Weighing and control technology in pharma

Medicines and medical devices are among the first products sold to consumers that must be 100% safe and thoroughly checked to strictly comply with industry regulations before they can be marketed.

To monitor the production and packaging process and ensure the correct weight and completeness of the packages, pharmaceutical companies employ inspection systems that can be applied during the processing of raw materials, primary or secondary packaging, and final packaging.

Among the most important in-line inspection systems for pharmaceutical products are checkweighers, to identify non-compliant weights, and industrial metal detectors, to detect ferrous and non-ferrous contaminant particles within the product.

Checkweighers enable precise control of the dosage of medicinal ingredients, even in very light products such as eye drops or tablets. Additionally, they perform a completeness check of container boxes as, through weight, they can detect the absence of a blister, for example, or an instruction leaflet.

Metal detectors, on the other hand, allow the detection of ferrous and non-ferrous contaminant particles that may have accidentally entered the bulk or packaged medicine during various stages of production, such as in blister packs, boxes, or bottles.

But what is the regulatory framework in force?

The regulatory framework

The World Health Organization (WHO) laid down in 1969 the first guidelines regarding quality measures for the production of pharmaceutical products to ensure that any medicine or medical device moving in the global market is consistently produced and controlled to the quality standards appropriate to their intended use. 
These are called the GMP (Good manufacturing practice) and describe the minimum standard that medicines manufacturers must meet in their production processes.
More than 100 countries have incorporated the WHO GMP provisions into their national medicines laws, so these guidelines have become compulsory to comply with for the worldwide pharmaceutical industry.

Good Manufacturing Practices establish rules regarding the sourcing of raw materials, traceability, and production data recording, as well as good practices for workers.

They regulate the production premises and machinery that manufacture and package medicines, specifying where they should be installed and how they should be maintained. Their structure must minimize the risk of production errors and be easily sanitized to prevent contamination, dust or dirt formation, and any adverse effects on product quality.

For controlling individual production phases, high-precision weighing instruments and scales must be provided. 

These equipment undergo regular calibration and verification.

Nemesis weighing solution

In the production of medical equipment, pharmaceuticals, and biotechnologies, the role of inspection and quality control machinery is to:

  1. Check the filling level of packages
  2. Ensure the integrity and completeness of the packaging
  3. Guarantee product traceability
  4. Detect any potential contamination from metals.

Checkweighers perform the first three functions, while combined machines, which include checkweighers and metal detectors, perform the fourth.

10 good reasons to purchase a pharmaceutical checkweigher

1. 100% net weight control with resulting fulfillment of market legal requirements and brand reputation protection
2. Missing components check 
3. Full traceability of the whole production batch 
4. Give-away reduction and consequent money saving
5. Real-time filler monitoring and adjustment  thanks to dedicated software
6. Quick and precise product sorting and classification by weight 
7. Enhanced production efficiency 
8. Statistical production data recording, analysis and reporting 
9. Constant product quality 
10. Labour saving

S Series checkweigher

For the Pharma Industry, Nemesis has developed the S Series Checkweigher, designed to meet  the modern demands in the field, with the exclusive target of complying with the GMP requirements and the strictest quality control standards, like 21 CFR referred to as by the American Agency for Food and Drug Administration.

For this reason, Nemesis provides with its checkweighers the necessary software package to ensure the reliability of all electronic records as required by the CFR Title 21 Part 11 regulations and to certify that all stages of the machine's lifecycle within the company, from installation to use, to calibrations and periodic checks of accuracy and proper functioning, have been carried out according to industry standards, as per the manufacturer's instructions (IQ/OQ/PQ).

S Series main features


  • Ultimate accuracy tapes allowing a top-class display resolution up to 0.01g even at the highest industrial speed rates. A stable and reliable weighing  is also ensured by the sturdy machine chassis as well as its brushless motors.
  • A throughput of 600 ppm with maximum belts speed up to 120 m/min
  • Capacity from 1g up to 600g with weighing accuracy of ± 0.005 g
  • Weighing Autolearning procedure thanks to the EasyWeighⓇ technology
  • Stainless steel design for the highest hygiene requirements
  • IP Protection: IP54 as a standard; IP65 available in case of harsh environments
  • Suitable for all kinds of packaging: plastic bottles, bags, sachets, blister packs, cartons, small bottles and small aerosols.

From 3 to 6 conveyor belts

Polyurethane belts

Multi-tape belts*

*Where an extremely high degree of accuracy is required, there is a special Multi-tape available that reduces the total weight on the load cell, thus improving the level of accuracy.

Feeding screw

For cylindrical products to be appropriately fed and spaced, the infeed screw conveyor is the best solution. It is particularly useful for small bottles or eye drops.

EasySet servo-assisted feeding belts

For a stable and safe feeding of cylindrical products, even tall ones, feeding belts can be added to the existing production line with no need for interruption or cutting.

Automatic ejection system

Depending on product shape and weight, different automatic ejectors can be available.

The most common ones in pharma are single and double airblast ejectors (on the left) as well as high-speed pneumatic ejectors (on the right).

Safety devices

To comply with GMP regulations, S Series Checkweigher is equipped with the following compulsory safety devices: 

  • Air pressure switch, to ensure a constant pressure level and a resulting smooth machine operation
  • Belt protection tunnel, to isolate production
  • Rejection photocell, to confirm non-compliant products have actually been discarded
  • Reject bin full photocell, to advise when reject bin is full 
  • Lockable reject bin, because only authorized personnel may have access to non-compliant items and correctly dispose them.

Nemesis solution to detect contaminants

M Series Combined Checkweigher and Metal Detector

The metal detector is an essential inspection system in the pharmaceutical industry. It allows for the immediate detection of ferrous and non-ferrous contaminant particles accidentally introduced during production stages in loose or packaged tablets, liquid medicines, and medical devices in general. To ensure the best performance and maximum detection accuracy, Nemesis offers combined solutions of metal detectors installed on checkweighers.

Ejectors and reject bins

Non-conforming products in terms of weight and those contaminated must be rejected and stored separately by law; consequently, combined checkweighers and metal detectors must be equipped with two separate reject bins

While those not conforming in weight can potentially be reprocessed and reintroduced into production, those contaminated must be discarded and subsequently collected in protected areas. For safety reasons, only authorized personnel can retrieve and dispose of them properly

For this reason, the reject bins of the metal detector must be equipped with a locking mechanism.

Two basic data to know

When choosing the right metal detector, it is essential to know two key elements:

 1) The dimensions of the product to be inspected, especially the height, to select the metal detector antenna with the aperture as close as possible to the product to ensure the best scanning.

 2) The type of packaging of the product, what material it is composed of, and whether it contains metal

The presence of aluminum foil, for instance, can affect the detection of ferrous contaminants.

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