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Stability Study Design Calculator

Calculate total sample count from time points, conditions, tests, replicates, and batches per ICH Q1A(R2).

Inputs

%

Results

Total samples needed

594

Test samples540
Retain samples54
Samples per pull10
Total sampling events54
Estimated total volume (L)3
How to Use This Calculator
  1. Enter the number of sampling time points and storage conditions in the study.
  2. Set tests per pull, replicates per test, number of batches, and retain sample percentage.
  3. Review Total Samples Needed, Test Samples, Retain Samples, and Total Sampling Events.
  4. Use Estimated Total Volume (L) to plan bulk drug substance or drug product requirements for the study.

How the result changes with Time points

Time pointsTotal samples needed
5.9594
181,782
333,267
454,455

What each input means

Time points
Number of sampling time points (e.g., 0, 3, 6, 9, 12, 24 months = 6 points).
Storage conditions
Number of storage conditions (e.g., accelerated, intermediate, long-term = 3).
Tests per pull
Number of analytical tests per sample pull (e.g., assay, impurities, pH, dissolution, appearance).
Replicates per test
Number of replicates for each test (typically 2-3).
Number of batches
Number of production batches to test (ICH recommends minimum 3).
Retain samples (%)
Additional percentage of samples for retention/reference.

What each result means

Total samples needed
Grand total including test and retain samples.
Test samples
Total samples required for analytical testing.
Retain samples
Additional retain/reference samples.
Samples per pull
Number of samples needed at each time point per condition per batch.
Total sampling events
Total number of individual sampling events across the study.
Estimated total volume (L)
Estimated total sample volume assuming 5 mL per sample.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Time points = 6, Storage conditions = 3, Tests per pull = 5, Replicates per test = 2 = 6 input(s) provided
  2. Calculate Total samples needed
    Total samples needed = totalTestSamples + retainSamples
    594 = 594
  3. Calculate Test samples
    Test samples = samplesPerPull * timePoints * conditions * batches
    540 = 540
  4. Calculate Retain samples
    Retain samples = ceil(totalTestSamples * (retainSamplePct / 100))
    54 = 54

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