Bioequivalence and Bioavailability Forum • Washout based on mean ± SD of t½

Washout based on mean ± SD of t½ [Design Issues]

posted by Helmut – Vienna, Austria, 2022-09-26 19:35 (847 d 21:25 ago) – Posting: # 23322
Views: 4,116

Hi Imph,

❝ I would like to know if this method can be applied to each pharmacokinetic measurement, for example to determine the duration of the sampling (5 x t1/2) or to calculate the predose limit of 5% Cmax when the Cmax is provided in the literature under mean+/-SD.

In principle, yes. I prefer to start with a single dose profile (even if read from a published figure) and perform nonparametric superposition.

❝ Why plan for 95% coverage (z0.95 = 1.96), is it related to alpha =5%.

Convention. You can use a more conservative value.

❝ In the reference you gave, a normal distribution is assumed, but pharmacokinetic measurements do not generally follow a normal distribution but a log-normal one. Does this method still apply?

You are right. But if the arithmetic mean ± SD is all you have… If you have results for the geometric mean, better, of course.

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Complete thread:

Washout based on mean ± SD of t½ Imph 2022-09-25 13:52 [Design Issues]
- Washout based on mean ± SD of t½ Helmut 2022-09-25 16:08
  - Washout based on mean ± SD of t½ Imph 2022-09-26 15:24
    - Washout based on mean ± SD of t½ Shuanghe 2022-09-26 17:34
    - Washout based on mean ± SD of t½Helmut 2022-09-26 17:35
    - If you have data… Helmut 2022-09-27 11:52
      - If you have data… Imph 2022-10-25 09:21
  - Washout based on mean ± SD of t½ Imph 2023-05-26 23:31
    - Washout based on mean ± SD of t½ Helmut 2023-05-27 06:52
      - Washout based on mean ± SD of t½ Imph 2023-05-27 08:36