. 2011 Jun;72(3):95–108. doi: 10.1016/j.curtheres.2011.04.001

Table III.

Comparison of the dissolution profile of 2 azithromycin capsule formulations (n = 12, where n is the number of capsules tested of each formulation).

Time (min)	Mean % Release		Difference Factor (f₁)	Similarity Factor (f₂)
Time (min)	Test Formulation	Reference Formulation	Difference Factor (f₁)	Similarity Factor (f₂)
0	0	0	5.47	70.04
15	39	43
30	56.6	61
45	76	79

f₁ calculates the percent (%) difference between the 2 curves at each time point and is the measure of the relative error between the 2 curves; f₂ is a logarithmic reciprocal square root transformation of the sum of squared error and is the measure of the similarity in the percent (%) dissolution between the 2 curves.