Bioequivalence and Bioavailability Forum

Dear all,

I have a question about conducting comparative bioavailability study between the active metabolite produced following an oral dose of the parent drug and a new formulation containing only that active metabolite

If the parent drug is converted to metabolite (A) and we want to compare the relative bioavailability of compound (A) to a new formulation containing the active metabolite.



So, The Reference product would be the active metabolite produced following oral dose of parent drug and the test product will be the new formulation containing only the active metabolite.

If the two products shows similar rate and extent of absorption, can we conclude BE using TOST and claim that the new formula can be substituted for the parent drugs since it produces similar pk profile based on metabolite data ?

The metabolite has longer t1/2.
No registered drug containing only the active metabolite.
The drug product is Chloral hydrate and its trichloroethanol as active metabolite.

Relative BA of CH and its active metabolite

Thanks in advance.