Bioequivalence and Bioavailability Forum

Therapeutic Occupancy Time / MEC [🇷 for BE/BA]

posted by Helmut  – Vienna, Austria, 2008-06-30 18:45 (6144 d 18:09 ago) – Posting: # 1989
Views: 36,627

Dear Ace,

OK, now everything’s clear. I like the way you set the limits – I would have used brute force and removed the datapoints from the data.frame…

In case you need the reference – it’s only one paragraph and a figure:

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Occupancy time
  Where a therapeutic window exists, ‘Therapeutic Occupancy Time’¹, the time that the plasma concentration stays within the therapeutic range, becomes an important criterion. In steady-state, the percentage of time the drug concentrations lies within the therapeutic window is important. In the cited example, the drug lies within the therapeutic window for the subject population about 80% of the time (Fig. 4).

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The figure is a nice illustration of the interpolation/intersection.
It should be noted that there’s also an upper limit, which complicates things: two formulations may have identical occupancy times from differently shaped curves! If not only the MIC but also toxicity is an issue, I would not suggest using the Occupancy Time without a thorough inspection of individual profiles.

Another one, mixing up concentration (PK) with effect (PD) a little bit:²

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1. Skelly JP, Barr WH. Biopharmaceutic considerations in designing and evaluating novel drug delivery systems. Clin Res Pract Drug Reg Aff. 1985;3(4):501–39. doi:10.3109/10601338509051086.
   
   
2. Goodman & Gilman’s The Pharmacological Basis of Therapeutics. McGraw-Hill; 11^th ed. 2006. p.19.

—
Dif-tor heh smusma 🖖🏼 Довге життя Україна! 
Helmut Schütz


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Science Quotes

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