PTWS 100D and PTWS 100S
6-Station Dissolution Testing Instrument

The PTWS 100 is a 6 position, single drive compact tablet dissolution testing instrument for solid dosage forms as described in USP chapter <711/724> and EP section <2.9.3/4> as well as the DAB and Japanese Pharmacopeia section <15>. It is supplied with a staggered start feature for each of the six positions. The upper drive is electronically controlled to offer two positions: an upper cleaning and a lower working position. The electronically driven lift mechanism is located centrally above the water bath. This assures that the whole lift drive mechanism is positioned in a way so that the tool shafts are always kept parallel and at a 90° angle to the vessel walls when in the working position.

The PTWS 100 features the 3CS three-point individual centering system for each dissolution vessel. The vessels are held in position by three adjustable noses and are inserted into the instrument support framework. The access points for sampling as well as the openings for the tools are contained in an auxiliary, low evaporation, vessel cover.

The blow moulded water bath can easily be removed from the support frame for cleaning purposes. The bath cover can also be easily unscrewed for cleaning. The water bath contains a water diffuser for faster heating and to ensure that heated water is evenly distributed throughout the whole bath.

The heating system is contained in a separate stainless steel housing. The connections between the heater and the bath are made by „quick connect“ fittings for easy connection and disconnection. Water is pumped through the system using a powerful, yet quiet, circulation pump. The pump itself is spring mounted (to limit vibration transmission) and the flow-through heater is protected from overloading (overheating in case of control electronics failure) via a thermal fuse as well as a thermo switch for added security. With service and maintenance in mind, access to the compact pump and heater section is easily achieved without having to move the main body of the instrument.

The PTWS 120 uses the Pharma Test MonoShaft™ design. Tools consist of the main shaft plus interchangeable tool heads (adapters). The main shaft remains in place in the instrument regardless of the tool head being used. The clearance of each tool from the vessel base will always be correct once the main tool shaft has been installed and qualified with any one of the tool sets once. Each stirrer can be raised by hand into a convenient position for easy vessel removal or insertion.

A key point in today’s crowded labs is the footprint of the PTWS 100. The space saving design of the PTWS 100 offers the user the choice between a 2×3 or a 3×2 configuration with a minimal space requirement of just 45cm by 60cm (width by depth).

In keeping with our cutting edge design, a touch screen allows control of the various mechanical features of the instrument such as the tool stirring speed, lift drive and heater. The instrument control is menu driven. Visual signals on the display inform the user of the status of critical instrument parameters, e.g. bath target temperature not reached. Access to the instrument can be password controlled if required. If certain operational parameters form a regular feature of the daily routine, then these can be incorporated into a test method for faster set up. These parameters can be tool speed, target bath temperature, sampling time points and so on. The test method memory capacity is almost limitless. As soon as the test is started, a screen saver can be activated with the most important information displayed in large script so that this information remains visible even at time when the operator is not standing directly in front of the instrument.

The PTWS 100D is supplied with a single DC motor drive while the PTWS 100S includes individual stepper motors for each one of the 6 stirring stations. Both versions are also available as a 2 litre version.

For offline automation with fraction collection the PTFC-2 fraction collector as well as either a peristaltic or a piston pump can be added to the PTWS 100.  Using the PTWS 100 within an automated system offers the operator full access to the vessels before and at the end of a run as the complete drive head is lifted electronically. Sampling sequence timing, sampling volume and the optional media refilling process are programmed using the menu system of the PTWS 100 instrument. No external software is necessary in this system. In-situ sampling ferrules are placed into the PTWS 100D vessels through cover holes. Each ferrule holds a 5 or 10µ PP sinter filter. When the tablets have been dropped into the dissolution vessels the automated sampling process starts. If the refilling option is used media refilling will start automatically after a sample has been withdrawn.

It is also possible to use the DSR-M dissolution sampling robot which features the capability of sample dilution and offers excellent sampling accuracy via the fully integration piston pump module. Like the PTFC-2, the DSR-M can be fully controlled by the PTWS 100.

For an online automated system it is possible to use a UV/VIS spectrophotometer with a multiple-cell-changer. The spectrophotometer and pump of such a system is controlled by the powerful WinDiss ARGUS dissolution software. WinDiss ARGUS features drivers for most commonly available UV/VIS spectrometer types, like Agilent 8453 Diode Array, or conventional UV/VIS monochromatic spectrophotometers (preferably double beam and scanning versions) such as the T70, Cecil CE and Perkin Elmer Lambda series as well as drivers for many popular types of pumps. The PTWS 100 can be used in stand-alone mode in these systems.

Other instruments of the Pharma Test dissolution instrument series are the PT-DT70, PTWS 310 for 1 and 2 litre vessels, PTWS 610 (6+2), PTWS 1210 (12 + 2), PTWSD610 (dual drive 6+6), and the 5 ltr. vessel instrument type PTWS 4000.


  • Fully USP <711/724> and EP <2.9.3/4> compliant
  • 6 stirred positons
  • 3CS 3-point individual vessel centering system
  • Centrally located electronic lift drive
  • Staggered start capability
  • Options – Individual speed control for each station (PTWS 100S), PT-DL1 data logger
  • Interfaces – RS232 to connect data logger, I/O port for remote control in offline automated applications
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