Fig. 5

Atomic charges reveal reactive sites involved in the metabolic degradation of paracetamol. In the picture on the right, the atoms are colored according to their charge. The majority of metabolic degradation of paracetamol (glucuronidation, sulphonation, oxygenation) involves the phenolic (HO4) and amidic (HN) positions, the two most acidic protons in the paracetamol molecule (labels marked in bold) [72]. The relatively higher positive charge on these H atoms marks more active bonds compared to the rest of the molecule. In the equation of the QSPR model, q\(_{HO4}\) is the charge on the phenolic H, q\(_{O4}\) is the charge on the phenolic O, q\(_{C4}\) is the charge on the C binding the phenolic OH, and p\(_{HO4}\), p\(_{O4}\), p\(_{C4}\) and p are the parameters of the QSPR model, taken from the QSPR model 3d EEM Ouy2009_elem [58]