The Rainbow Dynamic Dissolution Monitor (RDDM®) is a powerful analytical instrument that accurately and efficiently measures percent dissolved data in real time.  


Frustrated by the limitations of manual or semi-automated sampling? 

Overwhelmed by the demands put on your dissolution lab? 

Desperate for more detail in your dissolution profiles?


Pion’s fiber optic-based RDDM, celebrating its 20th year anniversary, is used throughout the industry and serves as the benchmark for in situ dissolution monitoring.  Whether USP dissolution or more novel apparatus are your area of research, in situ analysis can

                • improve throughput
                • reduce consumables
                • eliminate waste streams
                • provide more detailed profiles


Built with a world-class optical bench, the RDDM allows for the simultaneous analysis of up to 8 vessels as fast as every 2 seconds. No more offline LC analysis. No more dealing with pump maintenance and troubleshooting. The fastest path to accurate dissolution analysis is the focus of the technology. 


Pump the light.  Not the liquid.








The Rainbow™ can be used for anything that traditional UV monitoring solutions can be used for. Applications include:


  • Small volume dissolution – tablets and powder
  • Excipient screening
  • Nanoparticle dissolution
  • Salt screening
  • Intrisic dissolution
  • Media pH change
  • Stability monitoring
  • Supersaturation studies
  • Solubility – Aqueous and Non-Aqueous
  • Biorelevant dissolution media
  • Rank order intrinsic dissolution
  • Detect polymorphic changes
  • Follow stability profiles
  • Track supersaturation effects
  • Determine equilibrium solubility
  • USP and EU dissolution
  • Microsuspension
  • Dynamic media change
  • And more


If you have any questions about other fiber optic applications, Contact Us.





  • Up to 8 channels with dedicated PDA for each channel
  • 200-720 nm effective range
  • Scanning frequency as fast as every 2 seconds
  • Linear range up to 1.6+ A.U.
  • Durable stainless steel dip probes with variable path lengths of 1, 2, 5, 10 or 20 mm.
  • Horizontal analysis path available through the J style dip probe



Additional Resources