RESUMEN
In the present paper the crystallographic behavior of the carbamazepine modifications I, II and III were studied under various conditions by means of X-ray powder diffraction, IR-spectroscopy and differential-scanning-calorimetry. It was found that the crystal lattice of the carbamazepine modification I is relative stable to the applied pressure forms, whereas modification II under similar conditions undergoes a polymorphic transformation into carbamazepine modification III, the extent of which depends on compression pressure and storage time of the tablets. In the compression samples of carbamazepine modification III neither IR-spectroscopically nor X-ray-diffractionally an influence of the pressure could be found on growing up of the enantiotrophic modification I.
Asunto(s)
Carbamazepina/análisis , Rastreo Diferencial de Calorimetría , Fenómenos Químicos , Química Física , Cristalización , Presión , Espectrofotometría Infrarroja , Difracción de Rayos XRESUMEN
The modifications and spray dried products of tolbutamide published in a former article, are investigated furthermore by X-Ray diffraction. The indication of the reflexes in X-Ray diffraction patterns of 2 modifications is performed. Transformations of modification are provable in consequence of thermal stress.
Asunto(s)
Tolbutamida/análisis , Cristalización , Polvos , Comprimidos , Difracción de Rayos XRESUMEN
In the present paper the interconversion behavior of the carbamazepine modifications I, II and III under various grinding conditions (variation of milling aggregates, milling times and frequencies) were studied. Mechanical treatment of different crystal forms led to a uniform grinding product, which is characterized crystallographically as modification III. The kinetic of phase transformations were determined by means of various quantitative methods such as a IR-spectral, a X-ray-powder diffractional and a thermoanalytical one. The results obtained by different analytical methods accorded quite well.
Asunto(s)
Carbamazepina/análisis , Química Farmacéutica , Composición de Medicamentos , Espectrofotometría Infrarroja , Temperatura , Factores de Tiempo , Difracción de Rayos XRESUMEN
The insoluble X-ray diagnostic iomeglamic acid could be converted to a more soluble modification by melting and solidifying it in liquid nitrogen. The amorphous state is proved by X-ray diffraction and differential thermal analysis. During storage, recristallisation of the product appears. By means of the proved amorphous state, it seems possible to determine the amount of the amorphous state, which makes the drug more soluble from solid dispersions.