Minimize The Impact Of Hydrogen Peroxide On Biopharmaceuticals With The Right Analysis

Thanks to the advancement of science and technology, the biomedical industry has made breakthroughs in recent years. Biologics are now widely used in the treatment of cancer, autoimmune diseases, and small groups of rare diseases. However, these highly effective and even highly toxic drugs require special safety precautions and fully enclosed production conditions during production to provide adequate safety protection for staff and drugs; in addition, newly developed biological drugs are usually produced in small batches. The way of production also requires a high degree of flexibility and modularity. Therefore, in order to flexibly integrate the isolator into existing workshops and clean rooms while ensuring the safety of the production process, it is essential to adopt an integrated air treatment system and an optimized biological purification process.

Part 1 H2O2—Coexistence Of Safety And Risk Factors

Decontamination with hydrogen peroxide (H2O2) gas has become standard for automatic biodecontamination of isolators. At normal temperature, H2O2 is a fairly stable liquid compound, a strong oxidant, especially suitable for biological purification due to its broad-spectrum effect. H2O2 gas is used for purification. After the cycle is over, the remaining H2O2 will be replaced from the isolator through catalyst decomposition or rapid ventilation through fresh air, so that the residual concentration in the isolator is acceptable. But the rapid development of the biotechnology industry has further increased the requirements for filling equipment and isolators, because many biopharmaceuticals are very sensitive to H2O2. The new requirement is to keep the H2O2 concentration in the isolator below 0.5 ppm (0.5 parts per million) before filling begins. However, the exact limit depends largely on the product’s sensitivity to H2O2, and some products may require much lower requirements, even as low as about 0.03 ppm. Although the isolators are vigorously purged after the purge cycle, some H2O2 will still remain in them and may even condense on the inside of the isolators or on the surfaces of the filling equipment. Once H2O2 enters the liquid drug, it may cause oxidation of the drug. While the residual concentration of H2O2 in standard isolators can be reduced to 0.5 ppm after 1 hour of air purge, it may take several hours to reach it (0.03 ppm) for particularly sensitive biopharmaceutical products. This requires that the downtime of the filling line be kept as short as possible, especially in small batch applications with frequent product changes and/or long-term continuous production.

Part 2 Taking Biological Therapy As An Example

Biomolecules such as hormones or antibodies are easily oxidized. Modifications to sensitive amino acid residues such as methionine, tryptophan, and cysteine can affect their physicochemical properties and possibly their protein secondary and tertiary structure, thereby affecting the efficacy and/or safety of the product potential impact. Sensitivity of medicinal products depends on many factors, such as the individual properties of the active ingredient, the type, number and location of oxidizable amino acid residues, and their specific effects on pharmacodynamics and/or pharmacokinetics. Formulation-related parameters, such as the concentration of active ingredients and the presence of oxidation-sensitive or antioxidant excipients (e.g. polysorbate, L-methionine), also have an impact on drug product susceptibility. In addition, the diameter of the container and especially the (effective) size of its opening also affects the diffusion of H2O2 in the product solution. In addition to these product-related factors, the filling equipment, technology and process itself also play an important role. If the product is filled, shut down or filled before entering the freeze dryer, it will stay in the buffer area of the isolator. At this time, the product will be opened or partially plugged, and it will be exposed to the residual H2O2. The length of exposure time may vary. It has an impact on pharmaceuticals, so companies need to pay close attention to this; in addition, during the interruption of the production line, the silicone tube will absorb and slowly release H2O2, which may cause H2O2 to enter the product solution; and during the filling process, nitrogen filling Covering the container can help reduce residual H2O2 in the container.

Part 3 Analysis Is The Key

What conditions need to be considered when using H2O2 purification? At first sight it seems reasonable to define a common standard in terms of the most sensitive products. Depending on the exposure, residual levels of 0.03 ppm may have affected some molecules. Without experience producing such products, pharmaceutical companies often choose to use levels far lower than required to ensure safety. However this means longer air change times, which wastes time and limits the availability of the system. A better and more efficient solution is to analyze the most important parameters. How does the product react with H2O2? What is the maximum allowable residual concentration to avoid the risk of oxidation? Unfortunately, at the moment we are still only able to continuously monitor the “in-air” concentration by means of an online measurement system during the bio-decontamination, ventilation/ventilation and production phases. Furthermore, sensors used for routine monitoring typically have a sensitivity of only 0.1 ppm, which is insufficient for particularly sensitive products. It is now necessary to verify the purge and gas exchange cycles with special and very sensitive sensors used on non-conventional production equipment.

Part 4 Many Factors Affect The Residual Concentration

On the other hand, the concentration of H2O2 in the product solution is difficult to track during production and can only be determined by off-line experiments. However, we can experimentally determine the relationship between the concentration of H2O2 in the air and the concentration of H2O2 in solution. By keeping the concentration of H2O2 in the air constant and only changing the exposure time of the product or substitute, it is possible to determine its absorption law and simulate the conditions on the production line. Based on this data, pharmaceutical companies and equipment suppliers can fine-tune the bio-decontamination process of existing production lines. For new production lines, extensive product knowledge helps to adapt isolators to specific requirements more precisely.

– We can experiment to determine the relationship between the concentration of H2O2 in the air and the concentration of H2O2 in the solution –

When designing or optimizing an isolator, it is important to understand all relevant product, process and equipment parameters. Once an acceptable H2O2 concentration has been determined for a specific product and process, the pharmaceutical industry should know that this limit cannot be exceeded in a qualified and validated purification process. In addition, many factors from the type of container and its filling volume, the temperature in the isolator, the air volume and the change of H2O2 concentration over time, as well as the duration of the process and the exposure time of the stopper and the container will have an impact on the residual concentration of H2O2 . There is also optimization potential for the materials used on the filling equipment and isolators. For example, materials such as silicone tubing or seals will absorb H2O2, they will release H2O2 very slowly, so if you are handling very sensitive products, the use of such materials should be kept to a minimum.

Part 5 Conducts Detailed Research

Ideally, exposure of products to H2O2-containing air would be simulated in a test isolator where open-ended products could be exposed to defined concentrations of H2O2 for varying lengths of time, but this is not achievable for every development lab . In addition, various process parameters can be considered, such as the time between filling and stoppering, line interruption times due to interventions, and buffer times when partially stoppered containers are loaded in the lyophilizer. However, due to several handling issues (mainly the need for manual sample preparation), such studies often fail to generate sufficient samples for subsequent stability studies.

Part 6 Experience Creates Ideal Craftsmanship

Despite the high sensitivity of certain biopharmaceuticals, H2O2 is still the first choice for isolator decontamination. With experience and proper research, it is possible to determine with great precision how to design and operate a specific filling line to achieve safe and effective decontamination. Especially for new production lines, purification, product oxidation, and allowable residual H2O2 concentrations should be considered during the design and engineering stages to minimize their impact on cycle time.