PBPK Compartment Model: 2D Drug Distribution Simulator

Dose

IV bolus dose 200 mg

Drug Properties

Lipophilicity (logP-like) 4.0

Hepatic (CYP) clearance 1.0×

Renal clearance 1.0×

Simulation speed 1.0×

Central Compartment

Blood concentration

0.0 mg/L

Elapsed time

0.0 min

Dose eliminated

0.0 %

Tissue Concentrations

Liver

0.0 mg/L

Kidney

0.0 mg/L

Fat

0.0 mg/L

Rest of body

0.0 mg/L

How it works

This is a real flow-limited PBPK (physiologically-based pharmacokinetic) model rendered as a 2D schematic. Blood is pumped through four tissue compartments at their real fraction of cardiac output; each tissue is assumed to equilibrate instantly with the blood leaving it, scaled by its drug/tissue partition coefficient K_p:

dA_blood/dt = Σᵢ Qᵢ·(Cᵢ/Kpᵢ − C_blood)
dAᵢ/dt      = Qᵢ·(C_blood − Cᵢ/Kpᵢ) − CLᵢ·(Cᵢ/Kpᵢ)
Cᵢ = Aᵢ / Vᵢ    (tissue concentration)
CL_liver = hepatic slider × 0.9 L/min
CL_kidney = renal slider × 0.6 L/min

Blood flow is split the way it really is in an adult (cardiac output ≈ 5 L/min): liver 1.35 L/min, kidney 1.1 L/min, fat 0.25 L/min, everything else (muscle, skin, etc.) 2.3 L/min. Lipophilicity raises every K_p — especially fat's, which is why lipophilic drugs accumulate in adipose tissue for a slow, delayed release, while hydrophilic drugs stay confined to blood and lean tissue.

Hepatic clearance only removes drug while it's inside the liver compartment (CYP450 metabolism) — raise it and the liver empties itself faster instead of returning drug to blood.
Renal clearance does the same from the kidney compartment (glomerular filtration + secretion).
Dots flowing along the diagram are drug molecules riding the blood between the central pool and each organ; their brightness and size track the local concentration. The strip chart below plots every compartment's concentration against elapsed time, so you can watch distribution and elimination unfold numerically as well as visually.
Drag the diagram to pan, scroll/pinch to zoom — the schematic is a free-floating hub-and-spoke layout, not a fixed picture.

This is the same organ-by-organ approach used in real PBPK software (e.g. Simcyp, GastroPlus) to predict tissue exposure before a drug ever reaches a clinical trial.

t = 0.0 min

drag to pan · scroll to zoom

Blood (central) Liver Kidney Fat Rest of body