Bioequivalence and Bioavailability Forum

Dear MGR!

❝ I had a doubt regarding the truncation of sampling points in suspension-injections like Methylprednisolone Inj. Susp, Triamcinolone Inj. Susp, etc.

Truncated AUC generally may be applied to drugs exhibiting long elimination half-lives only. The definition of 'long' varies between guidelines, but 24 hours is a rule of thumb.
Both of your example drugs do not belong to this category.

❝ In these type of suspension-injections studies can we do the truncation method? Is it acceptable by the regulatory bodies?

I don't have personal experiences with your formulations, but if a slow release causes an apparent long half life, you are actually seeing the absorption phase (in PK the slowest process comes up as the 'terminal' one). Since in BE we are interested in differences between formulations, close monitoring of the absorption phase is a must. Therefore I do not think that any regulator will accept truncation in these cases.