Differential scanning calorimetry purity

CRYOSCOPIC AND DIFFERENTIAL SCANNING CALORIMETRY PURITY DETERMINATION... 

Differential Scanning Calorimetry (Fig. 9) can be used to evaluate the purity of tetrabromodipentaerythritol, a tetrabrominated derivative of dipentaerythritol. Even so, the validity of the results depends on the purity of the sample. The results shown here should be considered extremely borderline. The brorainated derivatives of the pentaerythritols cannot be analyzed with this technique because of the inherent limitations of DSC. 

Differential scanning calorimetry cannot be applied to quantify the purity of the drug substance for the reasons mentioned in 2.31 and 2.34. However, it may be valuable in qualitative comparisons from sample to sample or batch to batch on the basis of their corresponding differential scanning calorimetry patterns. 

Thermal methods have found extensive use in the past as part of a program of preformulation studies, since carefully planned work can be used to indicate the existence of possible drug-excipient interactions in a prototype formulation [2], It should be noted, however, that the use of differential scanning calorimetry (DSC) for such work is less in vogue than it used to be. Nevertheless, in appropriately designed applications, thermal methods of analysis can be used to evaluate compound purity,... 

Plato, C. and Glasgow, A.R., Jr. Differential scanning calorimetry as a general method for determining the purity and heat of fusion of high-purity organic chemicals. Application to 95 compounds, Anal. Chem., 41(2) 330-336, 1969. 

NIRA provides a non-destructive alternative to differential scanning calorimetry for the determination of polymorphic forms of drugs, e.g. the polymorphic forms of caffeine. NIRA has also been used to determine optical purity. While the pure opposite enantiomers of a substance have identical NIR spectra, mixing two... 

Donnelly, J.R., L.A. Drewes, R.L. Johnson, W.D. Munslow, K.K. Knapp, and G.W. Sovocool, 1990. Purity and heat of fusion data for environmental standards as determined by differential scanning calorimetry. Thermochim. Acta 167 155-187. 

PHOSPHOLIPID SYNTHESIS. Phospholipids were synthesized (H.Schuster, S.S. Hall, and R.Mendelsohn, in preparation) according to the procedures of Tulloch (26), modified with more modern and efficient coupling steps, and scaled up to produce 2-3 grams of specifically deuterated material. Derivatives were fully characterized with NMR, MS, FT-IR, and Differential Scanning Calorimetry (DSC). Purity is estimated from NMR data at > 98X. The extent of deuteration, as estimated from the residual intensity of the CHD rocking modes at... 

Differential scanning calorimetry (DSC) The method to measure the heat flow to a sample as a function of temperature. It is used to measure, for example, specific heats, glass transition temperatures, melting points, melting profiles, degree of crystallinity, degree of cure, and purity. 

Differential scanning calorimetry is a well known technique in the study of the thermal behavior of lipids and can be used to assess purity and stability of lipids, perturbation of aggregate structures, phase transition temperatures, lipid mixing behavior, and influence of other molecules and ions on structure. ... 

In most cases, the purity of a pharmaceutical substance is determined by comparison of the reference standard with the known purity assigned. On the other hand, when no reference standard sample is available, the purity is determined by an absolute method in which the calculated result is based on theory and not by a comparative method. Purity established by analytical methods such as phase-solubility analysis or differential scanning calorimetry (DSC) is known as absolute purity (Figs. 3 and 4). 

The determination of the enantiomeric purity of many organosilanes has been achieved by the method of differential scanning calorimetry devised by Jacques, Fouquey, and colleagues (93, 94) this method is of wide applicability and high precision. 

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