Category Archives: Bath-Based

Distek, Inc. Releases Wireless In-Shaft Temperature Control and Monitoring for Model 2500 Dissolution Instrument

North Brunswick, NJ – Distek, Inc., an industry leader in pharmaceutical laboratory testing instruments, accessories and validation services, is excited to release an “optional” wireless in-shaft temperature control for the Model 2500 dissolution instrument.

The “patent pending” wireless in-shaft temperature sensors offer continuous vessel temperature control and monitoring from within the vessel without the need of an additional wired temperature probe and raising and lowering manifold.


“The innovative use of our patent pending wireless temperature sensor technology further enhances the Model 2500, returning much needed time and labor savings back to the dissolution laboratory”, says Jeff Seely, Vice President of Sales & Business Development, Distek, Inc.

For additional information contact Distek’s Corporate Office at +1 732 422 7585, by email at or visit

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Filed under Bath-Based, Dissolution, Model 2500

Model 2500 vs. 2100C

Model 2500

During a recent Model 2500 presentation we were asked the following:


“Besides the discontinuation of the 2100C, what additional justification would you recommend for us in replacing a 2100C with the new 2500?”


 Added Control and Compliance

  • The Audit Trail records the last 50 changes made to a method, should an investigation occur.
  • Three user access levels limit user abilities and permissions.
  • The 100 most recent test reports are saved, allowing them to be reviewed at a later date if necessary.

 Additional Time-Savings

  • The ability to store methods allows users to quickly select an entered method and run it without re-entering parameters.
  • TCS wake timer allows the bath to be pre-heated and ready for use prior to arrival of laboratory staff.

 Ease of Use

  • Intuitive touch-screen interface simplifies entry of key parameters (RPM/Temperature/Time) from one screen.
  • Firmware updates can be easily emailed or downloaded from the internet to a USB Key eliminating the replacement of firmware chips.

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Filed under Bath-Based, Model 2100C, TCS-0500

User Access Levels

In an effort to increase a laboratories control over dissolution system user privileges, Distek has incorporated three user access levels on the Symphony 7100 and Model 2500. Each access level differs in the actions users are allowed to execute and are detailed below.

Permissions for Manager, Advance User and User Level:

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Filed under Bath-Based, Bathless, Model 2500, Symphony 7100

Model 2500 Water Bath Dissolution System

Distek, Inc. is pleased to introduce their latest dissolution instrument, the Model 2500.  A descendent of the trusted 2100 Series, the Model 2500 offers a robust collection of system and user interface upgrades.

The Model 2500 Dissolution Test System offers ultimate flexibility and configurability while maintaining the reliability and ease of use that laboratories around the world have come to expect from the preceding four-generations.

New features include: a self-priming thermocirculator, wake up and sleep modes, integrated control of the optional Dosage Delivery System (DDS), USB printing, electronic qualification tracking and alerts, and an extensive list of user interface advancements intuitively accessed through the color touch screen display.

Distek has coupled these innovations with the core features of RPM and bath temperature monitoring, a seamless molded water bath, manual and automated methods, a smooth non-motorized drive head lift, and test volume flexibility (100 ml to 4 L).

“The Model 2500 is the culmination of combining technological innovation with tradition,” says Jeff Seely, Global Manager – Sales, Marketing & Technical Service, Distek, Inc.  “The hundreds of pharmaceutical companies and universities around the world that have purchased  a 2100 Series over the past three decades can upgrade to the Model 2500 with the confidence of a trusted brand.”

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Filed under Bath-Based, Model 2500

Intrinsic Dissolution


The intrinsic dissolution rate is defined as the dissolution rate of pure substances under the condition of constant surface area, agitation-stirring speed, pH and ionic-strength of the dissolution medium. 

The knowledge of intrinsic dissolution rate is vital in screening new drug candidates as it can help optimize the physiological effectiveness of new dosage forms. Distek has improved the performance and reliability of the rotating cylinder or “wood apparatus” with the paddle over stationary disk intrinsic apparatus. This is available in two configurations; standard for use with 1L vessel and mini for use with 100/200 ml vessels. The Distek design avoids the formation of air bubbles on the surface of the product and eliminates the potential of product “slippage” as can be the case with the wood apparatus.

 The Distek standard and mini intrinsic apparatus consists of steel punch, die, and base plate (fig. A).

Figure A

Test material is placed in the 0.8 cm diameter die cavity (optional cavity sizes are available) and the punch is inserted. The punch, die and press plate are placed in a laboratory press and kept under 2000 psi for 4-5 minutes. The press plate is disconnected from the die to expose a compact pellet of .5 cm2 surface area.

A Viton gasket is placed around the threaded shoulder of the die and a polypropylene plastic cap is screwed onto the threads. The assembly is then immersed, pellet side up, in the bottom of a flat dissolution vessel containing 900ml of dissolution medium at 37C. The paddle blade is positioned 6mm above the surface of the pellet and rotated at 50 rpm.

See USP 30-NF 25 General Chapter <1087> page 531 for more details.


Filed under Bath-Based, Bathless, Evolution 6100, Evolution 6300, Model 2100C

Height Adjustment Block

Setting your Distek Dissolution tester apparatus 1 and 2 to the proper USP defined height using Distek’s height adjustment block increases efficiency.  It allows for a rapid change between apparatus 1 and 2 without having to remove the shaft and reset the proper height. The height block is located on the side of your Evolution 6100, 6300 and Model 2100C labeled paddles or baskets (red arrow).

 To set the proper height follow these steps: 

1) Raise the drive head of the unit to the highest position.

2) Loosen the shaft collar (blue arrow) with an allen wrench and raise the shaft half way.

3) Turn the height adjustment block (red arrow) to the horizontal or neutral position.  At that point, you will not be able to read the text (paddles or baskets) from the front of the unit.

4) Lower the drive head until it sits firmly on the horizontal height adjustment block.

5) With paddle blades installed on all the shafts, lower the drive head until the paddle blades touch the bottom of the vessels.

6) Tighten the shaft collars with an allen wrench.

7) Raise the drive head.

8) Turn the height adjustment block to paddles and lower the drive head until it sits on the height adjustment block.

9) The height is now set to the appropriate height per USP, 25mm +/- 1mm.

10) The height can verified using the Distek height-chek tool.

 To use baskets:

1) Raise the drive head of the unit.

2) Replace the paddles with basket adapters when using detachable shafts and stirring elements.

3) Turn the height adjustment block (red arrow) to baskets.

4) Lower the drive head until it sits on the height adjustment block.

5) Verify.

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Filed under Bath-Based, Bathless, Evolution 6100, Evolution 6300, Model 2100C