Control weight and hardness - tablet press
March 22, 2005
Courtoy tablet press control system that control the tablet weight and hardness simultaneously, reducing waste and improving consistency.
A breakthrough innovation from Niro Phama Systems solves a control dilemma that has faced the pharmaceutical industry ever since automated tablet presses came into use. The problem has been the balancing of weight and hardness of the tablets. Previous technologies required consequential steps by skilled operators in order to keep both weight and hardness to specification.
Niro?s engineers have crafted a unique solution that separates the two control systems for simultaneous weight and hardness control on a standard rotary tablet press.
Advantages of the Dual Control System:
Allows independent control of both weight and hardness.
Reduces trial-and-error operator adjustments for changes in powder characteristics.
Fine tunes processing to meet all tablet specifications.
Decreases waste of valuable formulation in non-spec tablets.
The patented Dual Control System physically separates the two control loops to work on separate areas of the press. Weight is controlled at the pre-compression stage, and hardness is controlled during main compression. The Dual Control System is now available as an option on all Courtoy Modul? tablet presses.
One of the major problems in the operation of tablet presses is the variation in feed powder properties, both from batch to batch and within each batch. The operator must make frequent incremental trial-and-error changes to meet processing specifications for tablet weight, thickness, and hardness.
Previous technology required control of the rotary tablet press to be based on either ?force control? or ?displacement control.? The force control principle is based on measurement of final compression force under constant tablet thickness. It applies to applications where forces are high. The displacement control principle is based on measurement of thickness variations under constant force. It is more accurate for soft tablets and much easier for the operator to set up.
If the powder characteristics change in a system using force control, the control system has to be corrected to bring the average tablet weight back to the target value. This correction is the re-calibration of the primary control loop and is performed by changing either the target value of the compression force or the main compression height of the machine. In both cases the hardness can be affected.
The Dual Control System Solution
To overcome this problem, Courtoy has developed the Dual Control System, combining force control and displacement control in a unique manner. Displacement control at the pre-compression stage fixes the tablet weight while standard force control technology keeps the hardness constant during the final compression by keeping the compression force constant.
The weight control loop and the hardness control loop are totally separate, measuring process variables at different compression stations and acting on independent variables of the compression cycle. Because the two loops are separated and both are running continuously, the result is independent, continuous, and simultaneous control of both tablet weight and hardness, a true Dual Weight / Hardness Control System.
The tablet press operator now has three options: tablet weight control from the classic Courtoy displacement measurement with extended dwell time at pre-compression; force control at main compression; or Dual Control with displacement weight control at pre-compression and hardness control at final compression.
For a demonstration of the Dual Control System, visit Courtoy at the Niro booth #1537 at Interphex 2005 or call Niro Pharma Systems.
North America:
Niro Pharma Systems
Niro Inc.
9165 Rumsey Road
Columbia, MD 21045 USA
Antonie Van Zegbroeck, Business Unit Manager ? Courtoy Tablet Presses
Tel.: +1-410 997 7010
Fax: +1-410 997 5021
For inquiries outside North America:
Niro Pharma Systems
Courtoy N.V.
Jan Vogeleer, Managing Director
Tel.: +32 2 363 8307
Fax: +32 2 356 0516

Niro Pharma Systems is the world leader in providing advanced processing solutions for solid dosage forms to the pharmaceutical industry. Based on a dedication to research and durable quality, Niro Pharma Systems offers a wide range of solutions, from individual pieces of equipment to complete integrated plants, by uniting the state-of-the-art technologies of Aeromatic, Buck, Collette, Courtoy, Fielder, Nica and Niro.
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