Quality in the pharmaceutical industry is vital when dealing with a product and its associated production processes. It helps ensure the product achieves its therapeutic effects, gains customer trust, and achieves regulatory compliance.
Quality is achieved in a pharmaceutical product when it fulfills different product-level parameters set by standardization and regulatory bodies, one of which is weight.
Weight is verified and ensured at different stages in the pharmaceutical industry, including the final product. Accurate weight ensures accurate dosage delivery to the patient, a critical factor in the patient’s health. Regulatory compliance is also ensured, which can become problematic for the pharmaceutical organization if found under- or overweight. The equipment used to weigh is known as a Checkweigher.
What is a checkweigher system?
A checkweigher is an automated machine that checks the weight of items passing through or on its sensor. It is typically used for finished packaged pharmaceutical products in the packaging department to ensure the package has its required weight, which is a function of the quantity of drug as claimed on the packaging, and the amount of raw material present in the individual unit. They are installed at the end of the bottle, blister, or carton filling line.
The checkweigher can be programmed for an acceptable weight limit and to reject all packages that falls outside the permissible limits. If a package is over- or underweight, the checkweigher automatically rejects it through a rejection mechanism. It also includes a visual panel that displays the weight of the packages in the weighing section.
Two types of checkweigher are used in the pharma industry. They are In-Motion and Static
In-Motion Checkweigher
In-motion checkweigher systems, also called Dynamic Checkweigher, weigh the package when the package in motion or during movement. They weigh the package on the go and compare it with the acceptable limit. If it falls within the acceptable limit, it is allowed to proceed to the accepted point. On the other hand, if it is over or under the acceptable limit, it is rejected in the motion state without stopping the checkweigher and packaging machine.
They are used for high-speed packaging lines due to their capability of processing high-speed packages. The load cell is sensitive enough to measure the weight without being affected by vibrations and high-speed movement.
It includes a rejection mechanism to remove the over- or under-weight package as it moves on the checkweigher system.
Static Checkweigher
Static checkweigher measure the weight of packages when they are stationary. In contrast to in-motion checkweigher, these weighers require manual loading. They take some time before they calculate and display the weight.
They are used to measure small or delicate packages, to measure a portion of a packaging line to ensure weighing operations, for quality checks, and in process laboratory operations.
Static checkweigher have a simple design without complex machinery, control, and instrumentation. Since they require manual handling, they can slow down the packaging processes. However, they are more reliable, accurate, and low-cost.
Components of the Pharma checkweigher system
A checkweigher is a simple machine usually consisting of the following parts.
In-feed Conveyor - The in-feed conveyor transfers packaged drugs to the weighing station. This part is only included in the in-motion type.
Weighing station: This station consists of a load cell to measure weight. It also includes additional components, such as stabilizers and vibration control components.
Rejecter: This part is only included in the in-motion type and is used to reject the packaged drug that is under- or overweight. It can consist of a pneumatic-controlled arm or air nozzle that activates to remove the packaged drug from the conveyor belt.
Automation components: Control the overall workings of the checkweigher system. Fewer and simpler components are used for static types, while complex automation components and systems are used for in-motion.
Importance of checkweigher in the pharma industry
Let’s discuss the importance of Checkweigher in the pharma industry
Ensures Production Accuracy
Checkweighers can make precise weight measurements to ensure production efficacy. Although packaging machines are integrated with inspection and safety systems to prevent over- or under-packing, in a fast-paced environment, various factors can contribute to machine error in the packaging line.
Checkweighers installed at the final packaging line enable the pharmaceutical industry to detect any package without a product. They also increase productivity by minimizing waste related to packaging material, resulting in a cost-effective production process.
Prevent Recalls
Pharma manufacturers are bound to recall any product that does not meet the required quality and regulatory requirements, including insufficient dosage requirements. Product recalls cost pharmaceutical manufacturers financial, reputational, and time costs.
One final verification through a checkweigher after the final packaging is an effective way to prevent product recalls. It acts as an extra layer of protection to prevent packaging discrepancies and recalls.
Real-time analysis
Control components used in Checkweigher can track the weighing process and analyze it in real time. They allow users to view the weight of actual packaging and adjust parameters if necessary.
Ensures patient safety
Integrating a checkweigher into the final packaged product ensures patients receive an accurate dosage. They can help reduce packaging errors and verify product authenticity. Patient safety also ensures enhanced customer trust and increased market share.
Features of the Pharma checkweighers system
Let’s discuss some features of checkweighers
Ability to check weight at high speeds
The checkweighers can precisely measure the weight of the packaged drug at high speeds. Their vibration control and high sensitivity enable offsetting errors that arise with high speed, making them a reliable system for measuring weight.
The high-speed weight checking enables it to integrate with any packaging machine or line. Because today’s packaging machines pack pharma products at considerably high speeds, it is critical that the associated machinery should also be high-speed.
Precise measurements
Checkweighers can measure the weight of an individual package at high speeds. Their design enables precise measurements, often down to milligrams.
Rejecting packages based on weight range
A checkweigher can be integrated with a rejection system that enables it to reject a package that does not fall within the limits. The rejection mechanism is a dedicated function of the checkweigher system, independently of any other machine, such as packaging or cartoner machines.
The checkweigher’s dedicated load cell and automation components enable it to control its function independently. The rejecter mechanism can be installed using a pneumatic-controlled arm or nozzle. Once the rejected package passes through the rejection arm, it automatically moves away from the conveyor belt.
The accept/reject threshold is set independently on the weigher, which controls the rejector mechanism.
Real-time data collection
Checkweigher can be programmed with real-time data indicating the number of units passed, the number of rejects and accepts, and the reason for the reject.
The real-time data can then be used to adjust machine parameters online to correct and limit rejection. The data can also be analyzed for process improvement using data analytics techniques.
Alarm management
The checkweigher can be provided with an alarm system to generate an alert if the package falls out of the acceptable range. The alarm can be configured with an alert system for personnel interference, such as visual or audible. It can also be configured with the system to stop the conveyor. Other parameters for the alarm can also also be configured, such as if a particular number of pieces have been rejected.
Applications of the checkweigher system in the Pharma Industry
Some applications of a checkweigher in the pharma industry include the following
Individual Weighing
The most common application is measuring the weight of an individual dosage unit, which represents the quantity of the required chemical composition. An accurate weight represents the desired quantity of chemical or API included in the dosage.
Sorting
A checkweigher can be used to sort products based on their weight. If the weight of any product or item falls above or below the acceptable range, it can automatically be separated from the pool of acceptable products. This will prevent abnormal weights from reaching the market, preventing market complaints, regulatory fines, and recalls.
Data Collection
A checkweigher can be used to collect data about a specific product batch and a weight range. The data indicates the trend of product and weight variation, which can be tracked back for various purposes, such as historical analysis, performance (equipment or process) monitoring, and improvement.
Some challenges related to the checkweigher system in the Pharma Industry
Checkweighers also face challenges in a dynamic environment like pharmaceuticals, such as
The checkweigher consists of a load cell, which includes a sensitive coil. A slight variation or displacement in the coil arrangement indicates the weight. Sometimes, due to vibrations in the load cell’s mechanical structure, weighing readings fluctuate.
Checkweigher, like other weighing systems, requires calibration at regular intervals. If not performed, the Checkweigher can become faulty, indicating faulty readings. Additionally, calibration is a regulatory & standardization requirement. For this purpose, it is necessary to calibrate with proper record system
The output of the Checkweigher is also sensitive to the alignment of the support frame. A misalignment can fluctuate the readings from their acceptable range.
About the Author
Muhammad Asim Niazi has a vast experience of about 11 years in a Pharmaceutical company. During his tenure he worked in their different departments and had been part of many initiatives within the company. He now uses his experience and skill to write interested content for audiences at PharmaSources.com.
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Pharma Sources Insight July 2025
