BE-proff
●    

2015-11-02 15:24
(3069 d 02:27 ago)

Posting: # 15601
Views: 8,482
 

 Why do we need AUMC? [PK / PD]

Hi All,

I do understand that I am asking stupidity but I can't catch the idea why AUMC is required? :confused:
Can anybody explain me? :-)
mittyri
★★  

Russia,
2015-11-02 15:44
(3069 d 02:07 ago)

@ BE-proff
Posting: # 15603
Views: 7,153
 

 Why do we need AUMC?

Hi BE-proff,

❝ I do understand that I am asking stupidity but I can't catch the idea why AUMC is required?


I think good explanation you can find here and here.

AFAIK it is just a way to calculate MRT.
BTW may be PK Guru can clarify it more precisely ;-)

Kind regards,
Mittyri
d_labes
★★★

Berlin, Germany,
2015-11-02 15:55
(3069 d 01:56 ago)

@ mittyri
Posting: # 15605
Views: 7,246
 

 Do we need MRT?

Dear mittyri,

❝ AFAIK it is just a way to calculate MRT.


IMHO totally correct.
On the other hand, if I see it correctly, there is no need for MRT. At least in Europe.

Regards,

Detlew
Helmut
★★★
avatar
Homepage
Vienna, Austria,
2015-11-02 16:13
(3069 d 01:38 ago)

@ BE-proff
Posting: # 15606
Views: 7,543
 

 AUMC ⇒ MRT

BE-proff,

❝ […] I can't catch the idea why AUMC is required? :confused:


In the BE-context you generally don’t need it at all. It’s only an intermediate step in calculating MRT. Who asked for it?

❝ Can anybody explain me? :-)


We can see plasma profiles as the result of a stochastic process (drug molecules are absorbed, distributed, and metabolized/excreted). At any given time point a certain fraction is in the cir­cu­la­tion. Hey, that’s a sta­tis­tical distribution!

Distributions can be described by ‘statistical moments’

\(S_0=\int f(x)dx\)
\(S_1=\int x\cdot f(x)dx\)
\(S_2=\int x^2\cdot f(x)dx\)

where \(\small{S_0}\) is the AUC and \(\small{S_1}\) the AUMC (Area Under the Moment Curve). In PK \(\small{x=t}\) and \(\small{f(x)=C}\). We need the AUMC to calculate the MRT (Mean of Residence Times), which is for
  • iv bolus
        MRT = AUMC / AUC
  • and for infusion (of length tinf)
        MRT = AUMC / AUC – ½tinf
Rule of thumb: After MRT ~⅔ of the drug is eliminated.

S2 is rarely used (for the calculation of the ‘Variance of Residence Times’): VRT = S2/S0 – (S1/S0)2. MRT and VRT are the coordinates (x|y) of the ‘center of gravity’ of the profile. Try it: Plot a PK-curve on cardboard and stick a pin through x|y. Makes a nice children’s wind wheel.

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BE-proff
●    

2015-11-02 20:18
(3068 d 21:33 ago)

@ Helmut
Posting: # 15607
Views: 7,040
 

 AUMC ⇒ MRT

Dear Helmut,

Thanks a lot for your clarification! :ok:
Actually AUMC is not required by Russian authorities.
This parameter is computed by Bear and as I could't find any clear explanation for it I decided to post this question.

Not bad for self-education;-)
yjlee168
★★★
avatar
Homepage
Kaohsiung, Taiwan,
2015-11-02 20:43
(3068 d 21:08 ago)

@ BE-proff
Posting: # 15608
Views: 7,038
 

 AUMC ⇒ MRT

Hi BE-proff,

❝ ... Actually AUMC is not required by Russian authorities.


Both AUMC and MRT are not the pivotal parameters for bioequivalence study for all areas or countries. They are just parts of NCA.

❝ This parameter is computed by Bear..


Yes, bear computes both.

All the best,
-- Yung-jin Lee
bear v2.9.1:- created by Hsin-ya Lee & Yung-jin Lee
Kaohsiung, Taiwan https://www.pkpd168.com/bear
Download link (updated) -> here
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