Dissolution is one of the first methods applied in formulation development to gain information on the expected in-vivo performance of the pharmaceuticals. Nanoparticle development process suffers currently from the limited capability of dissolution methods especially on the separation of nanoparticles from the dissolution media for the quantification of dissolved drug. Conventional methods such as filtration, centrifugation, dialysis membrane have all different limitations in separation of nanoparticles from dissolution media where none of these methods can supply sufficient information on the in-vivo performance of nanoparticle formulations. This information is of crucial importance for the scientists developing nanoparticle formulations to be able to select the lead formulations with the best expected in-vivo profile. In this presentation the drawbacks of current dissolution methods for nanoparticles are described together with proposals for the improvement of the performance of dissolution methods for nanoparticles introducing an online sytem for the separation of the nanoparticles from dissolution media.