Table 1. Characteristics of a pharmacokinetic pathway.

Characteristic	Description
Drug	active drug, prodrug (activating enzyme)
Metabolic element	inactive metabolite, active metabolite
Protein	enzyme (e.g., activating enzyme), transporter, carrier
Background anatomical organs	eye, nose, mouth, brain, blood-brain-barrier, lung, heart, muscle, skin, kidney, liver, adrenal gland, testis, intestines, and placenta
Transport structures	blood vessels (e.g., arteries and veins), bile ducts, and excretory tracts (e.g., urinary tract for urine, gut lumen for feces)
Methods of administration	eye drop, inhalation, sublingual and buccal absorption, oral ingestion, intravenous injection, intramuscular injection, and percutaneous absorption
Interaction types (from DrugBank)	metabolism, transportation, binding, excretion
Action types (from DrugBank)	inhibition, induction, substrate
Tissue site for ADME	expression levels of enzymes and transporters through the ProteinAtlas database

Methods of administration: the location where the drug is administered; Interaction type: the protein role, according to which the reaction between a drug and a gene happens; Action type: the type by which a drug acts to a protein or vice versa; ADME: an abbreviation in pharmacokinetics for Absorption, Distribution, Metabolism, Excretion; DrugBank version, 5.0.1.