carried out with a biologically important molecular class, the sugars, is given. This comprises pure sugars, that is, mono‐, oligo‐ and polysaccharides, and glycoconjugates, the latter represented by glycolipids and glycoproteins. The contribution is divided into sections—‘General Aspects’, subdivided into ‘Chemical structures’, ‘Infrared and Raman frequencies and band assignments’, and ‘Structural polymorphism’; ‘Methodological Studies’; ‘Analyses of Carbohydrates’, subdivided into ‘Mono‐ and oligosaccharides’ and ‘Polysaccharides’; ‘Analyses of Glycoconjugates’, subdivided into ‘Glycolipids and lipopolysaccharides’, ‘Glycoproteins and other glyco‐linked compounds; and finally ‘Interaction Studies’, subdivided into ‘Sugar‐protein interaction’, ‘Sugar‐membrane and sugar‐lipid interactions’, and ‘Interactions of sugars with other agents'.

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Raman and solid state13C-NMR investigation of the structure of the 1 : 1 amorphous piroxicam : ?-cyclodextrin inclusion compound

Cited by 44 publications

References 19 publications

Characterization of Cimetidine–Piroxicam Coprecipitate Interaction Using Experimental Studies and Molecular Dynamic Simulations

Characterization of Cimetidine–Piroxicam Coprecipitate Interaction Using Experimental Studies and Molecular Dynamic Simulations

Vibrational properties of inclusion complexes: The case of indomethacin-cyclodextrin

Vibrational Spectroscopy of Carbohydrates and Glycoconjugates

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