FocusBits

⚠️Educational model only

Deterministic, simplified pharmacokinetic model; may contain modeling errors; omits variability & clinical factors. Not medical advice.

Compare mode: Total-only view.
Time: – h • Total: – ng/mL
Add a medication or pick a Quick start to see the curve.

Scaling is fully physiologic: F and V (or Vd×weight) define (S=1000,F/V) converting model mg → ng/mL. CR = biphasic (IR + delayed pulse or plateau). Lisdexamfetamine models LDX absorption, enzymatic conversion (first-order), and AMP elimination; “Yield” scales mg AMP per mg LDX.

About this theoretical pharmacokinetic simulator

This open educational tool visualizes idealized stimulant pharmacokinetic concentration-time curves under simplified, deterministic assumptions so you can experiment with release patterns and elimination half-lives.

Adjust dose, uptake shape (k), mean transit time (MTT), lags, fractions and half-lives and see immediate effects on the modeled curve (relative ng/mL scale). Concentrations scale via C = (1000·F/V)·A using either Vd×weight or absolute V.

Methylphenidate (MPH) here covers immediate-release (IR), biphasic controlled-release (CR) and OROS osmotic formulations. Modeling: IR is idealized as a single gamma-distributed uptake pulse. CR is modeled as IR + a delayed component that you can set either as a second gamma pulse or as a quasi-constant “plateau” infusion (for Spansule-like behavior). OROS is modeled as a small IR fraction plus a quasi-constant pump window. Lisdexamfetamine (LDX) is modeled as a prodrug: a single uptake (LDX absorption) followed by first-order enzymatic conversion to d-amphetamine and separate d-amphetamine elimination. Only abstract concentration-time kinetics are represented - no pharmacodynamic effects are simulated.

For specific questions (model types, scaling, variability limits, exporting) see the FAQ below. The intent is conceptual understanding - not clinical guidance.

Disclaimer: Not medical advice. Do not use for diagnosis, treatment, dosing, or timing decisions.

Frequently asked questions

Is this tool medical advice?
No. It is an educational visualization only and must not be used for diagnosis, treatment, dosing or timing decisions.
What does the model simulate?
Idealized uptake + elimination curves for IR, OROS (IR + pump), biphasic CR and lisdexamfetamine (LDX) conversion to d-amphetamine using parametric release plus first-order elimination.
Does it include variability or personalized metabolism?
No. It is deterministic (no inter/intra subject variability distributions, food effects, genetic metabolism differences, or stochastic noise layers).
Can I export and share my scenarios?
Yes. Use Share for a link or JSON, and Backup & Restore to export all saved profiles + session state.
How are concentrations scaled?
Using C = (1000 · F / V) · A with either Vd x weight or absolute V so bioavailability and distribution volume adjustments proportionally scale amplitude.
What do IR, CR and OROS mean?
All of these are formulations of Methylphenidate (MPH).
Methylphenidate IR = Immediate Release (single uptake pulse).
Methylphenidate CR (biphasic) = Controlled Release with a fast IR fraction followed by a delayed component that can be either a second gamma pulse or a plateau-style infusion, approximating biphasic products.
Methylphenidate OROS = Osmotic Release Oral System: small IR fraction plus a near-constant (configurable shape) pump-driven release over a defined window.