Schematic representation of the pharmacokinetic model used to analyze the combined S-ketamine and S-norketamine data. V1,ket, V2,ket and V3,ket are the three ketamine (ket) compartments, V1,nkt and V2,nkt the two norketamine (nket) compartments. M1-3 represents three sequential metabolism compartments. Cl1,ket is the clearance from compartment V1,ket, Cl2,ket the clearance from compartment V2,ket, Cl3,ket the clearance from compartment V3,ket, Cl1,nkt the clearance from compartment V1,nkt and Cl2,nkt is the clearance from compartment V2,nkt. ClM is the S-ketamine clearance responsible for the S-norketamine formation.