Bioequivalence and Bioavailability Forum • OT: EOD (here)

OT: EOD (here) [PK / PD]

posted by Helmut – Vienna, Austria, 2013-07-23 03:06 (4350 d 10:38 ago) – Posting: # 11036
Views: 22,027

Dear Yung-jin,

❝ OK. I plot your simulated data as semi-log scale (log(C) vs. time) to see if the 'breakpoint' (which is occurring at 9) is easy to figure out visually. It is not.

No? Profiles like that one are not uncommon. I think it should not be too difficult to ‘eyeball’ the breakpoint somewhere between 6 and 12.

❝ I don't know if you put too much noise or not.

That was just a little _one…

❝ If we can visually figure out the 'breakpoint' easily, then we probably can change current TTT algo as a semi-automatic way. That is to pick the last 3-4 data points first (automatically) and then to show plots to allow user to add more until reaching 'breakpoint' (manually).

You shouldn’t call it TTT any more.

❝ I guess it will work only if user knows which is the 'breakpoint.'

In the real world this will ~~never~~ rarely happen.

❝ One more question: what if the 'breakpoint' is just not one of scheduled sampling times?

Same procedure as in TTT: Select the next one in the sampling schedule.* In my example the BP is 7.73 → start estimation at 9.

❝ ❝ Anyhow, I’m not overly optimistic yet – especially if at least one of the following conditions applies: • Noisy data. [...]

❝ Agree.

I’m not sure whether noise will be our biggest problem. I would suggest to stop here (hijacking John’s thread) and continue at the new one.

From the paper: “If no sampling time point is available for the twofold of the observed t_max value due to the sampling design, the next later time point […] should be used.”

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Complete thread:

1 compartment model with lag time jag009 2013-07-17 15:58 [PK / PD]
- solve for k01? Helmut 2013-07-17 16:08
  - solve for k01? jag009 2013-07-17 16:19
    - solve for k01? ElMaestro 2013-07-17 17:09
    - no closed form Helmut 2013-07-17 23:01
- 1 compartment model with lag time yjlee168 2013-07-17 20:57
- Package-free solution ElMaestro 2013-07-17 21:53
  - Package-free solution yjlee168 2013-07-17 22:11
    - Package-free solution ElMaestro 2013-07-17 22:27
      - Package-free solution yjlee168 2013-07-17 22:42
  - Package-free solution ElMaestro 2013-07-17 23:21
    - A new R-King was born d_labes 2013-07-18 08:45
      - Brent ElMaestro 2013-07-18 09:07
      - A new R-King was born yjlee168 2013-07-18 10:21
        
        OT: TTT in bear Helmut 2013-07-18 20:28
        
        OT: TTT in bear yjlee168 2013-07-18 22:17
        
        OT: TTT subtleties d_labes 2013-07-19 09:47
        
        OT: TTT subtleties yjlee168 2013-07-20 19:44
        
        OT: beyond TTT? Helmut 2013-07-21 00:08
        
        OT: beyond TTT? yjlee168 2013-07-22 13:45
        
        OT: keep TTT! Helmut 2013-07-22 14:21
        
        OT: keep TTT! yjlee168 2013-07-22 23:42
        
        OT: EOD (here)Helmut 2013-07-23 01:06
    - Package-free solution yjlee168 2013-07-18 10:27
      - Thank you guys! jag009 2013-07-18 16:37
        
        Thank you guys! ElMaestro 2013-07-18 18:57
        
        Thank you guys! jag009 2013-07-19 20:40