Spectral Methods for Determination of Water

Solid state characterization of mometasone furoate anhydrous and monohydrate forms

“…Those characteristic bands reflect ''tightly bound'' water or crystalline water, which are observed for numerous hydrates. 11,[15][16][17] This is confirmed by the crystal structure of the monohydrate. The water molecule is tightly bound to mometasone furoate molecules with three types of hydrogen bonding.…”

“…It can be classified as a channel hydrate. 10 Similar structural characteristics are also present in crystals of ampicillin trihydrate, 11 caffeine hydrate, 12 theophylline hydrate, 13 and thymine hydrate. 14 Each water molecule forms three hydrogen bonds with neighboring mometasone furoate molecules in the crystal structure as listed in Table 3 and illustrated in Scheme 2.…”

Investigation of the solid state properties of amoxicillin trihydrate and the effect of powder pH

“…20 This may highlight the importance of the hydrated crystal structure in physical stability of AMT powder, which is similar to the report by Brittain and his colleagues for ampicillin trihydare. 17 However, the intensity of the peaks for the same quantity of AMT with pH 4.97 was noticeably higher than that for AMT powder with pH 4.39, which has not been reported previously. From this finding it can be concluded that a direct relationship between the powder pH and the degree of crystallinity in the above mentioned samples exists, probably because of different crystallization conditions and the status of crystallization for AMT molecules in the pH 4.97 samples.…”

“…12 Solid state properties of pharmaceutical compounds have been increasingly reported using experimental techniques, such as powder x-ray diffraction (PXRD), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and thermogravimetry analysis (TGA). [13][14][15][16][17] Different solid forms of the same chemical compound can exhibit different physical and chemical properties including different solubility and dissolution profiles, which in turn affect the bioavailability and stability of the drug substance.…”

Art of Synthesis of Desired Polymorphs: A Review

“…Studies carried out in the high-energy region of the infrared spectra yields spectral differences between solvated phase and the anhydrous phase. When water acts as a solvation agent, the frequencies at 3600-3100 cm -1 are found to be mostly affected, as observed in the case of digoxin [84], ampicillin [85] and trazodone hydrochloride [86]. Organic solvents also induce appreciable changes in the high-energy spectral region.…”