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How Product Inspection Drives Quality in Liquid Pharmaceuticals

In liquid pharmaceuticals, the stakes could not be higher: the correct dosage and usage can literally be a matter of life and death. Marco Pelka, Market Manager PCE of Mettler-Toledo explains how manufacturers and packaging companies in this field can harness product inspection to ensure they produce high-quality liquid pharmaceutical products.

As of the end of May 2022, more than 1.28 billion COVID-19 doses had been administered in Europe1 since this unprecedented immunisation campaign began in 2020. Both here and worldwide, there is no doubt that the pandemic vaccination programme has done much to raise the profile of research into, and deployment of liquid pharmaceutical drugs. The liquid pharmaceutical market has been growing due to the importance of biologics and cancer drugs that are produced more effectively in liquid form. Historically drugs were produced in solid form, which takes years of development to ensure shelf-life stable solid doses. As demand has pushed for faster-to-market drugs, manufacturers must keep pace with production methods to make that happen. The market has changed, and the production of the COVID-19 vaccine has been a catalyst for change in producing more liquid pharmaceuticals directly into bottles, vials and ampules as standard packaging formats.

Manufacturers in liquid pharma understand that they will face the most serious consequences if they get things wrong. If, for example, they provide a product with an incorrect dosage size, it could be fatal for a patient. The other main issue is counterfeit medicines. The US has addressed this in the Drug Supply Chain and Security Act (DSCSA) in order to provide measures to minimise counterfeiting, and most other territories follow this lead.

With these issues in mind, liquid pharma manufacturers must operate at the forefront of product quality standards, ensuring that their dosages are correct and safe to protect consumers and patients. To comply with DSCSA, the packaging, labelling and in-pack product information must be accurate and up-to-date as well as be able to trace their products through manufacturing processes and the supply chain. Delivering transparency and proof of their legitimacy against counterfeits will help in securing safer pharmaceuticals.

Of course, these issues must be addressed while still operating efficiently, to get safe, cost-effective liquid pharma products to market quickly. There can be no compromise on quality standards, and this means that product inspection solutions must be deployed in both manufacturing and packaging processes in order to follow Current Good Manufacturing Practice (CGMP) guidelines set by the US Food and Drug Administration (FDA). For manufacturers, there are also some very specific needs to address. As discussed below, these steps support quality assurance in liquid pharma packs:

  1. Fill Level Control The nature of liquid pharma products is that they must contain an exact amount of dosage, usually held in small, fragile packs such as glass vials and bottles. There is a lot that can go wrong here: the dosage amount might be under or over-filled; the bottles themselves may not be completely uniform, with slight, but very important, fluctuations in tare weight; the size and shapes of these vessels make them inherently prone to toppling over and breaking during processing.

Both the unfilled and filled weight of each bottle or vial might be extremely light, and therefore weighing systems must be capable of very sensitive and accurate weighing. Checkweighers using high-performance Electro-Magnetic Force Restoration (EMFR) load cells can meet the precision and accuracy required. Careful handling of this kind of fragile primary packaging, including sorting and rejection mechanisms, is a must to reduce the risk of downtime caused by broken or damaged vials. All of this is required to happen at standard production speeds.

The use of a check-weigher that is capable of these levels of precision and product handling delivers further benefits to liquid pharma manufacturers. It provides weighing data that demonstrates the attainment of certified weighing standards required to support compliance with industry and government regulations. It also brings with it an economic argument, as well as a product quality argument. Accurate weighing that identifies over- and under-filling errors help meet weights and measures compliance, reduces the costs involved in over-filling and product give-away, and lessens the potential for reputational damage – and the costs that extend from that – to the manufacturer.

  1. Completeness Control

In liquid pharma, a product is only complete when its packaging includes instructions for use, most commonly in the form of a folded leaflet. The difference in weight between a pack with a leaflet and that of one without can be very subtle and weighing technology of great precision and sensitivity is required. Checkweighers are able to detect these slight variations in weight and can do so without disrupting production speeds. They can also feature a countercheck function, which checks rejected products to ensure that they have been correctly identified as off-weight.