This 6 station tablet dissolution bath with individual stirring speed control is ideal for R&D purposes.


USP/EP Tablet Dissolution Testing Instrument

The PTWS 120S is a 6-position, multiple 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 BP, DAB and Japanese Pharmacopeia section <15>. Its design for manual operation and ease of use.

Compact yet capable – the PTWS 120S dissolution tester features six individual stirring speeds.

Compact yet capable – the PTWS 120S dissolution tester features six individual stirring speeds.

User Interface

In keeping with our cutting edge design, a large color, 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 using a resistive touch screen and selection wheel technology.

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.

User interface LCD screen

User interface LCD screen

Stirring Tools

The PTWS 120S 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. PTWS 120S is capable to perform a staggered start for each of the six positions, which is essential in manual operation.

Stirring tools with MonoShaft™ design

Stirring tools with MonoShaft™ design

Vessel Centering System

The PTWS 120S features a rigid and precise three-point individual centering system for each dissolution vessel (picture shows view from below). 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. Each USP Borosilicate glass vessel has a batch code on top of the flange for easy visibility and positioned placement inside the water bath cover.

Lift Mechanism

The upper drive is motorized and electronically controlled it offers eight programmable positions: an upper cleaning and instrument qualification position and lower working positions are programmable depending on the type of stirring tool used.

The upper position offers ideal access to the stirring tools and vessels for a change of tools and cleaning steps between the dissolution tests. The motorized drive head lifting 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.

Heating System

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.

Vacuum-Moulded Water Bath

The vacuum molded water bath can easily be removed from the support frame for cleaning purposes. The water bath contains a water diffuser for faster heating and to ensure that heated water is evenly distributed throughout the whole bath. The bath is double walled to reduce the heat transfer to the outer environment saving internal heating and external cooling.

Space Requirements

A key point in today’s crowded labs is the footprint of the PTWS 120S. The space saving design of the PTWS 120S offers the user the choice between a 2×3 or a 3×2 configuration with a minimal space requirement of just 45cm by 65cm (width by depth). The display module can be mounted either of two positions on the drive head of the PTWS 120S instrument.

The touch screen can be attached in two different positions, either on the instrument's short or long side to make optimal use of limited laboratory bench space
All vessels can be accessed easily for manual sampling

The touch screen can be attached in two different positions, either on the instrument's short or long side to make optimal use of limited laboratory bench space

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  • Automated temperature check and log at all sampling times
  • Fully USP <711/724> and EP <2.9.3/4> compliant
  • 6 individually motorized stirred positions
  • Centrally located motorized lift drive to raise and
  • lower the drive head
  • Individually coded Borosilicate vessels
  • File up a nearly unlimited number of different test descriptions (methods)
  • CAN Bus technology offering instrument suitability check prior to start of a test run
  • Staggered start capability
  • Vessel low evaporation sealing covers
  • Removable water bath for easy cleaning
  • Drainage tap to empty the bath
  • Method management and CFR compliant user administration
  • User Access control
  • Optical and acoustic signals to inform about sampling intervals,
  • Timer count down function
  • Traffic Light optical information on display shows the instrument status by different colors (green = ready to use, yellow = preparing to use, red = error encountered)
  • OQ, PQ interval warning with programmable interval
  • USB port for remote control of the PTWS 120S
  • RS-232 port to connect a serial PT-RP80 report printer, printing date/time, sampling time information, selected sampling position, used stirring tools, media temperature, operator name etc.
  • I/O port for remote control of external instruments in automated applications, like DSR-M, Pumps and PTFC-2/8


  • 6 stirring positions, individually electronically regulated high precision drive system for each one of the 6 stirrers.
  • Grouping of stirrers, like 2 groups of 3, or 3 groups of 2 running at the same speed
  • Modular design to minimize bench space requirements
  • 3-point individual vessel centering system
  • Borosilicate glass vessels including extra low evaporation vessel covers
  • Individual vessel batch code at the top of the vessel flange for easy identification
  • Excellent access to all vessels
  • Eco saving double walled vacuum molded water bath
  • Motorized Drive Head lifting mechanism including head position programming facility
  • Screen saver functionality and count-down timer offers most important information at a glance (stirrer speed, bath temperature, time to next sampling interval, elapsed time, media temperature etc.)
  • Wake up functionality to start heating at a pre-programmed time
  • Ultra-fast heating system due to newly designed heat exchanger, saves up to 1/3rd of the heating up time compared to most other models
  • MonoShaft™ system to avoid re-adjustment of immersion depth
  • Staggered stirrer start feature for convenient manual sampling
  • Water diffuser inside the vacuum moulded water bath for even temperature distribution and fast temperature equilibration
  • Spring loaded pump assembly to eliminate vibration transfer
  • Extraordinary safety features for pump and heating system, flow control, digital temperature control, thermo switch, thermo fuse
  • Auto stirrer stop when drive lift is moved
  • Excellent stirrer shaft verticality inside the vessels due to central position of lift columns, drive head assembly and rigid anodized aluminum framework
  • Easy removal of the water bath from of the frame work for cleaning and maintenance work
  • Energy saving double walled bath option, less heat transfer into the lab environment, less power consumption during instrument operation
  • DQ/QC, IQ and OQ documents included free of charge

Technical Specifications

Parameter Specification
Display 6″, 320×240 pixel color LCD, illuminated
Data Entry Resistive touch screen, functional touch keys
Acoustic Signal Programmable acoustic signal for operator information
Timer Programmable sampling times, wake-up and sleeping mode, operation time information and timer count-down mode
Stirrer Position 8 programmable stirrer immersion positions (paddle over disk, transdermal cylinder etc.)
Testing Method Programming Unlimited number of different test descriptions can be stored on SD card
User Access Control Multiple level access control, CFR compliant
OQ, PQ control Programmable time periods to remind on QO or PQ testing
Printer External PT-RP80 report printer using long-life printer paper
Number of Stirred Vessels 6 (3 by 2 or 2 by 3 arrangement)
Standard Vessels 1 liter USP/EP Borosilicate glass vessel, each individually coded
Vessel Covers Ultra-low evaporation design (< 0.7% within 24h)
Individual Speed Control 25 – 250 RPM for each stirrer
Speed Accuracy ±2% of set speed, typically < 1%
Stirrer Shaft Wobble Better than 0.2 mm total run out
System Tools MonoShaft™ stirrer design, USP/EP apparatus 1, 2, 5, 6 tool adapter, cream cell, transdermal patch tools, each tool and vessel individually coded
Heating System Pump for water circulation and 1500W heater for fast heating up (230/240V units only)
Heater Range 25 – 45°C
Heater Accuracy ± 0.2°C inside the water bath
Heat Up Process Energy saving, programmable “wake up” heater function and “sleep mode”
Water Circulation Water circulated from external heating system through special diffuser inside the water bath
Vibration Elimination External heating system, spring loaded pump assembly
Calibration Built-in calibration procedures for speed, temperature control, OQ/PQ interval programmable including alarm indicator
Bench Space Requirement 45 x 65 cm (2 by 4) or 65 x 45 cm (4 by 2)
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

  • Eco saving double walled vacuum molded water bath
  • One set of stainless steel paddles
  • One set of batch coded 1000ml Borosilicate glass vessels
  • One set of depth adjustment balls
  • One bottle of ALGEX water preservative
  • Comprehensive documentation folder including:
    • User manual
    • DQ/QC instrument compliance test certificate
    • IQ documentation
    • OQ documentation
    • Instrument logbook
    • Compliance certificates for vessels and stirring tools
ALGEX Magenta

ALGEX Magenta

Water Bath Preservative – with Color Indicator, 250 ml

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  • Direct control of peripheral instruments via I/O port such as PTFC-2/8 fraction collector or DSR-M Sampling Robot
  • 2 liter vessel version (can also be used with 1 liter vessels)
  • 250 ml Mini Vessel set incl. mini paddle stirrers
  • Amber colored vessels for UV sensitive test materials
  • Full range of MonoShaft™ stirring tools available
  • Full range of certified validation tools available
  • PT-RP80 serial report printer

PT-RP80 Report Printer

Use the PT-RP80 serial report printer to print out the runtime report of the PTWS 120S.

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