Introduction to USP <790>
USP <790> "Visible Particulates in Injections" is the compendial standard that defines requirements for the visual inspection of injectable pharmaceutical products. Published by the United States Pharmacopeia, this chapter establishes the conditions under which inspection must be performed, the qualifications required of inspectors, and the acceptance criteria for visible particulate contamination.
For pharmaceutical manufacturers, compliance with USP <790> is not optional — it is a regulatory expectation enforced by the FDA during facility inspections and product reviews. Understanding and implementing its requirements correctly is essential for maintaining product quality and avoiding regulatory actions.
Scope and Applicability
USP <790> applies to all injectable pharmaceutical products including small-volume parenterals (SVPs), large-volume parenterals (LVPs), and ophthalmic solutions. The chapter requires that every unit of an injectable product be individually inspected for visible particulates prior to release.
This 100% inspection requirement applies regardless of the inspection method used — whether manual, semi-automated (SAVI), or fully automated (AVI). The method must be validated to demonstrate adequate detection capability for the defects of concern.
Inspection Conditions
USP <790> specifies precise conditions for manual visual inspection:
- Lighting intensity: 2,000–3,750 lux at the inspection point for clear containers; higher intensities may be needed for amber or opaque containers
- Background: Non-glare, black and white backgrounds for contrast enhancement
- Viewing distance: Approximately 25 cm from the container
- Inspection time: Adequate time per unit to allow detection of particulates (typically 5–10 seconds per container for manual inspection)
- Container manipulation: Gentle inversion and swirling to mobilize settled particles
These conditions must be documented, controlled, and verified as part of the inspection program. Deviations from specified conditions can significantly impact detection capability and must be justified through validation data.
Inspector Qualification
USP <790> requires that all inspectors be qualified to demonstrate adequate visual acuity and detection capability. Qualification typically involves:
- Vision testing: Corrected near visual acuity of 20/20 or better, tested annually
- Training: Documented training on inspection procedures, defect recognition, and equipment operation
- Performance testing: Demonstration of adequate detection using characterized defect test kits
- Requalification: Periodic requalification to confirm continued performance
The Knapp test methodology, described in USP <1790>, provides a statistical framework for inspector qualification by comparing individual inspector performance against an expert panel.
Relationship to USP <1790>
While USP <790> establishes the requirements, USP <1790> "Visual Inspection of Injections" provides detailed guidance on implementation. USP <1790> covers topics including:
- Inspection program design and validation
- Statistical methods for inspector qualification (Knapp testing)
- Probability of detection (PoD) assessment
- Equipment qualification for AVI and SAVI systems
- Trending and continuous improvement
Common Compliance Gaps
Based on FDA warning letters and industry experience, the most common USP <790> compliance gaps include:
- Inadequate lighting verification and documentation
- Insufficient inspector requalification frequency
- Lack of characterized test sets for qualification
- Missing validation data for inspection time limits
- Inadequate trending of reject data
How YB Inspection Can Help
YB Inspection provides characterized defect test kits specifically designed for USP <790> compliance activities. Our kits enable rigorous inspector qualification, Knapp studies, and ongoing performance monitoring. We also offer consulting services to help you design and validate your inspection program against USP <790> requirements.
Contact us to discuss your USP <790> compliance needs, or explore our defect test kits for inspector qualification.