Reliable and handy lab companion to effectively degas, heat and precisely dose dissolution media


Media Preparation and Degassing System

Media degassing or “de-aeration”, pre-heating to a temperature of 37°C and absolutely precise gravimetric dispensing according to the recommendations and demanded for dissolution testing from the US FDA authorities are standard for the Pharma Test PT-DDS4 media preparation and degasing system. De-aeration is generally recommended to prevent the formation of bubbles on the dosage form surface, which may cause a variation in active dissolution rates, by virtue of surface obscuration.

PT-DDS4 Media Preparation and Degassing System

PT-DDS4 Media Preparation and Degassing System

Test Procedure

Effective media de-aeration is one of the most important requirements for a successful tablet dissolution test. USP reference standard tablets (RST) for PVT tests in particular, react very sensitive to ineffectively de-aerated media. Often the test fails to arrive at the required results for the release, even if all technical parameters of the dissolution bath in use have been checked and passed the tests. A save and efficient way of media de-aeration of un-dissolved oxygen (O²) is offered by the techniques the PT-DDS4 is using.

PT-DDS4 offers volumetric dosing as an option.
The instrument includes a large display and an integrated protcol printer.

PT-DDS4 offers volumetric dosing as an option.

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The prepared media (buffer) is filled by means of vacuum or manually into the storage and heating tank of the instrument. While the media is heated, it is being constantly circulated under vacuum within the tank. Because of this way of operating, the PT-DDS4 provides fully de-aerated and preheated media ready to be dispensed into the USP dissolution vessels. Therefore another huge advantage of media preparation in this way is the time saved during the startup of subsequent dissolution runs, because the media is already at the required testing temperature of 37°C. PT-DDS4 is more effective than other available instruments, because the de-aeration process can be maintained for as long as required, as opposed to instruments which only de-aerate during the actual dispensing.

LCD Screen

PT-DDS4 features a large back-lit LCD screen. The user menu offers the possibility to program the dispensing (weight) volume, the temperature to pre-heat the media and the total de-aeration time. All information including dosed weight/volume and statistics can be printed via the built-in thermo printer.

Easy Access

The portable nature PT-DDS4 instrument offers the user easy servicing of many dissolution baths. The built-in pre-heating tank is easily removable for cleaning. Open the drainage valve and empty the tank of any medium left. Flush the tank again and repeat the software assisted process. When the media has to be changed, a tube flushing run is automatically done previous to any dispensing.

Handling of Foaming Media with PT-DDS4

To improve the degassing and dosing of foaming media, like SDS with the Pharma Test PT-DDS4 media preparation system, a new alternative inlet tube system is available now. A curved inlet tube can be used as an alternative to the standard diffuser inlet. The curved inlet tube directs the medium against the barrel wall, where it can gently flow down the tank, thus preventing an excessive foam build-up. The inlet tubes can be changed freely by the user. The inlets are secured by a knurled head screw. An upgrade kit for existing PT-DDS4 instruments is available as well.

Gravimetric Dosing is the Most Accurate Method of Liquid Dispensing

In this mode, the medium is directly dispensed into the dissolution vessel, which is placed safely in its stand during filling. The dosing volume can be adjusted within a range of 250 to 5,000g with an accuracy of ±0.5%, max. ±1ml. This accuracy is much better than what any current Pharmacopoeia requires. Enter the media density to correct the dosing. The temperature can be adjusted as well, within a range of 30.0°C to 50.0°C with an accuracy of ± 0.5°C. The media is constantly circulating while the vacuum level is kept constant.

Volumetric Dosage is Selectable as well

This mode of dosage is very convenient and time effective for the end user. Here, the de-aerated medium is filled directly into the dissolution vessels which are installed in the dissolution bath. The design of the filling arm ensures a slow filling along the side of the vessels to avoid oxygen saturation while filling.

Online Buffer Mixing Using the Built-in Electronic Load Cell (Balance) is Available as Well

Simply enter the amount and density of the buffer (range from 100g to 5,000g) to be filled into the pre-filled storage tank.


  • Fully USP and EP compliant
  • De-aeration and heating of approx. 24 liters of media at the same time
  • Pre-heating of media; target temperature adjustable from 30 – 50°C
  • Adjustable gravimetric dosing range: 250 – 5,000 g
  • Adjustable volumetric dosing range: 250 – 5,000ml (optional)
  • Online buffer mixing, adjustable buffer dosing range: 100 – 5,000g (optional)
  • LC display and keypad to show and enter data, like product information, batch no., media density, etc.
  • Live information about the remaining tank volume; minimum 3 liter
  • File up to 16 de-aeration procedures (methods)
  • Built-in adjustment and calibration program for the digital load cell and flow-meter
  • Built-in thermal printer or network option to report the dosed media weight or volume and to document of adjustment and calibration results


  • De-aerates to approx. 35% of rest gas content (residual oxygen less than 5 ppm inside PT-DDS4 container)
  • Pre-heats your media to save time during start-up of dissolution tests
  • Fill-up program under pressure (connect directly to factory de-min. water supply)
  • Fill-up program under vacuum (prime from any external container)
  • Can be upgraded to de-aerate and dispense SPS foaming media
  • Can be used to directly dose into any vessel arrangement inside the dissolution bath
  • Special adapter to handle foaming media available (optional)
  • The instrument is movable and fits underneath most laboratory benches
  • Includes a balance (load cell) and all accessories for gravimetrical dosing
  • Good access to the media tank, easy to control the cleaning and test procedure
  • The only instrument which offers a software supported calibration program to validate and calibrate dosing accuracy using a certified 1 kg weight
  • Dosing performance test possible using built-in strain gauge
  • Correct dosing accuracy by entering density of media (changes because of temperature or solvent used)
  • Maximum of 2 liters waste when media change has to be done
  • Noise protected, max. noise level approx. 55dB
  • IQ/OQ documents included free of charge


Technical Specifications

Parameter Specification
Dosing Range 250 – 5,000g – gravimetric method

250 – 5,000ml – volumetric method

Dosing Accuracy ±0.5% of selected volume – gravimetric method

±0.8% of selected volume – volumetric method

Tank Volume Approx. 24 liter
Filling Volume Not less than min. 10 liter
Dispensing Time for 1 Liter Approx. 45 – 60 seconds
De-aeration and Heating Time 24 liters within approx. 30 – 45 minutes
Display LED backlit LCD, 320×240 pixels, 9″ diagonal, approx. 90x120mm
Data Entry Alpha numerical keypad
Method Memory Store up to 16 methods
Printer Thermo printer, 24 characters
Interface RS232 port
Vacuum Level 0.4 bar absolute
Temperature Range 30.0 – 50.0°C
Temperature Accuracy ±0.5°C
Heater Capacity 900W
Calibration Built-in calibration procedures for digital load cell (weight), digital flow meter (volume) temperature control
Height of Dispenser 130cm from ground floor
Space Requirements 550 x 700 x 900 mm (Length x Width x Height)
Packaging Dimensions Approx. 1070 x 970 x 780cm (Length x Width x Height)
Net / Gross weight Approx. 75 / 110 kg
Certification All components certified to USP / EP requirements
CE / EMC Certification All CE / EMC Certification provided
Validation All IQ & OQ documents included

We reserve the right to make technical changes without any prior notice.

Included in the Standard Scope of Supply

  • Gravimetrical dosing set-up
  • Electro polished stainless steel tank – max. capacity approx. 24 liters
  • Stainless Steel dosing dish to hold dissolution vessels
  • Comprehensive documentation folder including:
    • User manual
    • DQ/QC instrument compliance test certificate
    • IQ documentation
    • OQ documentation
    • Instrument logbook


  • Volumetric dosing system
  • pH buffer dosing system
  • Upgrade kit for foaming media
  • Support stand to take up to 6 USP vessels
  • Full range of certified validation tools including DO² tester to read the amount of de-aeration available

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