## Cτ by lin-/lin, lin-up/log-down, and λz [NCA / SHAM]

❝ ❝ By the linear trapezoidal method (dammit!)…

❝ For some reason (may be for it's simplicity) russians like linear method and include it into the protocols.

Simplicity or simple minds? SCNR. Following textbooks of the 70s of the last century? No pocket calculators? Even in f**ing Excel one can implement the lin-up/log-down.

❝ I recalculated via lin-up/log-down and now I'm puzzled with a new question: why do C_{τ}'s differ by the way of calculation AUC? For linear I've got 3,38...

Gotcha! By specifying the linear trapezoidal you tell PHX that you

*believe*that the drug between time points is eliminated in zero (!) order like водка. You get what you want for t=24, namely by

*linear*interpolation (24–18)(2–20)/(24.5–18)+20=3.385. ∎

❝ (by the way, what are (1) and (2) on your presentation, slide 18?)

Values obtained by formulas (1) and (2) of slide 16.

Note that in interpolation PHX doesn’t use the estimated λ

_{z}(6–24.5: 0.2103) but the local slope (18–24.5: 0.3542).

❝ Is it correct to use t_{0} and t_{1}, if dosing time happened between this two points? I mean for the time before dose (t_{0}), the curve should be decreasing exponentially, while for the t_{1} it should be rising similar to linear?

Good point. Unfortunately we don’t know the elimination of the previous dose.

❝ ❝ […] Don’t you have any accumulation or is the method lousy?

❝ I was lucky enough not to get it till now but shit happens, you know, and a danger foreseen is half avoided. Is it a bad idea to miss that BLQ for ss elimination part?

Maybe, maybe not. Depends on your sampling schedule and how much the previous concentration is >LLOQ.

❝ What is about regulatory's acceptance of any of the calculation modifications? I may use profound methods of numeric integration, but would it be accepted?

Duno. I always describe

*exactly*what I plan to do in the protocol. Never got any questions afterwards. Believe me, I would make the life of an assessor miserable if at the end he/she doesn’t buy sumfink which was approved by his/her own agency and the ethics committee before.

*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

### Complete thread:

- AUC0-tau at steady state BNR 2016-03-31 22:46 [NCA / SHAM]
- AUC0-tau at steady state jag009 2016-03-31 23:05
- AUC0-tau at steady state BNR 2016-03-31 23:43
- RTFM Helmut 2016-04-01 00:59
- RTFM BNR 2016-04-01 02:05
- AUC0-τ estimation with time deviations Astea 2019-02-10 16:38
- AUC0-τ estimation with time deviations Helmut 2019-02-10 19:32
- Cτ for lin and lin-up/log-down Astea 2019-02-10 20:50
- Cτ by lin-/lin, lin-up/log-down, and λzHelmut 2019-02-11 01:45
- inter- vs extra- Astea 2019-02-11 19:46
- inter- vs extra- Helmut 2019-02-12 02:20
- No rule fits all mittyri 2019-02-14 12:55
- one size fits all vs goal posts Astea 2019-02-16 08:33
- one size fits all vs goal posts ElMaestro 2019-02-16 13:33
- Bias etc. Helmut 2019-02-16 14:26

- software: NCA not validated Helmut 2019-02-16 13:59
- no way out for NCA validation? mittyri 2019-02-20 21:22

- Default rules mittyri 2019-02-20 21:40

- one size fits all vs goal posts ElMaestro 2019-02-16 13:33

- one size fits all vs goal posts Astea 2019-02-16 08:33

- inter- vs extra- Astea 2019-02-11 19:46

- Cτ by lin-/lin, lin-up/log-down, and λzHelmut 2019-02-11 01:45

- Cτ for lin and lin-up/log-down Astea 2019-02-10 20:50

- AUC0-τ estimation with time deviations Helmut 2019-02-10 19:32

- RTFM Helmut 2016-04-01 00:59

- AUC0-tau at steady state BNR 2016-03-31 23:43

- AUC0-tau at steady state jag009 2016-03-31 23:05