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Researcher101 ☆ Egypt, 2020-10-14 12:21 (1655 d 07:30 ago) Posting: # 21997 Views: 4,088 |
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Dears, I just wanna know if Steadystate Cmax intrasubject variability will be considered in sample size calculations of multiple dose BE? or just Cmax of single dose? Also is it in the safe side to estimate sample size based on Cmax single dose not multiple dose? Edit: Category changed; see also this post #1. [Helmut] |
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Helmut ★★★   Vienna, Austria, 2020-10-14 13:27 (1655 d 06:23 ago) @ Researcher101 Posting: # 21999 Views: 3,479 |
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Hi Researcher101, if you have the CV of Cmax from a MD study that’s best, of course. ❝ Also is it in the safe side to estimate sample size based on Cmax single dose not multiple dose? Yes, since generally (I know only one published exception*) variability in steady state is ≤ the one after a single dose.
— Dif-tor heh smusma 🖖🏼 Довге життя Україна! ![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png) Helmut Schütz ![[image]](https://static.bebac.at/img/CC by.png) The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes |
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Researcher101 ☆ Egypt, 2020-10-14 15:37 (1655 d 04:13 ago) (edited on 2020-10-19 10:41) @ Researcher101 Posting: # 22000 Views: 3,404 |
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Also if Cmax ss within variability is around 20 % and Cmin ss within variability is around 41 % on which one should I depend Dears, I am asking about the factor we determine the sample size in multiple dose studies? Should I estimate sample size based on intra subject variability of Cmin or Cmax or C tau? Can I pool the CVs to estimate sample size? Edit: Full quote removed. Please delete everything from the text of the original poster which is not necessary in understanding your answer; see also this post #5! [Ohlbe] Edit: Post merged with a new (deleted) post of 2020-10-19. Relax; see also this post #9. [Helmut] |
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Helmut ★★★ Vienna, Austria, 2020-10-19 18:17 (1650 d 01:33 ago) @ Researcher101 Posting: # 22030 Views: 3,369 |
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Hi Researcher101, ❝ […] sample size in multiple dose studies? Should I estimate sample size based on intra subject variability of Cmin or Cmax or C tau? Based on the one with highest variability – if the assumed T/R-ratios are identical. If not, explore various combinations and opt for the worst case. This gives you a safety margin for the other PK metrics. ❝ Can I pool the CVs to estimate sample size? Doesn’t make any sense. — Dif-tor heh smusma 🖖🏼 Довге життя Україна! Helmut Schütz The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes |
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dshah ★★ India, 2020-10-20 08:43 (1649 d 11:08 ago) @ Researcher101 Posting: # 22033 Views: 3,221 |
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Dear Researcher 101, If you have performed any single dose study, its best to perform Superposition as per SmPC/ PI instruction. Then perform the stat at Steady state- you will know the %CV for all the required parameter and then take a call. Mostly- based on theoretical assumption, the %CV will come less in multi dose for this phenomena. Regards, DShah |
Ing. Helmut Schütz