## Fantastic PK parameters and where to find them [NCA / SHAM]

Hi Astea

» While reading the forum I sometimes face to the statements that other PK parameters should be used in future researches for SD studies. Below is my collection of stange or rare parameters. I would be grateful if you'll comment on their properties, details of calculation and the perspectives of its using.

I think F may be in its own right also included on your list of crackpot ideas from the odd sock drawer? PMDA have a sentence about it in their guidance. "If F can be calculated by deconvolution, F may be used instead of AUC"

» The distribution type of the function is also questionable (ratio of log-normal - paranormal ?).

Paranormal is exactly what it is.

Conveniently, ln(A)-ln(B)=ln(A/B). If A is normal and B is normal then their sum (difference) is normal, and it is trivial to work mean and variance out. But the ratio of two normal distributions is distinctly not normal. We can't just say the ratio of two log-normals is normal (or log-normal, depending on the level of liguistic nitpicking); we need to keep in mind on which scale we subtract or add, and on which scale we do the ratio.

Kindly send me a telegram when someone works out the distribution of the ratio of two normals

» While reading the forum I sometimes face to the statements that other PK parameters should be used in future researches for SD studies. Below is my collection of stange or rare parameters. I would be grateful if you'll comment on their properties, details of calculation and the perspectives of its using.

I think F may be in its own right also included on your list of crackpot ideas from the odd sock drawer? PMDA have a sentence about it in their guidance. "If F can be calculated by deconvolution, F may be used instead of AUC"

» The distribution type of the function is also questionable (ratio of log-normal - paranormal ?).

Paranormal is exactly what it is.

Conveniently, ln(A)-ln(B)=ln(A/B). If A is normal and B is normal then their sum (difference) is normal, and it is trivial to work mean and variance out. But the ratio of two normal distributions is distinctly not normal. We can't just say the ratio of two log-normals is normal (or log-normal, depending on the level of liguistic nitpicking); we need to keep in mind on which scale we subtract or add, and on which scale we do the ratio.

Kindly send me a telegram when someone works out the distribution of the ratio of two normals

—

I could be wrong, but...

Best regards,

ElMaestro

"Pass or fail" (D. Potvin et al., 2008)

I could be wrong, but...

Best regards,

ElMaestro

"Pass or fail" (D. Potvin et al., 2008)

### Complete thread:

- Fantastic PK parameters and where to find them Astea 2020-06-12 14:22 [NCA / SHAM]
- Fantastic post 👍🏽 Helmut 2020-06-12 16:23
- Rattleback Astea 2020-06-13 10:17
- Chatter Helmut 2020-06-13 12:28
- Reinventing the Hula-Hoop Astea 2020-06-16 01:33
- Hula-Hoop references Helmut 2020-06-16 13:07
- Prof. Keller vs. Yamaoka mittyri 2020-06-17 14:28
- SHAM(e) math Astea 2020-06-23 14:41
- SHAM(e) math Helmut 2020-06-23 15:55
- OT: Möbius strip Astea 2020-06-23 21:41
- OT: Möbius strip Helmut 2020-06-24 11:29

- OT: Möbius strip Astea 2020-06-23 21:41

- SHAM(e) math Helmut 2020-06-23 15:55

- SHAM(e) math Astea 2020-06-23 14:41

- Prof. Keller vs. Yamaoka mittyri 2020-06-17 14:28

- Hula-Hoop references Helmut 2020-06-16 13:07

- Reinventing the Hula-Hoop Astea 2020-06-16 01:33

- Chatter Helmut 2020-06-13 12:28

- Rattleback Astea 2020-06-13 10:17
- More stuff Helmut 2020-06-13 15:28
- MRT and Gravity duration mittyri 2020-06-14 22:24
- Fantastic PK parameters and where to find themElMaestro 2020-06-16 09:46
- Cauchy distribution mittyri 2020-06-16 10:54
- Cauchy distribution Helmut 2020-06-16 13:14
- Cauchy distribution ElMaestro 2020-06-20 10:33
- noncentral normal ratio mittyri 2020-06-20 23:04

- Cauchy distribution mittyri 2020-06-16 10:54

- Fantastic post 👍🏽 Helmut 2020-06-12 16:23