Bioequivalence and Bioavailability Forum • Parameter-identifiability?

Parameter-identifiability? [PK / PD]

posted by Helmut – Vienna, Austria, 2019-09-07 15:03 (2078 d 13:07 ago) – Posting: # 20552
Views: 5,461

Hi mittyri,

❝ […] data from MD study for IR formulation […] another dataset (SD) […] but MR formulation. Trying to build the model you figure out that the parameters differ significantly (both Cl and V).

❝ What could be a reason of that observation?

Flip-flop PK? Rather the rule than an exception with MR formulations. You might run into parameter-identifiability issues. Unless you have data from an IV dose you don’t know what the true elimination is.
An idea: Parameterize models with rate-constants (instead of CL) and compare k_el of the IR formulation with k_a of the MR formulation. Are they similar?

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Helmut Schütz

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Complete thread:

PK model parameters IR vs MR mittyri 2019-09-02 22:15 [PK / PD]
- PK model parameters IR vs MR jag009 2019-09-03 16:07
  - PK model parameters IR vs MR mittyri 2019-09-03 16:54
- PK model parameters IR vs MR ElMaestro 2019-09-03 17:43
  - PK model parameters IR vs MR mittyri 2019-09-03 18:05
- Parameter-identifiability?Helmut 2019-09-07 13:03
  - transit compartments... mittyri 2019-09-07 22:25
    - No organs in (Pop)PK Helmut 2019-09-08 10:56