Bioequivalence and Bioavailability Forum

Dear Rocky
for a reasonable reply I would need some further information. First why did you think, that a bio study was not required? A BCS class I or III biowaiver does not apply (non-linearity, variable absorption).
According to CPMP/QWP/EWP/1401/98 Rev. 1 bioequivalence should in most cases be established both at the highest strength and at the lowest strength for drugs with a less than proportional increase in AUC with increasing dose over the therapeutic dose range. However you have the problem, that for the lowest strength you have no reference product. Testing of 2.5mg x 4 vs 10mg x 1 would be of no help if the non-linearity is not caused by limited solubility but is due to e.g. saturation of uptake transporters. A line extension (additional strength) would only be possible within the therapeutic dose range (strengths) covered by the originator. For additional strengths outside the originatorś dose range you need to submit clinical data.
BTW what does RMP & ERP mean?
Kind regards
Dan