The PTWS 100 is a 6 position, single drive compact tablet dissolution testing instrument for solid dosage forms as described in USP chapter and EP section as well as the DAB and Japanese Pharmacopeia section . 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 100 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).