Tmax Calculator
Restricted first order oral onecompartmentBateman tmax=ln(ka/ke)/(ka−ke), different positive matched rates. Lag/repeated dosing/multiple compartments excluded. All patient/product/route/units and applicable inputs independently clinically established; no dose, route, frequency, eligibility, titration, diagnosis or permission to administer is supplied.
Description
Time to maximum concentration depends on both absorption and elimination in a one-compartment oral model.
Time to maximum concentration depends on both absorption and elimination in a one-compartment oral model.1
This tool estimates that time from independently established first-order rate constants, under the model's no-lag assumption.
When to use Tmax Calculator
This tool estimates that time from independently established first-order rate constants, under the model's no-lag assumption.
How to use Tmax Calculator and how it works
- Prepare fitted absorption rate per hour, fitted elimination rate per hour, using the input definitions and matching units below.
- Enter the required fields and run Tmax Calculator.
- Read result.value using the units, signs and ordering explained below.
- Correct any rejected inputs and rerun; interpret the result within the stated model and its assumptions.
| Input field | Meaning | Value type | Requirement |
|---|---|---|---|
| callerFittedAbsorptionRatePerHour | Caller Fitted Absorption Rate Per Hour. Use the units and matching context stated in the calculation below. | number | Required; strictly positive; finite; other constraints below |
| callerFittedEliminationRatePerHour | Caller Fitted Elimination Rate Per Hour. Use the units and matching context stated in the calculation below. | number | Required; strictly positive; finite; other constraints below |
Require positive absorption ka and elimination ke in reciprocal hours, with ka distinct from ke. Calculate ln(ka/ke)/(ka-ke) and return hours. The implementation rejects the equal-rate case rather than using its limiting formula. Rates must be independently established for a one-compartment, first-order absorption and elimination model with no lag; multiple-dose, distribution and delayed-absorption effects are not modeled.
timeHours=ln(ka/ke)/(ka-ke) Apply the input ordering, units and branch conditions stated above.
| Output field | Meaning | Value type |
|---|---|---|
| result | Object containing the calculated or selected fields below. | object |
| result.value | Hours under the distinct-rate oral model. | number |
{
"input": {
"callerFittedAbsorptionRatePerHour": 2,
"callerFittedEliminationRatePerHour": 1
},
"output": {
"result": {
"value": 0.6931471805599453
}
}
}Limitations and assumptions
Patient context, drug formulation, route, sampling time, assay units and applicable clinician-verified protocol must be independently established. The output supplies no dosing, titration, switching or administration instruction.
The calculation uses the supplied observations and model inputs. It does not collect measurements, select a reference population or coefficient, or establish that the model applies to the actual case. The stated branch conditions and output units remain part of the result.
All fields require explicit values. Unexpected fields, wrong types, nonfinite numbers and sparse arrays are rejected. Alignment, bounds and supported-token rules are explained above; extremely large inputs or nonfinite results can also fail. Input errors differ from successful false comparisons, unavailable-domain flags and empty match lists.
Alternative or Complementary methods
Use Ke Rate Constant Calculator for a complementary operation: In a one-compartment first-order model, elimination rate constant relates clearance to distribution volume.
Use Cmax From Dose Calculator for a complementary operation: An instantaneous well-mixed bolus model gives initial concentration as available systemic mass divided by distribution volume.
References
-
Tmax Calculator — tool.io
Similar or alternative tools
- Ke Rate Constant Calculator
In a one-compartment first-order model, elimination rate constant relates clearance to distribution volume.
- Cmax From Dose Calculator
An instantaneous well-mixed bolus model gives initial concentration as available systemic mass divided by distribution volume.