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Filtration is universally used in biopharmaceutical processing. For example, in upstream processing for sterilizing-grade filtration of cell culture media or in various downstream operations, such as clarification, filtration of intermediates, and in critical final filling applications. It is well known that filtration devices can release a certain level of organic compounds within the first filtrate fractions, which can be measured as total organic carbon (TOC). The compounds are primarily released from the surface of its construction materials. This includes typical polymer constituents that migrate from the material, as well as compounds which are formed during sterilization by irradiation. The level of compounds present on a surface is reduced significantly during rinsing of filters. Therefore, these can be defined as "rinsables". A deeper understanding of filter rinsing characteristics and chemical composition of a rinse solution is relevant for process design and risk mitigation, especially in high-risk applications. This publication provides the analytical and mathematical tools to measure and evaluate rinsing curves obtained from different sterilizing-grade membrane filter capsules. Total organic carbon (TOC) content, high-resolution mass spectrometry, ion chromatography, and headspace GC-MS were used to determine the composition of rinsing fractions and to follow the course of the rinsing curve. The required, filter-specific parameters Bulk Volume per Surface area (BVS) and Rinsing Volume per Surface area (RVS) are introduced. They are used for calculating minimum bulk and rinsing volumes of filters that lead to TOC concentrations below the threshold of 500 µg/L for Water for Injection. Three relevant filtration cases in biopharmaceutical manufacturing are discussed together with best practices for evaluation and use of BVS and RVS parameters. Results of a verification test are presented and discussed., (Copyright © 2021. Published by Elsevier B.V.)

Users of single-use (SU) components need extractables data to demonstrate material safety for regulatory bodies before incorporation in the biopharmaceutical process. In this context, the correct use of such extractables data is key to deriving realistic risk assessments for SU devices. In this paper, a standardized extractables approach was used that provides comprehensive extractables information including identity and quantity. The combination of extractables data obtained from different components of a sterile filter capsule, such as the filter cartridge and housing, and the scaling thereof is presented. A sterile filter type including polyethersulfone membrane was extracted with pure water and pure ethanol at 40°C for 24 h. The organic extractables were identified and their concentration quantified using state-of-the-art analytical methods such as gas chromatography-mass spectrometry for semivolatile compounds together with headspace sampling for volatile compounds, and liquid chromatography coupled with high-resolution mass spectrometry. The extractables detected were assigned to the materials of filter construction. The evaluation showed that the extractables quantities per device depended on the surface areas of the contact materials, such as the filter membrane, and also on the plastic parts. This paper confirms the validity of a so-called component approach and a scaling concept to calculate extractables data for SU filters of different sizes with short-term contact. LAY ABSTRACT: In the biopharmaceutical industry, a large number of SU system combinations with a variety of different sizes are used. Suppliers of such diverse SU systems and assemblies cannot perform extraction studies for all of the different configurations and sizes individually. It is acceptable in this industry to use component approaches and scaling concepts to provide extractables data for SU systems and assemblies derived from a dedicated extraction experiment. This paper shows the applicability of a so-called component approach and of a scaling concept to calculate extractables data for sterile polyethersulfone membrane filters and filter capsules of different sizes. Selected extraction conditions allow scaling calculations according to underlying physical principles. The extractions were performed under short-term contact, for example, 24 h, to ensure that the release of extractables was diffusion-controlled. The results demonstrated that extractables quantities depend on the surface area of the contact material. Membrane-related compounds were scalable with the membrane area, whereas polypropylene (PP)-related compounds were scalable with the PP contact area., (© PDA, Inc. 2019.)

Sterile filters are ubiquitous in biopharmaceutical manufacturing processes. Because such filters are in direct contact with the process fluid, profiling of the extractables is of utmost importance. The work presented here reveals the extractables profile from filter cartridges for sterilizing-grade filtration, which were obtained from six different vendors. All filters contain a 0.2 μm polyethersulfone membrane for sterile filtration combined with a polyethersulfone pre-filter with retention rates spanning from 0.4 to 0.6 μm. These filter cartridges are designed for use in stainless steel housings which allow for in-line steam sterilization. A combination of different analytical techniques such as (headspace) gas chromatography-mass spectrometry, ultra-performance liquid chromatography-high-resolution mass spectrometry (electrospray ionization), inductively coupled plasma mass spectrometry, total organic carbon, non-volatile residue, conductivity, and pH value were applied to develop a comprehensive extractables profile on a qualitative and semi-quantitative basis. Pure ethanol and purified water were used as extraction media. The extractables profile consisted of various polyolefin-related extractables, additives such as antioxidants and degradation products thereof, hydrocarbons, and processing aids in addition to membrane-related extractables. LAY ABSTRACT: Filter cartridges or other filter products for sterile filtration are currently most commonly made of polymeric materials such as polypropylene, and a filter membrane material such as polyethersulfone. These materials will usually release chemical substances upon extraction in the laboratory ( extractables ), or upon application in biopharmaceutical processing ( leachables ). Potential extractables and leachables are additives used to tailor the physicochemical properties and to protect the polymeric materials, or degradants of these substances, or they arise from substances used during the manufacturing of the filter cartridges. Multiple analytical techniques were applied here to investigate the concentration and chemical nature of extractables obtained upon application of two distinct extraction solvents. Typical extractables found were antioxidants or releasing agents in addition to compounds originating from the polyethersulfone membrane., (© PDA, Inc. 2018.)