USP <787> Subvisible Particulate Matter in Therapeutic Protein Injections

USP General Chapter <787> establishes an enforceable compendial test for subvisible particles specifically tailored to therapeutic protein injections. It parallels USP <788> in test methods and acceptance criteria but addresses the practical challenge of limited sample availability in high-value biologics, such as monoclonal antibodies and pre-filled syringe products. The key advantage of <787> is its allowance for reduced sample volumes and modified pooling strategies while maintaining the same safety standards.

Applicability: Therapeutic protein injections only (not all parenterals).

Rationale:

Standard <788> pooling volumes can be prohibitive for small, high-cost protein products; <787> provides a scientifically justified alternative without relaxing requirements.

Regulatory context: Enforceable when referenced in monographs or submissions; complements informational guidance in <1787>/<1788>.

Test Methods: Same as USP <788>:

• Light Obscuration (LO): Preferred automated method.
• Microscopy: Alternative when LO is unsuitable.

Acceptance Criteria: Identical to <788> for containers ≤100 mL:

• ≤ 6000 particles ≥10 µm per container
• ≤ 600 particles ≥25 µm per container

Procedural Adaptations: Allows reduced pooling/sample volumes for therapeutic proteins, making testing feasible for small, costly lots.

Context with Modern Characterization
While <787> provides the required test for lot release, the informational chapter USP <1787> should be consulted for a modern, risk-based approach to fully characterizing proteinaceous particles using a broader toolkit of orthogonal methods (e.g., Flow Imaging).