Relative Bioavailability Calculator

Relative dose-normalized bioavailability against actual SAME route reference formulation, not absolute IV bioavailability. 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

Relative bioavailability compares dose-normalized exposures between matched formulations using the same route.

Relative bioavailability compares dose-normalized exposures between matched formulations using the same route.^[1]

This tool calculates the test-to-reference ratio without treating the reference automatically as intravenous absolute availability.

When to use Relative Bioavailability Calculator

This tool calculates the test-to-reference ratio without treating the reference automatically as intravenous absolute availability.

How to use Relative Bioavailability Calculator and how it works

Prepare test auc, test dose mass, reference auc, reference dose mass, using the input definitions and matching units below.
Enter the required fields and run Relative Bioavailability 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
actualTestAuc	Actual Test Auc. Use the units and matching context stated in the calculation below.	number	Required; nonnegative; finite; other constraints below
actualTestDoseMass	Actual Test Dose Mass. Use the units and matching context stated in the calculation below.	number	Required; strictly positive; finite; other constraints below
actualReferenceAuc	Actual Reference Auc. Use the units and matching context stated in the calculation below.	number	Required; strictly positive; finite; other constraints below
actualReferenceDoseMass	Actual Reference Dose Mass. Use the units and matching context stated in the calculation below.	number	Required; strictly positive; finite; other constraints below

Require nonnegative test AUC and positive test dose, reference AUC and reference dose. Divide each AUC by its corresponding dose, then divide test exposure per dose by reference exposure per dose. Return a dimensionless relative ratio without clipping to one; formulation, same-route context and matched dose/AUC units must be independently established.

relativeF=(testAuc/testDose)/(referenceAuc/referenceDose)

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	Numeric model result on the ratio, score, constant or density basis explained above.	number

json

{
  "input": {
    "actualTestAuc": 2,
    "actualTestDoseMass": 2,
    "actualReferenceAuc": 4,
    "actualReferenceDoseMass": 2
  },
  "output": {
    "result": {
      "value": 0.5
    }
  }
}

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 Tmax Calculator for a complementary operation: Time to maximum concentration depends on both absorption and elimination in a one-compartment oral model.

Use Ke Rate Constant Calculator for a complementary operation: In a one-compartment first-order model, elimination rate constant relates clearance to distribution volume.

References

Relative Bioavailability Calculator — tool.io

Similar or alternative tools

Tmax Calculator
Time to maximum concentration depends on both absorption and elimination in a one-compartment oral model.
Ke Rate Constant Calculator
In a one-compartment first-order model, elimination rate constant relates clearance to distribution volume.