Permeability & Efflux Calculator
Calculate bidirectional Papp, efflux ratio, and uptake ratio from dQ/dt.
Permeability results
Enter finite values greater than zero in every field.
dQ/dt must be the slope of the linear steady-state region of cumulative amount appearing in the receiver versus time. Enter the actual donor C₀ for each direction. Separately review sink conditions, mass balance/recovery, monolayer integrity, transporter expression, and assay validation. This tool does not set an automatic permeability or efflux acceptance threshold.
Sources: ICH M9 Annex I; NIH Molecular Libraries Probe Reports (Caco-2 permeability methods).
Tool Guide
Definition
Permeability & Efflux Calculator — Use the linear slope dQ/dt of cumulative amount appearing in the receiver, membrane area A, and initial donor concentration C₀ to calculate bidirectional apparent permeability coefficients (Papp) and the B→A/A→B efflux ratio.
Purpose
(1) Cross-check bidirectional Caco-2 or MDCK transport results (2) Convert mixed nmol/min, µM, and cm² units (3) Prepare A→B and B→A Papp plus efflux-ratio values for reports (4) Catch calculation errors before comparing compounds
How to Use
① Choose effective membrane area and transported-amount/time units. ② Enter the linear dQ/dt and actual donor C₀ for each A→B and B→A direction. ③ Copy Papp (×10⁻⁶ cm/s), efflux ratio, and uptake ratio. dQ/dt is cumulative amount per time. If starting from a concentration/time slope, first multiply by receiver volume to obtain amount/time.
Examples
Example) A=0.33 cm², C₀=10 µM, dQ/dt A→B=0.002 nmol/min and B→A=0.006 nmol/min → Papp A→B=10.101×10⁻⁶ cm/s → Papp B→A=30.303×10⁻⁶ cm/s → efflux ratio=3, uptake ratio=0.333 These are calculated values; assay-specific acceptance is separate.