Dissolution f2 similarity calculator
The same similarity-factor computation our dossier simulation gates run. Paste a reference profile and a test profile - percent dissolved at each time point - and get the f2 value, the similarity verdict, and which official decision rules fired. Everything computes in your browser; nothing is sent anywhere.
The calculator / FDA & EMA model-independent approach
The math / and the rules that decide the verdict
The similarity factor is a logarithmic transform of the mean squared difference between the two profiles:
where Rt and Tt are mean % dissolved for reference and test at time t, and n is the number of time points. f2 ranges 0-100; f2 ≥ 50 is the regulatory similarity threshold - two profiles with f2 ≥ 50 differ by no more than ~10% on average.
This tool applies the decision rules regulators apply:
- Minimum points: at least 3 time points (zero excluded) are required for a valid f2.
- 85% rule: only one time point may be used after both profiles have reached 85% dissolved - later points are dropped from the computation.
- Mean profiles: enter means across vessels (n ≥ 12 units recommended by FDA; ≥ 6 by some authorities).
- Variability: official guidance also caps within-profile variability (CV ≤ 20% early points, ≤ 10% later) - assess that against your raw vessel data; this calculator works on means.
When f2 < 50 or the rules cannot be met, similarity is not established and regulators expect either multivariate/model-dependent methods or in-vivo evidence - the same branch our simulation gates encode.
Why this is public / check our math
Lawsone's dossiers are licensed under NDA, but the methods are not secret - and they should not be taken on trust. This page runs the identical f2 gate our pipeline applies to every candidate formulation: paste any published reference profile and any candidate, and you reproduce the exact computation that decides pass or fail inside our dossier production line.
If you are diligencing a Lawsone dossier, every f2 table in it can be re-checked here, point for point.