Assessing biologic/toxicologic effects of extractables from plastic contact materials for advanced therapy manufacturing using cell painting assay and cytotoxicity screening

Plastic components are essential in the pharmaceutical industry, encompassing container closure systems, laboratory handling equipment, and single-use systems. As part of their material qualification process, studies on interactions between plastic contact materials and process solutions or drug products are conducted. The assessment of single-use systems includes their potential impact on patient safety, product quality, and process performance. This is particularly crucial in cell and gene therapy applications since interactions with the plastic contact material may result in an adverse effect on the isolated therapeutic human cells. We utilized the cell painting assay (CPA), a non-targeted method, for profiling the morphological characteristics of U2OS human osteosarcoma cells in contact with chemicals related to plastic contact materials. Specifically, we conducted a comprehensive analysis of 45 common plastic extractables, and two extracts from single-use systems. Results of the CPA are compared with a standard cytotoxicity assay, an osteogenesis differentiation assay, and in silico toxicity predictions. The findings of this feasibility study demonstrate that the device extracts and most of the tested compounds do not evoke any measurable biological changes on the cells (induction  ≤ 5%) among the 579 cell features measured at concentrations  ≤ 50 µM. CPA can serve as an important assay to reveal unique information not accessible through quantitative structure-activity relationship analysis and vice versa. The results highlight the need for a combination of in vitro and in silico methods in a comprehensive assessment of single-use equipment utilized in advanced therapy medicinal products manufacturing.

Dimethylsilanediol from silicone elastomers: Analysis, release from biopharmaceutical process equipment, and clearance studies

Polysiloxanes are considered one of the most important commercial families of synthetic elastomers. They are frequently employed in biopharmaceutical manufacturing equipment as flexible single-use solutions due to superior material properties and compatibility with diverse sterilization methods. Extractables and leachables (E&L) testing is essential in qualifying such equipment, involving extraction studies to assess the potential release of compounds from plastic components for risk assessment. Silicone releases oligomeric siloxanes and small hydrolysis products, with dimethylsilanediol (DMSD) being the main hydrolysis product found in significant concentrations in aqueous process solutions. DMSD presents challenges for analysis, requiring specifically tailored analytical methods to detect it, which are commonly not applied in standard E&L screening tests. In biopharmaceutical manufacturing, it is relevant to consider the potential of DMSD to repolymerize into silicone oil when specific process parameters are altered. This may lead to interactions with drug ingredients, including proteins, resulting in the formation of aggregates. We synthesized and characterized DMSD using X-ray structure analysis and established an HPLC method with a refractive index detector to investigate the release of DMSD from commercially available silicone tubing used in drug manufacturing following autoclaving and irradiation. Subsequently, we assessed typical biopharmaceutical downstream operations for effectively removing this compound from the process stream.

Biosorption of process-equipment-related leachables (PERLs) in biomanufacturing: A quantitative approach to study partitioning of PERLs in a cell culture system

The assessment and potential risk of process equipment-related leachables (PERLs) in the production of biopharmaceuticals and cell therapeutics using single-use (SU) equipment has been discussed previously. However, potential interactions of cells with PERLs have not yet been considered. Here, we present a quantitative adsorption study of neutral, organic small-molecule leachable compounds - known for extractables & leachables (E&L) analysis of SU equipment - in aqueous suspensions of CHO and T cells. The solid-water partition coefficient K_d was obtained for all compounds that showed adsorption. The findings implied that hydrophobic interactions are dominant; however, there was no unambiguous correlation between the derived adsorption coefficient K_d and the octanol-water partition coefficient K_ow. Interestingly, a maximum affinity of both cell types to the leachable bis(2,4-di-tert-butylphenyl)phosphate, which is known to be detrimental to cell development, was observed. A comparison of both cell types revealed that they generally interact with the same compounds in most cases but to different extents. Using partition coefficients enables estimation of the concentrations of leachable compounds associated with the biomass phase and in the aqueous suspensions and could be used for risk assessment of SU systems in biopharmaceutical and cell therapy (CT) manufacturing processes.

Equivalence study of extractables from single-use biopharmaceutical manufacturing equipment after X-ray or gamma irradiation

Single-use (SU) devices and assemblies used as manufacturing equipment in the biopharmaceutical industry require comprehensive qualifications. These qualifications include the assessment of compounds released from SU devices in contact with the process fluids, and how these leachable compounds potentially influence process performance, drug product quality, and patient safety. SU suppliers need to provide comprehensive qualification data for several parameters, for both new products and product changes, such as changes in the sterilization process applied to the SU device. The introduction of X-ray irradiation as an alternative to the currently used and established gamma irradiation of SU devices represents a situation where robust data is required to demonstrate equivalency between these two radiation technologies. Here, we present the results of a comprehensive extractables study for three SU components, bags, tubing, and sterilizing grade filters, evaluated after X-ray and gamma-ray irradiation. The selected study conditions were set up to allow a direct comparison of the results from the two sterilization methods, and to allow conclusions to be made on the impact of irradiation type on the polymers and their additives. Orthogonal analytical methods are applied to identify and quantify all organic compounds present. The data package provided here supports risk assessments for application of irradiated SU equipment in biopharmaceutical manufacturing. The formation of reaction products and the fundamental chemical pathways are discussed and found to be independent of the irradiation type. The results demonstrate the equivalency of both irradiation methods for extractables from plastic components used in pharmaceutical and biopharmaceutical manufacturing.

X-ray sterilization of biopharmaceutical manufacturing equipment-Extractables profile of a film material and copolyester Tritan™ compared to gamma irradiation

The biopharmaceutical industry gains enormous flexibility in production processes by using sterilized preassembled single‐use devices. Gamma irradiation is an established sterilization technology that may be restricted in the future by the availability of ⁶⁰Co as irradiation source and irradiation capacities. X‐ray technology is considered an alternative type of radiation for sterilizing SU equipment. In the context of extractables and leachables—one concern connected with the use of single‐use process equipment—the effect of X‐ray irradiation on the extractables profile of the materials needs to be compared to established gamma irradiation to qualify this alternative technology. An approach is presented to obtain robust and comprehensive extractables data for materials used in SU devices after sterilization either using X‐ray or gamma irradiation. A careful selection of the test items and the test design allows a one‐to‐one comparison of data obtained from a combination of orthogonal analytical techniques. The extractables of a modern SU film material and the copolyester Tritan™ are evaluated. The data presented allow a risk evaluation on the safety of this new sterilization modality for biopharmaceutical applications. It is demonstrated that the extractables profile of a polymer is not affected by the type of irradiation used for sterilization.

Using extractables data from single-use components for extrapolation to process equipment-related leachables: The toolbox and justifications

Quantitative information on process equipment-related leachables (PERLs) is required for process qualification and within a safety assessment. Extractables data for single-use equipment are suitable and applicable if the extractables study conditions fit or are bracketing the expected conditions of use. It is necessary to extrapolate extractables data when the expected in-use conditions are not covered by the test conditions. Methods for such quantitative extrapolation of extractables data toward potential PERLs are therefore needed. They are comprehensively described in this publication and include: scaling of extractables data for devices of different sizes adjusted to process-volumes, extrapolation to temperatures different from the extraction temperature, extrapolations to different solvent compositions, extrapolation to various contact times, and the combination of extractables data from individual components to assess assemblies. These extrapolation methods yield extractables data as if an extractables study had been performed. The methods presented are consistently derived from basic physicochemical principles. The relevant, underlying physical parameters are obtained from extractables experiments and are compared with published data. The applicability and justification of the proposed calculation methods are discussed and benchmarked against experimental findings.

Using Extractables Data of Sterile Filter Components for Scaling Calculations

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.

Comparative Extractables Study of Autoclavable Polyethersulfone Filter Cartridges for Sterile Filtration

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.

Analysis and evaluation of single-use bag extractables for validation in biopharmaceutical applications

This paper describes an approach of extractables determination and gives information on extractables profiles for gamma-sterilized single-use bags with polyethylene inner contact surfaces from five different suppliers. Four extraction solvents were chosen to capture a broad spectrum of extractables. An 80% ethanol extraction was used to extract compounds that represent the bag resin and the organic additives used to stabilize or process the polymer films which would not normally be water-soluble. Extractions with1 M HCl extract, 1 M NaOH extract, and 1% polysorbate 80 were used to bracket potential leachables in biopharmaceutical process fluids. The objective of this study was to obtain extractables data from different bags under identical test conditions. All the bags had a nominal capacity of 5 L, were gamma-irradiated prior to testing, and were tested without modification except that connectors, if any, were removed prior to filling. They were extracted at 40 °C for 30 days. Extractables from all bag extracts were identified and the concentration estimated using headspace gas chromatography-mass spectrometry and flame ionization detection for volatile compounds and for semi-volatile compounds, and liquid chromatography-mass spectrometry for targeted compounds. Metals and other elements were detected and quantified by inductively coupled plasma mass spectrometry analysis. The results showed a variety of extractables, some of which are not related to the inner polyethylene contact layer. Detected organic compounds included oligomers from polyolefins, additives and their degradation products, and oligomers from the fill tubing. The concentrations of extractables were in the range of parts-per-billion to parts-per-million per bag under the applied extraction conditions. Toxicological effects of the extractables are not addressed in this paper.

LAY ABSTRACT

Extractables and leachables characterization supports the validation and the use of single-use bags in the biopharmaceutical manufacturing process. This paper describes an approach for the identification and quantification of extractable substances for five commercially available single-use bags from different suppliers under identical analytical conditions. Four test formulations were used for the extraction, and extractables were analyzed with appropriately qualified analytical techniques, allowing for the detection of a broad range of released chemical compounds. Polymer additives such as antioxidants and processing aids and their degradation products were found to be the source of most of the extracted compounds. The concentration of extractables ranged from parts-per-billion to parts-per-million under the applied extraction conditions.

Determination of "extractables" on polymer materials by means of HPLC-MS

In biopharmaceutical processes, in the area of food and medical technology a variety of devices is used. These devices consist of various polymers. The detection and identification of potential extractables from these polymers during application are requested by the regulatory bodies. For risk and toxicity assessment, both identification and quantification of extractables are necessary. This article describes the development of a LS-MS methodology transfered from an established HPLC-UV-VIS method for full extractables analysis of sterile-grade filtration cartridges.

Study of protein adsorption effects on crossflow filtration using BSA and milk protein

Three membrane materials were tested under similar conditions to determine the effects of membrane material on the performance and cleanability of the filters. The membrane materials investigated were stabilized cellulose (Hydrosart, Sartorius Corporation), cellulose triacetate, and polyethersulfone; all having a 10 kilodalton molecular weight cutoff. Stabilized cellulose is a cellulose-based membrane material, modified for low non-specific protein adsorption combined with high pH-resistance. When analyzing the data, three phenomena were considered: adsorption of protein to the membrane, gel layer formation, and osmotic pressure due to concentration polarization. Throughout these studies, the effects of a gel layer and the osmotic pressure were approximately equivalent in all cassettes. However, the stabilized cellulose was resistant to protein adsorption while the other two membranes exhibited significant decreases in permeate flux due to adsorption. Using a 0.2% BSA (MW = 67,000 kD) solution with a crossflow rate of 5 L/min and transmembrane pressure of 35 psi, the permeate flux through the stabilized cellulose membrane was 3% lower than the baseline saline flux, whereas the cellulose triacetate and polyethersulfone membranes lost 33% and 60% of baseline flux, respectively. The decrease in flux occurring in the latter two membranes is due to adsorption. Another study evaluated adsorption by alternating between crossflow and static operation. After three cycles, the stabilized cellulose maintained the original crossflow flux level. The polyethersulfone lost cumulatively 17% of its crossflow flux after three cycles and the cellulose triacetate lost 13%. The stabilized cellulose and polyethersulfone membranes were also evaluated using a milk solution. The results indicate that the stabilized cellulose is not susceptible to adsorption of any of the milk components while the polyethersulfone permeate flux was limited by adsorption. The saline flux of the stabilized cellulose immediately after testing with the milk solution was 3% lower than the baseline flux, while the polyethersulfone membrane saline flux was 81% lower. The results consistently indicated that, unlike the cellulose triacetate and polyethersulfone membranes, the stabilized cellulose membrane was not subject to adsorption.

Crossflow filtration for CHO cell separation by microfiltration using crossflow systems

Chinese Hamster Ovary (CHO) cells are used for fermentation of high value proteins in the pharmaceutical- and biotechnology industry. During the fermentation process the cells are grown under specific conditions in a defined media. The CHO cells produce extra cellular proteins. Separation and purification of these proteins result in the final product of high value. The production steps utilized in any bio-pharmaceutical process must deliver the target protein with high purity and yield. The first step in the production process is the separation of cells from the rest of the fermentation broth. Currently, stacked depth filters are used in this separation. The disadvantages with this method are:- 1) low product yield (high hold-up/wetting volume) and 2) the messy "clean-up" that is inherent with stacked filters. One of the main process requirements is that the CHO cell removal be accomplished with low cell mortality. This eases the subsequent process steps to purify the target protein with high yields free of DNA and other intracellular proteins. Additionally, the CHO cells can be reused.

Heterogeneous expression of c-myb protein in human leukemia detected by simultaneous two color flow cytometric analysis

The expression of c-myb mRNA and protein was analyzed in fresh leukemic cells by Northern-blot analyses and by immunofluorescent staining using monoclonal c-myb specific antibodies. Staining of the cells was evaluated by flow cytometry. The results demonstrate c-myb mRNA expression predominantly in acute lymphocytic leukemia (ALL, 4/4 cases), acute myeloic leukemia (AML, 17/17) and chronic myeloic leukemia (CML, 12/12) but rarely in chronic lymphocytic leukemia (CLL, 1/17). Immunofluorescent analyses revealed expression of c-myb protein in the nucleus of ALL (5/7) and AML (9/9) with a good correlation of c-myb-positive cells and with the number of proliferating (Ki67-positive) blast cells.

Chromosomal rearrangements caused by the aberrant transposition of double Ds elements are formed by Ds and adjacent non-Ds sequences

The Ds-induced unstable sh-m6258 allele is caused by the insertion of at least 45 kb of non-sh DNA. Genomic clones spanning the two junctions of sh sequences with insert sequences were isolated and analysed. The long insert in the sh-m6258 allele is bordered by Ds sequences on either side. A 3 kb double Ds structure which consists of one complete Ds element of approximately 2 kb and one half Ds element of approximately 1 kb was found in the sh-m6258 allele at the junction between the 3' region of the sh locus and the insert. At the junction between the 5' region of the sh locus and the insert a half Ds element is present. This truncated Ds element was probably left behind after the excision of a 2 kb Ds element from a 3 kb double Ds structure similar to that found at the 3' junction. Sequence analysis of the insert sequences beyond the Ds elements demonstrated that the long inserts in both the sh-m6258 and the sh-m5933 alleles originated from the same contiguous chromosomal segment in their common progenitor strain. One revertant derivative of the sh-m6258 allele was investigated. In the revertant strain, which displays a normal non-shrunken phenotype, a 2 kb Ds element is present at the site of the 45 kb insert in the mutant allele. This 2 kb insertion, which is located in the last but one intervening sequence of the Sh gene, does not inhibit expression of the gene.(ABSTRACT TRUNCATED AT 250 WORDS)