USP <788> - Particulate Matter in Injections

What it says

General Chapter <788> describes methodology for detecting and quantifying subvisible particulate matter in injectable products, using light obscuration particle count testing as the primary method, with microscopic particle count testing as an alternative or confirmatory method, establishing acceptance criteria for particle counts at specified size thresholds.

Paraphrased for plain-language clarity. Always verify against the current published regulation text.

What it means in practice

• Particulate matter control is a fundamental patient safety consideration for injectable products, since particulates introduced intravenously can pose direct embolic or other clinical risks with no equivalent concern for most non-injectable dosage forms.
• Light obscuration testing, the primary method, can be affected by inherent product characteristics such as color, viscosity or the presence of proteins in biological products, sometimes requiring the microscopic method as an alternative when light obscuration is not suitable for a specific product.
• Particulate matter sources can include the manufacturing environment, container-closure system interactions, and even the drug substance or excipients themselves, meaning particulate control connects to environmental monitoring, container-closure compatibility and formulation considerations together.

What inspectors look for

• Whether the test method selected, light obscuration or microscopic, is appropriate and validated for the specific product's physical and optical characteristics.
• Whether particulate matter excursions are investigated for root cause, connecting to potential environmental, container-closure or formulation sources rather than treated as an isolated laboratory finding.
• Whether particulate matter testing is performed at appropriate points across the product lifecycle, including stability testing, not only at initial release.

Related regulations