The influence of sample preparation and the presence of other active pharmaceutical ingredients (api) and excipients on the use of dsc method in quantification of paracetamol in commercially available tablets

The direct Differential Scanning Calorimetry method of the determination of paracetamol in commercially available drugs was developed. The method was based on calibration curves obtained from melting enthalpies ΔH of binary mixtures of paracetamol and commonly used excipients such as starch or microcrystalline cellulose in increasing weight ratios. In order to demonstrate how the technological processes of formulating the tablets affects the quantitative studies, the micronized and nonmicronized mixtures were used. The idea of using micronized mixtures was to simulate these technological processes. The appropriate paracetamol contents of the selected pharmaceutical preparations were calculated and compared. The final results demonstrated, that the contents of paracetamol obtained from micronized samples were much closer to those declared by the manufacturer than the nonmicronized. Excluding two drugs, the influence of starch or cellulose on quantification in the micronized group was not observed whereas in the nonmicronized group it was distinctly visible.