I will be doing an invitro study on lipase inhibition of an extract vs. orlistat using IC50. I will be using different concentrations of the extract to identify the concentration that is comparable or at higher potency than orlistat.
This will be followed by an invivo study in rats using the extract vs. orlistat. Can I apply that identified concentration of extract to my invivo experiment so I can expect the results of the extract group to be comparable or even greater than the orlistat group?
Thank you.
Hi there,
This is a very difficult issue as many more parameters are implicated in in vivo experiment compared to in vitro : biodisponibility of the molecule, accessibility to the target protein, level of targeted enzyme activity, availability of substrate, aso.
I agree with Dominique Liger. As an example, suppose you use in vivo an amount of the extract that produces the same degree of enzyme inhibition as orlistat in the in vitro assay, but the active ingredient in the extract is cleared much faster from the circulation than orlistat. The effect of the extract will likely be less than orlistat in such a case (all else being equal) because the exposure of the enzyme in vivo to the extract's active ingredient will be reduced compared to orlistat.
Thank you. I guess, I have two options: to remove orlistat as a positive control in my mice experiment. OR, retain the orlistat group but to add another group with larger dose of the extract. What do you think?
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