With standard gravimetric dosing
PT-DDS4 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.
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.
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.
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.
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.