Table VIII.
Recommended f 2 Harmonized Criteria
| Parameter | Recommended criteria |
|---|---|
| Number of units for test and reference | 12 unless otherwise justified |
| f 2 value to claim similarity | 50–100 (14) |
| Criteria for f 2 exemption | Where more than 85% of the drug is dissolved for both test and reference products within 15 min, dissolution profiles may be accepted as similar without further mathematical evaluation. (5,14,17,19,20,25–29) |
| Early time points | For immediate-release products, early time points are those that are less than or equal to 15 min. For modified-release products, early time points should be based on the shape of the profile (e.g., on the mean dissolution results). |
| Number of time points | At least five sampling time points must be selected to characterize the dissolution profiles. Only two points should be on the plateau of the curve and the other three should be distributed between the ascending and inflection portions of the profiles (25). |
| Last time point/measurement to include in an f 2 analysis | For both test and reference drugs, no more than one mean value >85% dissolved (14,18,26,28) |
| Coefficient of variation criteria | The percent coefficient of variation at the earlier time points should not be more than 20%, and at other time points should not be more than 10% (14,18,19,28) |