## FDA-Subject by formulation interaction (Switchability) [Regulatives / Guidelines]

» Now, as we are doing a fully replicate study as suggested by OGD recommendation on methyl­phenidate, can we use RSABE approach in case if we get ISCV-reference > 30% for any one of the PK parameter Cmax or partial AUCs, instead of using 90% CI calculation to prove the bio­equivalence?

Yes. Reason is that it is possible for one of those PK parameters to show ISCV > 30%.
As an added bonus, even if a BE guidance states that crossover studies are required but you have data to support that the drug of interest is HVD (ISCV>30%, provided that the high ISCV is not because your formulation is crap) then you can run the studies as replicates. I have done 2 projects in the past already.

P.S. You woke me up from my hibernation Helmut...

John