Critical review of methods for the determination of purity by differential scanning calorimetry*

Novel nanosized formulations of two diclofenac acid polymorphs to improve topical bioavailability

“…Thermograms of the four nanosuspensions are very similar and they are all characterized by a broad peak with T peak centered around 148-158°C. This behavior, lower T peak and broader peak compared to that of bulk powders, is in agreement with the Van't Hoff equation (Palermo and Chiu, 1976) and is expected for intimate mixtures like nanosuspensions. Slight differences in T peak (and T onset ) of the nanosuspension formulations can be due to the slight differences in the average particle size and PI, in agreement with the XRDP results.…”

Thermoanalytical investigations on kinetics and mechanism of deamination of tris(ethylenediamine)copper(II) sulphate

“…The higher values of activation energy from DTA technique may be due to the lag in the measurements of temperature as compared to mass measurements. Similar observations has been made by several authors [21][22].…”

Comparative analysis of purity determination methods using a differential scanning calorimeter

“…Finally, it is necessary to note that in papers [3], [6] and [7] it is recommended to correct the recorded melting curve using the melting curve slope for an indium sample. This means that the curve to be used in further treatment is obtained from the recorded melting curve through the following procedure.…”

“…This is based on a mathematical model including the construction of theoretical melting curves for two-component systems and the calculation of recorded melting curves with the help of a set of equations describing the formation ofa DSC output signal. It is shown that the true accuracy of purity determinations in the range of impurity concentrations ~ = 0.005-0.02 does not exceed 30-50%.Purity determination is a very valuable and important application of DSC that has been subject of several reviews [2], [6][7][8][9][10], but the problem of establishing the true accuracy of DSC purity determinations has not yet been solved. This was convincingly demonstrated in [7] and [8], where it was shown that the relevant publications include obviously overstated estimates of accuracy as well as recommendations to apply DSC only for determination of the order of the impurity concentration.…”