Effects of grinding and compression on crystal structure of anhydrous caffeine

Pirttimäki, Jukka; Laine, E.; Ketolainen, Jarkko; Paronen, Petteri

doi:10.1016/0378-5173(93)90394-u

Cited by 90 publications

(48 citation statements)

References 4 publications

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“…The solid form influences relevant physical-chemical parameters such as solubility, dissolution rate of the drug, chemical stability, melting point and hygroscopic parameter which can result in solids with superior properties [27,35]. In recent years, much of the research has been carried out on the preparation of pharmaceutical solid forms [6,10,24,26,28]. Usually, there are two methods by which solid forms may be prepared: solution-based crystallization and grinding.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic and physical–chemical characterization of ambazone–glutamate salt

et al. 2011

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Abstract. Ambazone monohydrate C 8 H 11 N 7 S · H 2 O (AMB), a well-known antimicrobial compound, was used together with Glutamic Acid C 5 H 9 NO 4 (Glu) to obtain a new solid form using the solvent-drop grinding procedure. The screening of the new solid form was best achieved by the combined use of X-ray Powder Diffraction (XRPD) and several spectroscopic techniques (Fourier Transformed Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), Raman and 13 C-NMR spectroscopy) together with Differential Scanning Calorimetry (DSC), Differential thermal analysis and thermogravimetry (DTA-TGA). The combination of the mentioned analytical techniques allows the compound to be assigned to an ambazone-glutamate salt which crystallizes in monoclinic system having the following lattice parameters: a = 9.8352, b = 4.7014, c = 40.0987 Å and β = 94.505• . DSC, TGA data and the before mentioned spectroscopic techniques support the ambazone-glutamate salt formation.

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Section: Introductionmentioning

confidence: 99%

Spectroscopic and physical–chemical characterization of ambazone–glutamate salt

et al. 2011

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“…Usually, there are two methods by which solid forms may be prepared: solution-based crystallization and grinding. Mechanical chemical methods [8,9,17,20,22], more commonly and usefully described as grinding, have been employed extensively in the preparation of solid forms. The range of grinding conditions has been extended by the addition of solvents in the "solventdrop" method [5] and this may represents the introduction of solution conditions on a limited scale to the grinding process.…”

Section: Introductionmentioning

confidence: 99%

Structural characterization of ambazone salt with niflumic acid

Kacsó

Rus²,

Pop

et al. 2012

Spectroscopy

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Abstract. Salt formation is a good method of increasing solubility, dissolution rate and consequently the bioavailability of poor soluble acidic or basic drugs [Polymorphism in Pharmaceutical Solids, Drugs and the Pharmaceutical Sciences, Vol. 192, 2nd edn, Informa Healthcare, New York, 2009]. The aim of this study was to obtain and to investigate the structural properties of the compound obtained by solvent drop grinding (SDG) method [Chem. Commun. (Camb.) 20 (2002), 2372-2373 at room temperature starting from the 1:1 molar ratios of ambazone (AMB) and niflumic acid (NIA). The thermal behavior of the obtained compound (AMB · NIA) was investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG), the thermal diffusivity and effusivity parameters were determined by photothermal radiometry (PTR). The structural characterization was performed with X-ray powder diffraction (XRPD) and infrared spectroscopy (FTIR). XRPD data and FTIR spectra demonstrated a new structure for AMB · NIA compound as compared to those of the starting materials.

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“…1 This is particularly important for substances of pharmaceutical interest, such as caffeine 2 or acetyl salicylic acid (ASA, also known as aspirin), 3 since different crystal forms typically exhibit different physical…”

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Relaxation in the glass former acetylsalicylic acid studied by deuteron magnetic resonance and dielectric spectroscopy

et al. 2006

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Supercooled liquid and glassy acetyl salicylic acid was studied using dielectric spectroscopy and deuteron relaxometry in a wide temperature range. The supercooled liquid is characterized by major deviations from thermally activated behavior. In the glass the secondary relaxation exhibits the typical features of a Johari-Goldstein process. Via measurements of spin-lattice relaxation times the selectively deuterated methyl group was used as a sensitive probe of its local environments. There is a large difference in the mean activation energy in the glass with respect to that in crystalline acetyl salicylic acid. This can be understood by taking into account the broad energy barrier distribution in the glass.

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Effects of grinding and compression on crystal structure of anhydrous caffeine

Cited by 90 publications

References 4 publications

Spectroscopic and physical–chemical characterization of ambazone–glutamate salt

Spectroscopic and physical–chemical characterization of ambazone–glutamate salt

Structural characterization of ambazone salt with niflumic acid

Relaxation in the glass former acetylsalicylic acid studied by deuteron magnetic resonance and dielectric spectroscopy

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