Estimation of the degree of crystallinity in digoxin by X-ray and infrared methods

Abstract

The X‐ray procedure for estimation of the degree of crystallinity in digoxin is based upon measurement of the total X‐ray scattering and the scattering from crystalline regions of the drug. The infrared procedures are based upon measurement of the peak height ratios, 1775/1618 and 3095/1618 cm−1. Correlation between results obtained by the two methods is good. These methods are of value in the physico‐chemical characterization of digoxin, particularly as the properties may be altered by comminution.

Infrared spectroscopic studies of protein formulations containing glycine

“…A number of techniques have been used to determine the degree of crystallinity of a compound, including X-ray powder diffractometry (XRD), water sorption, isothermal microcalorimetry, FT-Raman, and infrared (IR) spectroscopy. [11][12][13][14][15][16] FTIR has been used to quantify the crystallinity of small molecules, and the results were in excellent agreement with those obtained by XRD. 12,17 A secondary goal of this study was to define means by which certain FTIR bands could be used to quantitate the amount of crystalline and amorphous glycine in a lyophilized protein formulation.…”

Room temperature sintering of polar ZnO nanosheets: I-evidence

“…Figure 4C shows that the crystals that form the nanosheet leave space for regularly distributed mesopores of about ~5 nm in size. It should also be pointed out that, in spite of the low calcination temperature used to prepare the material (210°C), the degrees of crystallinity (DOC) evaluated from the XRD patterns [29] are 63% and 78% for ZnO-M and ZnO-P, respectively. Figure 5 shows N 2 physisorption isotherms on a ZnO mass basis for the freshly calcined ZnO-M and for the same sample after being stored in lab conditions for 40 days.…”

Characterization and Quantification of Amorphous Material in Milled and Spray-Dried Salbutamol Sulfate: A Comparison of Thermal, Spectroscopic, and Water Vapor Sorption Approaches

“…X-ray powder diffraction has been previously examined as an approach to quantifying amorphous content 31,32 and the method appears in the British Pharmacopoeia (BP), 33 although it is not currently routinely used for this purpose. The BP method quantifies phases of a mixture based on the integration of intensities.…”