Visual Inspection
Method Introduction
Visual inspection aims to determine the absence or presence of visible particles within parenteral products.
Visual inspection is performed by trained human operators using their naked eyes. The European Pharmacopoeia and the Japanese Pharmacopoeia specify inspection conditions, such as light source, handling procedure, inspection time, and background, whereas the United States Pharmacopoeia (USP) does not give instructions.
Especially during formulation development, where visual inspection is mainly used to detect proteinaceous particles, a ranking of the extent of visible particle formation can be beneficial to differentiate between formulations with only a few visible particles and those with a high number of visible particles. Within the “Deutscher Arzneimittel Codex” (DAC), a scale and procedure is described, which ranks the presence of visible particles in scores from 0 (no particles visible within 5 s) to 10 (particles visible immediately and clearly in significant quantities within 5 s). In many cases, company- or project-specific scores are developed to rate the formation of visible particles during formulation development.
Applications
During formulation development, a visual inspection is performed to judge if particles are formed within formulations, for example, during forced degradation or stability studies. For this application, a small number of vials/containers are usually inspected, and a rating of the extent of visible particle formation can help differentiate between formulations.
The main challenge of visible inspection is the probabilistic nature of the test, even when performed under standardized conditions.
The lower particle size detection limit and the outcome of visual inspection depend on various factors, such as the examination settings (light source and background, auxiliary equipment), the operator (training, eyesight, fatigue, concentration), primary packaging (vial type and size, filling volume), formulation properties (viscosity) and particle properties (concentration, refractive index, shape). Depending on the listed factors, particles larger than 50-100 µm can usually be detected as visible.
Quality and Biosafety Level
We provide all our analytical services with the highest quality standards. Experienced scientists carry out each project, and a scientific reviewer comprehensively checks every report or data presentation.
We offer this technology with the following quality and biosafety levels:
R&D level
We offer this method under R&D. Our GRP system assures the highest-quality research standards.
Up to biosafety level 2
This method can be applied to nucleic acids, viruses, cells, viral vectors, including lentiviruses and more.
Analytical Method Development, Qualification and Validation
For common sample types, we can often apply standardized methods with little setup effort. However, when needed, our experienced analytical experts create or optimize custom methods tailored to your active pharmaceutical ingredient, product type and development phase.
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