Bioequivalence and Bioavailability Forum

Hi Dshah,

of course, all what you wrote is correct. I performed studies for an originator (new formulation), where t≥MIC* was the only confirmatory PK metric (see also this post). Studies accepted.

However, we must not forget one important point: The MIC is based on in vitro data. Generally we have more than one MIC (dependent on the bacteria / strain). Everybody (myself included) compared the in vivo concentrations of the PK study with the in vitro MIC. That’s not the same thing… Is there a 1:1 relationship? I strongly doubt it.
Can/should we really do that? Well, cough… 

BTW, we have a similar mix-up of PK with PD in the so-called “Therapeutic Occupancy Time” based on the misconception that C_max is directly (‼) related to safety (toxicity) and C_min to a potential lack of efficacy. See also this post.

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• t≥MIC, if you don’t mind. T is the SI abbreviation for the absolute temperature and t for time. Hence, t_max, t_min, t_lag, t_½ as well. Forget what you find in the FDA’s guidances.