PK parameters from multiple doses [PK / PD]

posted by Helmut Homepage – Vienna, Austria, 2017-11-19 11:24 (1958 d 18:01 ago) – Posting: # 17991
Views: 8,603

Hi Jeewaka,

❝ […] a PK study where multiple doses are given […] to estimate the PK parameters of the single dose from the blood concentrations of multiple dosing.

❝ is this possible?

Not easy. You could only perform modeling assuming (!) linear PK (clearance will not change over time). Given your sampling schedule I guess it will be very difficult to model anything beyond a simple one compartment model (e.g., ≥2, Michaelis-Menten elimination, circadian rhythms influencing the PK after the morning/evening doses, saturation of metabolising enzymes after accumulation, auto-induction or inhibition …). Even then you get only PK parameters describing the overall behaviour of the drug – not “of the single dose”. See this example of auto-induction (slides 21–22). With your sampling schedule I guess it would be impossible.* Next time I strongly suggest to sample at the pre-doses to get an idea. Much better to sample after the first dose as well.

   The combination of some data and an aching desire
for an answer does not ensure that a reasonable answer
can be extracted from a given body of data.
    John W. Tukey

Dif-tor heh smusma 🖖🏼 Довге життя Україна! [image]
Helmut Schütz

The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes

Complete thread:

UA Flag
 Admin contact
22,559 posts in 4,725 threads, 1,607 registered users;
13 visitors (0 registered, 13 guests [including 6 identified bots]).
Forum time: 06:25 CEST (Europe/Vienna)

The penalty for scientific irrelevance is, of course,
that the statistician’s work is ignored by the scientific community.    George E.P. Box

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz