CEI-MS-07 — Sub-visible particulate matter in reconstituted peptide solutions

§1Scope

§1.1Scope

Applies to reconstituted peptide solutions intended for parenteral administration, and to the assessment of whether a lyophilised cake reconstitutes to a solution free of visible and sub-visible particles.

§2Principle

Particles are counted and sized either by light obscuration, in which a particle passing a sensing zone reduces transmitted light in proportion to its projected area, or by microscopic examination of a filtered membrane. Protein and peptide aggregates are frequently transparent and are systematically under-counted by light obscuration, which is the principal reason the Institute treats a particulate result for a peptide as necessary but not sufficient.^[1,2]

§3Apparatus and reagents

§3.1Apparatus

• Light-obscuration particle counter with a calibrated sensing zone
• Filtration apparatus and membranes for the microscopic method
• Binocular microscope with a calibrated graticule
• Laminar-airflow enclosure for sample preparation

§3.2Reagents and reference materials

• Particle-free water, verified below the counting threshold
• Calibration particle standards of stated nominal diameter

References cited on this page

References are numbered in order of first citation in this document. Each superscript in the text links to its entry below.

1. United States Pharmacopeial Convention. General Chapter ⟨788⟩ Particulate Matter in Injections. United States Pharmacopeia — National Formulary (USP–NF) 2024;USP 2024 Issue 1. identifier not held by the Institute
2. United States Pharmacopeial Convention. General Chapter ⟨1225⟩ Validation of Compendial Procedures. United States Pharmacopeia — National Formulary (USP–NF) 2024;USP 2024 Issue 1. identifier not held by the Institute

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