Plasma & Tissue Concentration–Time Profiles Euler ODE solver · 720 steps
Absorption Drivers
Distribution Parameters
Lipinski / Ro5
Compartment Snapshot
BCS Dimensionless Numbers Dose · Absorption · Dissolution
Run simulation to calculate.
CAT Model — GI Compartment Data Compartmental Absorption & Transit (CAT) · Human Fasted
PK Summary Table
| Parameter | Value | Unit |
|---|
Hepatic Extraction & First-Pass
Run simulation to see hepatic extraction details.
Disposition Pathway
pH-Dependent Solubility Profile
In Vitro Dissolution Profile
Particle Size Effect on Dissolution & Absorption d10 / d50 / d90 sensitivity
Dissolution time t85 vs particle size
Fraction absorbed vs particle size (PBPK)
z-Factor Dissolution Model Refined per Hofsäss & Dressman 2020
% dissolved, disintegration & available-mass band
Model parameters & diagnostics
IVIVC Development Sequence Ordered workflow — FDA 1997 / USP <1088>
Integrated model inputs — drug · formulation · system · physiology
Step 1b · Dissolution Model Fitting — Best-Fit Kinetics Fit literature models to your multipoint dissolution data
Fits 12 model-dependent dissolution kinetics (zero/first-order, Higuchi, Korsmeyer–Peppas, Hixson–Crowell, Weibull, Hopfenberg, Makoid–Banakar, Peppas–Sahlin, quadratic, logistic, Gompertz) by non-linear least squares and ranks them by AIC / adjusted-R² / MSC (Costa & Lobo 2001; Zhang 2010). The best-fit curve can drive the IVIVC and Mechanistic IVIVC.
Medium:
Observed points vs fitted curves
Step 2-3 · IVIVC — In Vitro / In Vivo Correlation Multipoint dissolution → PBPK-predicted plasma
Dissolution (%) vs Plasma Cmax-normalized (%) — correlation
Predicted plasma C(t) per dissolution medium vs reference
Step 4-6 · Mechanistic IVIVC — Deconvolution → Correlation → Validation Reference C(t) → In-vivo Ra(t) → Level A → Convolved Test
Reference Plasma C(t) & Deconvolved Ra(t)
In-vivo Fraction Absorbed — Ref vs Test (Convolution)
Level A IVIVC — In Vitro Diss. vs In Vivo Fa(t)
Levy Plot — In Vivo Time vs In Vitro Time
Predicted Tissue:Plasma Partition Coefficients (Kp) — Rodgers–Rowland Method
Step 7 · Mechanistic IVIVC — Reference vs Test (pH-resolved + experimental solubility) Enter Ref/Test pH dissolution & measured solubility, then Run
Biorelevant dissolution — Reference vs Test
Predicted plasma C(t) — Reference vs Test
Level A — % dissolved (biorelevant) vs % absorbed in vivo
Experimental pH-solubility vs Henderson–Hasselbalch
Step 8 · IVIVC Predictability Validation — % Prediction Error (FDA) Internal & external predictability of the IVIVC
%PE = (Observed − Predicted)/Observed × 100 for Cmax and AUC, per FDA IVIVC guidance (1997). Internal: mean absolute %PE ≤ 10% and each formulation ≤ 15%. External: ≤ 10% establishes predictability, 10–20% inconclusive, > 20% inadequate. Enter formulations (slow/medium/fast for internal + a separate external batch), or pull the current IVIVC prediction.
Observed vs predicted (unity line)
Food Effect — Fed vs Fasted Plasma Concentration Gastric delay + bile-salt solubilisation model
Plasma C(t): fasted vs fed (high-fat meal)
Fed/Fasted PK ratios & FDA classification