Table 3: Ridge regression analysis using standardized regression coefficients regarding the relationship between the dependent variable (representing the local anesthetic concentration eliciting 50% of maximum contraction) and the independent variables (representing physicochemical properties). 
 Independent variables  Standardized regression coefficient  
 Octanol/buffer partition coefficient (log [octanol/buffer partition coefficient])  −0.4701  Molecular weight (g/mol) (base form)  +0.0169  pKa (−log Ka)  −0.2068  Potency  −0.2428 


Ka: dissociation constant.
