Parameter-identifiability? [PK / PD]

posted by Helmut Homepage – Vienna, Austria, 2019-09-07 13:03 (538 d 10:24 ago) – Posting: # 20552
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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 kel of the IR formulation with ka of the MR formulation. Are they similar?

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