Bioequivalence and Bioavailability Forum

Hi Relaxation,

❝ I am not sure I agree with the interpretation here:

❝

❝ ❝ One of the prerequisites in BE is that same molar doses of the active ingredient are administered. If the enantiomeric ratio* of the reference is 1:1, IMHO, you would have to administer twice the dose of the test and use a chiral method (assessing only the active enantiomer for BE).

❝

❝ I would focus here on the wording "active ingredient". […] If there is only one active enantiomer, I would guess the other one is simply an inactive ingredient.

Ariëns’ isomeric ballast.*

❝ So in conclusion, proposing 50 mg of the pure active enantiomer as a generic to a product containing 100 mg of the 1:1 racemate would work for me.

You are right and I stand corrected! I doubt that such a product falls in the definition of a generic. However, Christian is interested in a new FDC.

❝ Got involved in a discussion on dexibuprofen briefly, but there it is more complicated due to interconversion and still some discussion of a contribution of both enantiomers to efficacy.

IMHO, dexibuprofen products are – to a large extent – marketing gimmicks.

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• Ariëns EJ. Racemic therapeutics — ethical and regulatory aspects. Eur J Clin Pharmacol. 1991;41(2):89–93. doi:10.1007/BF00265897.