Viral Nanofilter Integrity:Using Variable-Pathlength UV-Vis Spectroscopy for the Gold Nanoparticle Test

摘要

Viral filtration (VF) using nanofilters removes endogenous and/or adventitious viruses from biologic drug-substance manufacturing processes (l). The gold particle test (GPT) is performed as part of postuse integrity testing — to complement postuse leakage testing — for cellulose filters such as Planova 20N filters from Asahi Kasei Corporation. First, a proprietary gold-colloid solution matched to the filter type (e.g., 20N) is filtered through the test article. That filter's pore-size distributioncan be assessed using spectrophotometric absorbance readings of the integrity-test solution — e.g., 1:10 dilution of Asahi Gold Particle solution AGP-HA20 to test Planova 20N — and the correct filtrate sample (minimum volume collected for measuring absorbance) to calculate the gold-particle removal rate as a logarithmic reduction value (LRV).