Parameters PCR(2)a PLS(2)b
  Nifedipine Atenolol Nifedipine Atenolol
Root mean square errors        
RMSEC 0.13 0.71 0.13 0.70
RMSECV 0.15 0.93 0.15 0.92
RMSEP 0.13 0.36 0.13 0.36
Regression parameters        
Slope 1.026 1.035 1.027 1.033
Intercept -0.305 -0.601 -0.312 -0.577
Correlation Coefficient (r ) 0.9983 0.9980 0.9984 0.9980
aThe number of PCR factors (PCs) are represented in parentheses, bThe number of PLS factors (LVs) are represented in parentheses.
Table 4: Root mean squared error of cross-validation (RMSECV), of calibration (RMSEC) and prediction (RMSEP), together with linear regression parameters of the linear relationship between the expected and the predicted values of nifedipine and atenolol in the validation set by the proposed chemometric methods.