MODELS OF DRUG ADMINISTRATION AND DISPOSITION
In the following image , the effect of drug added via intravenous drug administration is shown by adding a known amount of the drug into the beaker and the graph besides shows the time course of the amount of drug in the beaker. (CR : Basic and Clinical Pharmacology, Katzung, Lange, 12th Edition) Example (A): no movement of drug out of the beaker --> a steep rise to maximum followed by a plateau. Example (B): a route of elimination is present --> a slow decay after a sharp rise to a maximum; level of material in the beaker falls --> “pressure” driving the elimination process also falls --> slope of the curve decreases : Exponential decay curve. Example (C) : drug placed in first "blood" compartment - equilibrates rapidly with second "extravascular" compartment --> amount of drug in “blood” declines exponentially to a new steady state. Example (D): model for a more realistic combination of elimination mechanism and extravascu...