How Advanced Single-Use Polymeric Materials Influence Extractables Testing

Implementation of single-use systems in both upstream and downstream applications continues to grow rapidly. Parallel to that growth is the concern about purity levels of polymeric single-use systems because compounds found in disposable materials of construction can leach into process fluids or final drug products. By definition, extractables studies are intended to identify chemical substances that could migrate into process fluids. These tests generally take place under exaggerated conditions that exceed those typically found in bioprocess manufacturing or storage. Industry organizations such as the Bio-Process Systems Alliance (BPSA), the American Society of Mechanical Engineers–Bioprocessing Equipment (ASME BPE), and the BioPhorum Operations Group (BPOG) have established extractables testing guidelines and protocols that can be categorized as either material-specific or bioprocess-specific worst-case testing. The actual protocol used in an extractables evaluation is often determined according to the intended use of the results (why testing is being performed and what decisions will be made based on the resulting data). Test results may be needed for an initial material screening or used for comparison of materials or competitive products. These studies can also be used as a quality control method or as a substitution for leachable testing. Another factor that affects extractable testing protocol decisions is technological progress in polymers used in single-use applications. During the early adoption period of single-use systems, the polymers used as materials of construction were typically commodity polymers. They serviced multiple applications across multiple industries. Unfortunately, the amounts used in bioprocessing applications were quite small, and the industry was forced to settle with nonapplicationspecific materials. Fortunately, the implementation of single-use systems (SUS) has increased to a point at which demand for better polymer performance has grown, suppliers are moving toward advanced polymeric materials. Such materials can be formulated and controlled specifically for the needs of bioprocessing, or they can be adopted from other hightechnology industries with similar needs for high purity and performance.