Pharmaceutical quality · Comparative dissolution
Dissolution Profile Evaluator
Enter product details and individual unit dissolution results to calculate the f₂ similarity factor and f₁ difference factor, review variability, and visualize test-versus-reference dissolution profiles.
1. Product and study information
Identify the test and reference products and document the dissolution conditions.
2. Dissolution data entry
Enter individual vessel/unit percentages dissolved for each time point. Separate values with commas, spaces, or line breaks.
Example entry for 12 units: 18.2, 19.1, 20.0, 18.7, 19.4, 20.1, 18.9, 19.8, 20.2, 19.0, 18.5, 19.6. Use cumulative percentage dissolved, not concentration. Use matching time points and the same conditions for both products.
| Time (min) | Reference individual results (% dissolved) | Test individual results (% dissolved) | Include in f₁/f₂ | Action |
|---|
Tip: Paste the replicate results for each time point directly into the relevant cell. Each row calculates its own mean, sample SD and CV% after evaluation.
3. Evaluation results
f₂ similarity factor, f₁ difference factor, descriptive statistics and profile assessment.
Similarity factor · f₂
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Awaiting data
Difference factor · f₁
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Lower values indicate less difference
Time points used
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Selected non-zero time points
Unit count
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Minimum commonly 12 per product
Enter dissolution data, then select “Calculate evaluation”.
Time-point summary
| Time | Ref mean | Ref SD | Ref CV% | Test mean | Test SD | Test CV% | Difference | Used? |
|---|---|---|---|---|---|---|---|---|
| No results calculated yet. | ||||||||
Calculations use the arithmetic mean of individual unit results at each selected time point. SD is sample standard deviation (n−1). CV% = SD / mean × 100.
4. Dissolution profile graph
Mean cumulative percentage dissolved against sampling time.
Reference meanTest mean85% reference line
5. Formula and interpretation
Model-independent comparison of two mean dissolution profiles.
Similarity factor (f₂)
f₂ = 50 × log₁₀ { [1 + (1/n) Σ(Râ‚œ − Tâ‚œ)²]⁻⁰·⁵ × 100 }
Rₜ and Tₜ are the mean percentages dissolved for the reference and test products at time t; n is the number of included sampling time points.
Difference factor (f₁)
f₁ = { Σ |Râ‚œ − Tâ‚œ| / Σ Râ‚œ } × 100
f₁ describes the relative average absolute difference. It is supportive/descriptive; f₂ is the commonly applied similarity statistic. Do not treat f₁ as a universal standalone acceptance criterion.
Interpretation: f₂ from 50 to 100 generally indicates similar dissolution profiles under the applicable method conditions. f₂ below 50 means similarity has not been demonstrated by this statistic. It does not, by itself, establish bioequivalence, therapeutic equivalence, or interchangeability.
Regulatory / method suitability checks
Time-point designAt least three non-zero time points are commonly required for f₂; use the same pre-specified time points for both products.
Unit countCommon guidance expects at least 12 individual dosage units for each product at each time point.
VariabilityFor mean-data f₂ use, common criteria are CV/RSD below 20% at the earliest point and below 10% at later points (confirm the applicable guideline).
85% ruleCommon guidance limits the calculation to no more than one mean time point above 85% dissolved for either profile. Sampling points used should follow the relevant guideline and pre-specified protocol.
Rapid dissolutionFor some immediate-release oral products, >85% dissolved within 15 minutes may allow similarity to be accepted without f₂. Applicability is product- and guideline-specific.
Modified-release productsUse product-specific guidance and an appropriate sampling schedule; do not automatically apply immediate-release criteria.
Important: This calculator flags common conditions but does not replace a protocol, validated software, pharmacopoeial method, regulatory guidance, or expert review. The user selects which pre-specified time points are included in the calculation.
Reference guidance
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Formulation