Bioequivalence and Bioavailability Forum • OT: keep TTT!

OT: keep TTT! [PK / PD]

posted by yjlee168 – Kaohsiung, Taiwan, 2013-07-23 01:42 (4297 d 10:13 ago) – Posting: # 11035
Views: 21,705

Dear Helmut,

❝ [...]

❝ Please no! Contrary to R²_adj TTT is based on PK-grounds. I would not call it model-dependent. OK, it is based on a one-compartment model but the estimation of λ_z is within the boundaries of NCA, IMHO. For multiple distribution / elimination phases it is the responsibility of the user to select the last loglinear phase visually.

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. I don't know if you put too much noise or not. 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). I guess it will work only if user knows which is the 'breakpoint.' One more question: what if the 'breakpoint' is just not one of scheduled sampling times?

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

Agree.

—
All the best,
-- Yung-jin Lee
bear v2.9.2:- created by Hsin-ya Lee & Yung-jin Lee
Kaohsiung, Taiwan https://www.pkpd168.com/bear
Download link (updated) -> here

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