Bioequivalence and Bioavailability Forum

Dear All,

I would like to know your opinion about this issue: In my country (Brazil), it has authorized the market of metformin 500mg modified release (glifage XR 500mg. So, I would like to design a study to application of a new formulation: metformin 1000mg modified release (MR). The brazilian guidance about new dosages and formulations (RDC 136/03) is so confused. So, my question is:

Is the most adequate study (relative bioavailability) a study 2x2 comparing 1000mg MR versus 2 x 500mg MR (single dose) or a study 2x2 comparing 1000mg MR (single dose) versus 500mg - immediate release taken at time 0h and 12h (with sample colletions until 24h)?

I would like to know international regulations about this topic too.

Any comments about this topic will be very important to me.

Regards,

Daniel Rossi de Campos