artifact? [PK / PD]

posted by Helmut Homepage – Vienna, Austria, 2017-03-17 14:09 (2568 d 20:53 ago) – Posting: # 17160
Views: 4,130

Hi javier,

❝ in the single dose pk study (with full pk sampling ) the half life was reported in 17 days, while in the multiple dose study (with sparse sampling) the half life was reported in 26 days, How could it be possible?


First of all I don’t think that half lives are normal distributed. Hence, I don’t like the reported arithmetic means. ;-) There were different number of patients enrolled in the cohorts. Therefore, you should use weighted means which are 22.0 days (single dose) and 26.1 days (multiple dose). Such a difference does not worry me. Furthermore, half lives in the SD study were obtained by NCA and in the MD study by a two-compartment PopPK model. Since there is substantial accumulation it might be possible that in the SD study the terminal phase was not completely “visible” – especially after low doses and NCA underestimated the true (i.e., higher) value.

❝ How would you calculate the steady state in this situation?


What do you mean by that?

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

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

Complete thread:

UA Flag
Activity
 Admin contact
22,957 posts in 4,819 threads, 1,636 registered users;
106 visitors (0 registered, 106 guests [including 7 identified bots]).
Forum time: 11:02 CET (Europe/Vienna)

With four parameters I can fit an elephant,
and with five I can make him wiggle his trunk.    John von Neumann

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz
HTML5