The MicroDiss Profiler is an innovative in-situ online fiber optic concentration detection system with 8 sample positions and a software-manipulable mini-workstation specifically designed for real-time determination of insoluble drug concentrations in small volumes (1-20mL). It can be used for pre-prescription determination of supersaturated solubility of solid dispersions, nanoparticle solubility, intrinsic dissolution rates, two-step dissolution experiments, osmotic absorption fluxes, and other concentration measurements requiring high accuracy and reproducibility. Only a few hundred micrograms of sample are required for a single experiment. The system can be configured with up to 8 channels of fiber optic, 200-720nm full spectrum data acquisition, the fastest acquisition frequency of 2 seconds / times for concentration detection.