Bioequivalence and Bioavailability Forum

Formulas… [Study As­sess­ment]

posted by Shuanghe  – Spain, 2025-11-05 15:24 (231 d 20:07 ago) – Posting: # 24479
Views: 2,832

Hi Helmut,

❝ diving into the formulas. Ugly as shit in the ICH M9 guideline$$\text{f2}=50\phantom{.}\tiny{\bullet}\normalsize\phantom{.}\log\{\text{[}1+(1/\text{n}){\Sigma_{\text{t=1}}}^\text{n}(\text{R}_\text{t}-\text{T}_\text{t})^2\text{]}^{-0.5}\phantom{.}\tiny{\bullet}\normalsize\phantom{.}100\}\tag{1}$$

This reminds me the formular in FDA's 1995 guidance of SUPAC for IR formulation where the f2 formula appeared the very first time in the regulatory guideline. Ugly indeed.

❝ IMHO, if you have the average difference, you should not square it. You need the average of squared difference.

You're right. My excuse is that I posted it right before I went to Switzerland for 3-day weekend (!) so I wasn't really in the thinking mode

Complete thread:

• Comparing two plasma concentration profiles Darborn 2025-10-17 05:40 
  • Comparing two plasma concentration profiles Helmut 2025-10-17 12:51
    • Comparing two plasma concentration profiles Darborn 2025-10-21 01:02
      • Comparing two plasma concentration profiles ElMaestro 2025-10-21 12:39
    • Comparing two plasma concentration profiles Shuanghe 2025-10-29 16:27
      • MathJax Helmut 2025-10-29 17:01
      • Formulas… Helmut 2025-10-30 10:28
        • Formulas…Shuanghe 2025-11-05 14:24
  • Negative ƒ2 is possible Helmut 2025-10-30 15:40
    • Interesting, however... ElMaestro 2025-11-03 14:15
    • Negative ƒ2 is possible Darborn 2025-11-07 06:04