Thermal analysis methods for pharmacopoeial materials

Overlap between Frontotemporal Dementia and Alzheimer's Disease: Cerebrospinal Fluid Pattern and Neuroimaging Study

“…This may be attributable to the presence of impurities in the purchased propyphenazone which may be of any related substance or of a different polymorphic form of propyphenazone since existence of 2-3 different polymorphic forms of propyphenazone with melting points within the range of 101-104.3°C (T m ) has been reported in the literature. 5,10) The observed melting point of 100°C (T m 104°C) is in agreement with other literature reports. 5,10) The exothermic peak obtained at 49°C during cooling is probably due to recrystallization of the melted propyphenazone.…”

“…5,10) The observed melting point of 100°C (T m 104°C) is in agreement with other literature reports. 5,10) The exothermic peak obtained at 49°C during cooling is probably due to recrystallization of the melted propyphenazone. Peaks with T m s at 101°C and 104°C observed during the reheating process closely correspond to melting temperatures of two different polymorphic forms of propyphenazone, form III and form I, respectively, which were reported to form as a result of melting of a commercial grade (form II) of propyphenazone.…”

“…Peaks with T m s at 101°C and 104°C observed during the reheating process closely correspond to melting temperatures of two different polymorphic forms of propyphenazone, form III and form I, respectively, which were reported to form as a result of melting of a commercial grade (form II) of propyphenazone. 5) Similar complex endothermic behaviour was observed for mixtures of the polymorphic forms I and II of propyphenazone by Giron-Forest et al 10) These results are supported by the data we obtained from Xray powder diffraction analysis for propyphenazone before and after the melting process. But the identical DSC thermograms obtained during first heating of the melted (then cooled to room temperature and stored for at least 30 d) propyphenazone to the untreated sample suggest the polymorphs produced during the melting process were metastable and converted to form II during storage of the cooled sample.…”

Thermal behavior of a pharmaceutical solid acetaminophen doped withp-aminophenol

“…van-Dooren and Muller [ 4] have suggested a number of important conditions in the experimental setting of DSC purity determination, most of which were satisfied in this study. These conditions may make it difficult to use the DSC method as an official method of purity determination of pharmaceuticals [10].…”

Water Content Using Karl-Fisher Aquametry and Loss on Drying Determinations Using Thermogravimeter for Pesticide Standard Materials

“…As an advantage, the required minimum sample weight is small (generally 1-20 mg) with a high reproducibility. [2][3][4][5] As a drawback, the measurement time is relatively long and a liquid sample is not proper for LOD using TGA. KF measures the water content in a sample.…”