DSR-M Dissolution Sampling Robot
Semi-Automated Dissolution Testing

Manual sampling from a dissolution test instrument is not only time consuming but also limits the reproducibility and is close to impossible if sustained release products have to be analysed over prolonged time periods. The Pharma Test DSR-M (Dissolution Sampling Robot) provides a neat solution to this automation procedure.

The DSR-M automated dissolution sampling robot is designed specifically for the sample transfer and sample processing from a 6 to 8 (DSR-M8) or a 12 to 13 (DSR-M13) vessel dissolution bath. This unique and versatile instrument allows collecting, dilution and/or processing samples over very short time intervals. It can also be used for dissolution medium replenishment to conform to USP/EP volume loss rules. For media replacement, the CAT-MRM module is used and eliminates the need for separate refilling tubing lines compared to conventional offline systems.

Up to twenty sampling cycles can be run automatically. The sample preparation station, Z-arm and needle, can be used to dispense into Septa sealed HPLC vials or dilute samples. Keeping the samples in sealed vials helps avoiding evaporation, especially if sustained release products are tested.

The DSR-M is the first such system to be equipped with high precision valve-free piston pumps. Each channel contains a miniaturized valve-free pump element which ensures reliable precision (<0.5%). and accurate sample delivery (<1%) for each working channel. No time consuming pump calibration is needed. The advanced design of the system means that it is always ready for operation and as the pump is already built-in the system saves a lot of bench space. The separate rinse pump is invaluable to keep the system clear of crystallizing material, especially when using buffered media.

The DSR-M is equipped with two collection racks. Each rack has the capacity to store up to ten sampling cycles. In case sample processing, such a dilution is enabled, the first rack is used for collecting and the second rack for sample processing. The innovative rack design makes it possible to use the same racks for standard open vials as well as for septa sealed HPLC vials. The DSR-M is contained in a clear view Plexiglas enclosure. After the sampling is completed the rack can easily be pulled out and removed to transport the samples for analysis.

In case additional filtration besides the sinter filters on the sampling probes is required, we offer the MFC-12 manual filter changer. With this filter changer it is possible to conveniently exchange a filter for up to 12 channels in the dissolution system. The MFC-12 is installed into the tubing system of the dissolution system and can quickly be opened using the two open and close handles. When the MFC-12 is opened, the filters are automatically disconnected and can be removed quickly. New filters can then be inserted and are automatically locked into the tubing connectors, when the MFC-12 is closed again.

Since these round filters can pass liquid only in one direction, a bypass is needed to use the MFC-12 in a DSR-M system with CAT-M piston pumps. For this we offer the DSR-MSV valve station in multiple models according the number of channels in the automated dissolution system.

All necessary sample handling information, such as dilution factor, sample transfer into empty septa closed vials is directly entered at the DSR-M using the integrated keypad. The programming is displayed clearly on the back lit LCD screen. Alternatively the DSR-M can be controlled by a connected Pharma Test dissolution testing instrument. In any case no additional PC software is required to use the DSR-M. Usually the sampling probes inside the dissolution testing instrument are connected to the EPE auto sampling manifold, which is available for PTWS 310, PTWS 610, PTWS 1210 and PTWS D610. The motorized EPE lowers the sample probes into the corresponding sampling position which is pre-set for either 500 or 900 ml total media volume. A trigger signal starts the DSR-M sampling pumps so that the preset volume is withdrawn and dispensed into the vials or tubes which are in the sample racks. Only one sample line is required from the dissolution testing instrument via the sampling manifold since all liquid sampling and refilling is made through the same tubing. So no need for extra return tubing for refilling and automated tube flushing previous to the consequent sampling interval.

A typical automated System including the DSR-M includes the following equipment:

  •  A PTWS-series dissolution testing instrument including the TM manual tablet drop magazine, the EPE automated sampling manifold and full PTFE tubing installation
  • The DSR-M dissolution sampling robot with an integrated CAT-M valve-free piston pump module


  • Features integrated valve-free piston pumps for high precision
  • Modular design to allow auto media refill, dilution and transfer into sealed vials for six to twelve station dissolution baths
  • Up to 20 sampling cycles (10 cycles with dilution)
  • Less than 1% transfer error
  • Automated media replacement with CAT-MRM module without the need of separate refilling tubing lines (option)
  • Supports 0.45 micron filtration using MFC-12 manual filter changer and DSR-MVS valve station (option)
  • Sampling sequences are programmed direcly at the Pharma Test dissolution bath
  • Stand-alone mode available to support third party dissolution baths
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