No, the similarity factor (F2) is a mathematical representation of the quadratic mean difference between two dissolution profiles across all considered time points. An F2 value of 50 indicates that the two profiles differ by a small margin, with a mean difference of approximately 10%.
The similarity factor is not a linear indicator:
- An F2 value of 100 represents a 0% mean difference.
- An F2 value of 50 corresponds to about a 10% mean difference.
- However, an F2 value of 75 does not correspond to a 5% mean difference. Instead, it indicates a mean difference of approximately 3%.
The F2 equation is specifically designed to be more sensitive to differences when those differences are below 10% for better discrimination.
Simply instead of F2 equation, the Quadratic mean of the difference in %dissolved over the considered time point may be calculated and the two profile considered similar if the results is less than 9.95.
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Resource Person: Abd El-Rahman Sayed