Peer Review Article | Open Access | Published 20th December 2023
An Investigation of the Visual Impact of the Combined Exposure to Residual Cleaning Agents and Vaporized Hydrogen Peroxide on Materials used in Barrier Systems
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Keywords: Vaporized hydrogen peroxide, Material compatibility, Residual cleaning agents, Material integrity
Vaporized Hydrogen Peroxide (vapor-phase hydrogen peroxide, vH₂O₂) treatment is the main approach for sporicidal surface bio-decontamination in restricted access barrier systems and isolators. Prior to vH₂O₂ exposure, surfaces are cleaned to prepare the barrier system for the decontamination cycle, removing surface residues that could impede the cycles effectiveness. The presence of residual cleaning agents alongside vH₂O₂ exposure could potentially impact the integrity and longevity of materials, necessitating a comprehensive understanding of these interactions.
To gain more knowledge about the influence of cleaning agents and vH₂O₂, various materials were exposed to a combination of cleaning agents and vH₂O₂ in order to visually assess the interaction.
Vaporized Hydrogen Peroxide has emerged as a valuable tool for bio-decontamination due to its ability to efficiently eliminate a wide range of microorganisms, including bacteria, viruses, and spores . The penetration of vH₂O₂ is limited, so surfaces are cleaned to remove contaminants that may interfere with vH₂O₂ penetration and effectiveness prior to vH₂O₂ exposure. While studies have investigated the compatibility of materials with vH₂O₂ or cleaning agents alone [2,3], the interactions between residual cleaning agents and vH₂O₂ have received limited attention until now.
Residual cleaning agents might persist even after thorough rinsing, potentially influencing the interaction of the vapour phase gas with materials. Reactive components within cleaning agents could react with vH₂O₂, probably leading to material deterioration, discoloration, or altered mechanical properties. Additionally, accumulated residues within surface microstructures might hinder vH₂O₂ diffusion, thus impacting its efficacy. Investigating these combined effects is pivotal to prevent unintended material outcomes during decontamination processes.
Results of previous studies
All the materials used in this study, which are summarized in table 2, were tested for their resistance to H₂O₂. Therefore, they were exposed to liquid hydrogen peroxide for up to six months and to multiple cycles of vaporized hydrogen peroxide. The studies showed no visible effect of hydrogen peroxide on these materials compared to unexposed test materials.
Furthermore, studies on the influence of cleaning agents on some of the materials listed in table 2 were performed. The results are summarized in table 1. Test material 1 (stainless steel) was exposed to cleaning agents D (Klericide Active Chlorine®) and E (Klericide Neutral Detergent®) for 20 times and showed slight rust formation at welds for D. Within in the scope of another previous study, test pieces of materials 1, 2, 3, 4, 5, and 10 (Table 2) were exposed to cleaning agents A, B, C, D, E five times for 1.5 h. For material 10, an irreversible discoloration of the bonding point at which this seal is joined to form a ring was observed. Since this is not considered to be a degradation of the actual material, it can be concluded from this study that the cleaning agents had no visible effect on the test materials.
A comprehensive study is performed to enhance the understanding of the combined impact of residual cleaning agents and vH₂O₂. This is vital for several reasons:
Material Longevity: Surfaces undergoing regular decontamination procedures must maintain their structural soundness throughout their lifespan. Synergistic effects could accelerate material deterioration, leading to increased maintenance costs and potential safety risks.
Infection Control: In healthcare settings, compromised materials could harbor pathogens and hinder infection control efforts. Properly designed decontamination protocols must not compromise surface materials' ability to resist colonization.
Regulatory Compliance: Regulatory agencies demand evidence of materials' compatibility with decontamination protocols. A detailed understanding of effects on materials is imperative to meet these standards.
A comprehensive study involving eleven materials commonly found inside barrier systems was conducted. The materials and their use in barrier systems are described in following table 1:
Table 2: Test materials, their application in FZ barrier systems and a photo of the samples.
This study exposed the test materials to a combination of residual cleaning agents and vH₂O₂ under controlled conditions. Six different cleaning agents were used, which are listed in table 3:
After being exposed to the cleaning agents for a span of 1.5 hours, the materials were subsequently introduced into a vH₂O₂ cycle within a sterility testing isolator (see Figure 1). This cycle encompassed a 36-minute gassing interval, with a total injection of 96 g of H₂O₂.
To evaluate lifetime of equipment, test pieces were exposed 20 times alternately with cleaning agents and vH₂O₂. Material properties, like surface morphology, and optical characteristics, were evaluated before the first and after each exposure according to DIN EN 13018.2016-06 . After these 20 exposures, the samples were cleaned with distilled water and a brush to remove potential residues and a final visual inspection was carried out. Exposure to distilled water instead of cleaning agents served as negative control (table 1, NC). For evaluation of the effects, all test materials were compared to test pieces not exposed to vH₂O₂ and cleaning agents.
This study was conducted to understand the effects of a combination of cleaning agents and vH₂O₂ on materials as a representative of the real situation during sterile product manufacturing. The following table 4 presents the findings of a comprehensive study focused on assessing the response of various materials to the combined exposure of cleaning agents and vaporized hydrogen peroxide (vH₂O₂).
For five combinations of materials and cleaning agents, changes of material integrity or colour were found, all other combinations did not show any effect on the material by the combination of cleaning agents and vH₂O₂. Pictures of the visible findings are displayed in following table 5:
Stainless Steel plus Klercide Active Chlorine®: When stainless steel samples were exposed to a combination of Klercide Active Chlorine and vaporized hydrogen peroxide (vH₂O₂), rust formation was observed on the cutting edges. Rust formation was also present on weld edges, indicating that uneven steel surfaces are more susceptible to rust formation caused by this cleaning agent. The rust was absent when the stainless steel samples were exposed to the cleaning agent alone less frequently in the other previous study.
Stainless steel samples treated with Klercide Neutral Detergent® and vH₂O₂ together displayed minimal rust stains. Rust stains were not apparent when stainless steel samples were exposed solely to the cleaning agent. This suggests that the combination of Klercide Neutral Detergent® and vH₂O₂ had a mitigating effect on rust formation compared to the individual components.
Silicone PACTAN material exhibited slight discoloration when subjected to both Klercide Active Chlorine® and Klercide Neutral Detergent®, indicating an adverse reaction between the material and the cleaning agents. However, data regarding the material's response to cleaning agents alone is not available, leaving room for further investigation into the sole impact of cleaning agents on this material.
HPU samples treated with Helipur® and vH₂O₂ exhibited material compromise. This outcome emphasizes the sensitivity of HPU material to this combination. Data on the reaction of the material to Helipur® alone are unfortunately not available. The reaction of HPU to Helipur® revealed major concerns for its use, this material should not be used inside barrier systems with vH₂O₂ decontamination or Helipur® should be excluded as cleaning agent.
The experimental design would lead to higher detergent residues on the material surface than would be expected during standard operational use, as the cleaning agents were just wiped away and not rinsed properly, to show possible influences within the experimental setup.
For the stainless steel samples treated with cleaning agent D (Klericide Active Chlorine®) the results are not yet clear. It seems that the surface texture has an influence on the effect of the cleaning agent. Rust was present only on welding and cutting edges. Rust was present with and without additional vH₂O₂ gassing. Therefore, there was no clear indication that the presence of vH₂O₂ increased the corrosion susceptibility of the material.
Comparative analysis with all materials subjected to cleaning agents alone would provide insights into the effects of Helipur® on HPU and Klercide Neutral Detergent® and Klercide Active Chlorine® on Silicone PACTAN. Especially for the material compromise by Helipur® on HPU further investigations are needed to determine the mechanism.
The study's results offer insight into intricate interactions between materials, residual cleaning agents, and vH₂O₂ within barrier systems. Different material responses to cleaning agents and vH₂O₂ combinations underscore the need for a comprehensive understanding to balance decontamination efficacy and material preservation.
The results of the experiments presented show that it is important to determine individual cleaning agent effects on materials and mechanisms of material compromise. By enhancing this knowledge, material and cleaning agent selection can be optimized, ensuring safety and efficacy of barrier systems and isolators in critical environments.
01. Mourya DT, Shahani HC, Yadav PD, Barde PV (2016). Use of hydrogen peroxide vapour & plasma irradiation in combination for quick decontamination of closed chambers. Indian J Med Res. 2016 Aug; 144(2): 245–249.
02. Bürkle GmbH. Chemische Beständigkeit von Kunststoffen. Version 3.12 (09.05.2022).
03. Industrial Specialties Mfg. and IS Med Specialties. Chemical Compatibility Chart. Version 27Oct2022.
04. DIN e.V. (Hrsg.) (DIN EN 13018.2016-06): Zerstörungsfreie Prüfung – Sichtprüfung – Allgemeine Grundlagen (EN 13018:2016D), Beuth-Verlag, Berlin, 2016.
We thank our colleagues from the Aseptic Processing Technologies and Workshop departments for their technical assistance.
Conflict of Interest
All authors declare that they have no conflicts of interest.
Marcel Kötter(1), Birte Scharf(2*), Marina Gole(3)
1 Franz Ziel Gmbh, Aseptic Processing Technologies
2 Franz Ziel Gmbh, Senior Scientist - GMP Compliance
3 Franz Ziel Gmbh, Head of Aseptic Processing Technologies
*Corresponding author: Birte Scharf
Franz Ziel GmbH,
Tel: +49 1520 9541090