Statistica 12 program

For the evaluation of formulation variables (the content of HPMC, NEU, and MCC) and their interaction with qualitative parameters of the powder blends and matrix tablets (flowability; tablet hardness; amount of caffeine released at 30 min, 240 min, and 360 min; gel layer thickness at 360 min; penetration force at 15 min and 360 min), factor analysis with factor rotation (varimax normalized) was used. Before the evaluation, the data were standardized to zero column mean and unit variance to reduce the effect of variables of different units. Moreover, a statistical analysis was also performed to evaluate the impact of the dissolution method on drug release characteristics (USP apparatus 2 vs. dynamic dissolution study). The evaluation was performed using the Statistica 12 program (StatSoft. Inc., Tulsa, OK, USA). Verification of the presence of remote points and verification of multidimensional normality was performed using the program QC.Expert 3.2 (TriloByteStatistical Software, Pardubice, Czech Republic).

The Statistica 12 program (StatSoft, Tulsa, OK, USA) was used for data processing. Normal data distribution was assessed using the Kolmogorov-Smirnov test. Mean values of RV duration, standard deviation, were calculated. The existence of differences between the examined groups was done by ANOVA test and p values of 0.05 or lower were considered statistically significant.

The statistical evaluation of data, including the principal component analysis (PCA), one-way Anova and post hoc tests, was performed in Statistica 12 program (StatSoft, Tulsa, OR, USA). The statistical significance of all obtained results was determined at p < 0.05.