Enhancing pharmaceutical quality with visual inspection test sets

What is Visual Inspection in pharma?  

Visual Inspection is a GMP process step that involves carefully examining parenteral finished products, containers and packaging materials to identify defects, impurities and any deviations from the intended quality standards. This inspection process is crucial to ensure that products meet the stringent requirements set by regulatory bodies and industry standards. Visual Inspection contributes to the safety of pharmaceutical products before they reach the patients. 

The role of Visual Inspection test sets 

Visual Inspection test sets are positive controls: the containers in these sets contain each one known visual defect that is to be detected by a human operator or by an automated inspection machine. These positive controls are designed to facilitate the evaluation, validation and training of visual inspection systems and operators. Test sets typically contain between 10% and 25% of known defects, while the rest of the containers in such a set are confirmed good units that don’t show any of the defects considered by the client. 

Some key points about Visual Inspection test sets: 

1. Purpose: Visual Inspection Test Sets are used to check how well Visual Inspection systems and operators detect defects, contaminants, and irregularities during qualification. They are also helpful for training operators and fine-tuning automated inspection systems. An increasing trend involves the creation of highly specialized test sets exclusively comprising particulate matter defects. These sets are used in Threshold of Size studies to find the smallest particle size that can be detected 70% of the time with different particle materials.
    
2. Standardization: the samples in Visual Inspection test sets are manufactured to mimic different types of defects, including particulate matter, glass particles, container defects, and cosmetic imperfections. For standardization purposes, not only microscopic measurements are applied but also other product characteristics can be taken into account such as colour, turbidity, surface tension of viscosity. 
    
3. Validation and qualification: Visual Inspection test sets are used during the validation and qualification processes of Visual Inspection equipment and operators. They help ensure that inspection systems are functioning correctly and that operators can reliably identify potential defects. 
    
4. Regulatory Compliance: regulatory bodies, such as the United States FDA and the European EMA, recommend the use of Visual Inspection test sets as a way to ensure compliance with industry standards for particulate matter testing. The use of these standardized sets has become a regulatory expectation.
    
5. Types of defects: Visual Inspection test sets can include a wide range of particles, such as glass fragments, fibers, hairs, scratches or rubber fragments. Also different product defects are mimicked: discolorations, increased turbidity, mix-up and under- or overfill.Among container defects we typically see scratches, cracks, glass inclusions, deformations and various stopper or plunger defects. 
    
6. Innovations: at eyetec we specialize in the development of Visual Inspection test sets for freeze-dried (lyophilized) products and the development of placebos when the product is not available. Last but not least we are also developing test sets for training and qualification of operators that will ‘read’ media fills. This important step in Aseptic Process Validation (APV) is aimed to detect containers that are microbially contaminated often seen as increased turbidity and/or discoloration of the media.  
    
7. Treshold-of-Size (ToS) studies: Visual Inspection test sets enable companies to assess the performance of inspection systems or human operators in detecting defects of different sizes and characteristics. This information can be used to optimize the inspection process if needed. It is also becoming a regulatory expectation to have such data available. 

Overall, Visual Inspection test sets are critical tools for maintaining the quality and safety of pharmaceutical products. They contribute to the overall performance of Visual Inspection processes by ensuring that defects and contaminants are reliably identified, ultimately safeguarding patient health and product reputation.