During the OrBiTo project, our knowledge on the gastrointestinal environment has improved substantially and biorelevant media composition have been refined. The aim of this study was to propose optimized biorelevant testing conditions for modified release products, to evaluate the reproducibility of the optimized compendial apparatus III (USP apparatus III) and compendial apparatus IV (USP apparatus IV, open-loop mode) dissolution methods and to evaluate the usefulness of these methods to forecast the direction of food effects, if any, based on the results of two «ring» studies and by using two model modified release (MR) products, Ciproxin / Cipro XR and COREG CR. Six OrBiTo partners participated in each of the ring studies. All laboratories were provided with standard protocols, pure drug substance, and dose units. For the USP apparatus III, the dissolution methods applied to Ciproxin / Cipro XR, a monolithic MR product of an active pharmaceutical ingredient (API) with moderate aqueous solubility, were robust with low intra- and inter-laboratory data variability. Data from all partners were in line on a qualitative basis with food effect data in humans. For the USP apparatus IV, the dissolution methods applied to COREG CR, a multiparticulate, pH dependent, MR product of an API with low and pH dependent solubility led to high intra- and inter- laboratory data variability. Data from all partners were in line, on a qualitative basis, with the previously observed food effects in humans.