Estudo de compatibilidade entre atorvastatina e excipientes por técnicas térmicas (TG, DSC) e FTIR utilizando correlação de pearson

Abstract

Atorvastatin is an antilipemic drug from the statins’ group that has a great importance to prevent cardiovascular disease and it is usually used as atorvastatin calcium. The aim of this study was to characterize the atorvastatin and studying possible interactions with different excipients by DSC, TG and FTIR. DSC curves were obtained using a Shimadzu calorimeter, model DSC-60, aluminum pan, under heating rate of 20 ºC min-1 at temperature of 25-400 ºC. Consequently, curves were analyzed using TASYS software from Shimadzu. The spectra of the samples were obtained on a spectrophotometer ATR-FTIR (IRPrestige- 21 Shimadzu), between 700 and 4000 cm-1, on average of 20 scans. We evaluated the atorvastatin and binary mixtures’ spectral steadiness by making a linear correlation between the theoretical spectra and the real ones obtained at room temperature (25 °C). The theoretical spectra were obtained using an ad hoc algorithm. We evaluated by DSC that there are chemical interactions with mannitol and sodium lauryl sulfate because there was disappearance of the drug’s peak and appearance only of the excipients’ peaks. With respect to the other excipients, there were only displacements of peaks suggesting physical interactions, it means no incompatibility. From the FTIR evaluation using Person’s correlation, it was not observed any physical interaction between atorvastatin and the following excipients: starch glycolate, pregelatinized starch, croscarmellose, magnesium stearate and lactose, since the value of r was between 0.8 and 1.0; in other words, it means a good correlation. Moreover, it was confirmed a physical interaction with the sodium lauryl sulfate. Finally, the results obtained by DSC were confirmed by FTIR data using the Person’s correlation, so both analytical techniques demonstrated to be extremelly important and effective tools for applying in a preformulation study.