Compatibility study between atorvastatin and excipients using DSC and FTIR

The aim of this study was to characterize atorvastatin and evaluate interactions between atorvastatin and various excipients by DSC and FTIR, using Pearson's correlation as a tool to corroborate possible interactions that it was not possible to evidence in visual analyses. The DSC curves were obtained using a Shimadzu calorimeter, Model DSC-60, in the aluminum crucible under heating rate of 20 A degrees C min(-1) at a temperature of 25-400 A degrees C. The spectra of the samples were obtained on a FTIR-ATR model IR prestige-21 Shimadzu spectrophotometer at a wavelength of 700-4000 cm(-1) on average of 20 scans. The theoretical spectrum was obtained using an ad hoc algorithm. From the analysis of DSC and evaluation of Pearson's correlation, it observed physical interactions with excipients: starch glycolate, pre-gelatinized starch, croscarmellose, sodium lauryl sulfate, magnesium stearate and mannitol. There is no interaction with lactose. Then, the Pearson's correlation was so important tool to evaluate possible interactions between IPAs and excipients, using FTIR data to corroborate DSC results.