Bioequivalence and Bioavailability Forum • Circadian rhythm?

Circadian rhythm? [Design Issues]

posted by Helmut – Vienna, Austria, 2024-01-20 13:50 (528 d 12:19 ago) – Posting: # 23834
Views: 3,714

Hi NK,

❝ We are planning a steady state bioequivalence study on healthy subject with tid dosing (every 8 hours) on day 1 to day 4. Serial PK blood sample collections are planned on Day 5 after morning dosing(expected to reach steady state concentration on day 5).

❝ Kindly clarify, whether 2nd and 3rd dose on day 5 need to be administered or not? and sampling should be continued for 24 hours?

If you have evidence from peer-reviewed literature that the PK of the drug is not subjected to a circadian rhythm, the profile after the first dose in steady state is sufficient. Otherwise, you have to dose also tid on day 5 and the primary PK metric for the extent of absorption will be AUC_ss,0–24h. A ‘classical’ example is theophylline.

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Complete thread:

Steady state BE study dosing NK 2024-01-19 04:24 [Design Issues]
- Circadian rhythm?Helmut 2024-01-20 12:50
- Steady state BE study dosing dshah 2024-01-22 10:09
  - AUC in steady state Helmut 2024-01-27 22:01
    - AUC in steady state dshah 2024-01-27 22:06
      - AUC in steady state Helmut 2024-01-27 22:16