Issue link: https://www.e-digitaleditions.com/i/997634
6 BioPharm International eBook June 2018 www.biopharminternational.com Single-Use Systems Materials which stems from the desire to have more universal solutions or configurable systems that can be assembled like building blocks. Secondly, the biopharma indus- try is challenging SUS integrators a nd t heir component suppliers to generate more sta nda rd i zed data, based on indust r y- d r iven protocols. The objective in stan- dardizing protocols and enforc- ing stricter testing by component suppliers is to ensure better com- p a r a b i l it y a nd ac c e le r ate r i sk assessment analysis. Specifically, this includes more relevant stan- d a rd s, wh ic h a re desig ne d for single-use systems and compo - nent s, to test for pa r t ic u lates, extractables, and physical system i nteg r it y. A S T M I nter nat iona l, U S P [ t h e U S P h a r m a c o p e i a l C o n v e n t i o n ] , a n d B P E [ t h e American Society of Mechanical E n g i n e e r s : B i o p r o c e s s i n g Equipment] are working on new standards and updates to existing chapters. In add it ion, a joint tea m of s u b j e c t- m a t t e r e x p e r t s f r o m BioPhor u m O p e r at ion s Group (BPOG) and Bio-Process Systems A l l ia nce ( BP SA) is work i ng on the development of a SUS user- requirement specification (SUURS) to ol k it t hat w i l l s upp or t SUS design, qualification, and com- munication of the requirements between suppliers and end-users. These new guidelines will help the implementation of the single-use components into the drug manu- facturers' operations. SILICONE FOR TUBING AND ASSEMBLIES BioPharm: What are the advantages (and disadvantages) of silicone as a material for tubing compared to other polymers used for tub- ing in biopharma manufacturing processes? Kollar and Mathis (Dow): Because tubing represents one of the larg- est surface areas in direct contact with drug substances during the drug manufacturing process, tub- ing and molded assemblies need to meet strict regulatory and quality requirements. Silicone offers high purity and safe solutions resulting from the cleanliness and biocom- patibility of the silicone formula- tions used to produce the tubing and molded assemblies products and Dow's full vertical integration across the supply chain provide strict manufacturing control for Dow's products. The silicone elastomers used to make silicone tubing are composed of a silicone base (polydimethyl siloxane polymers and reinforcing filler), a silicone cross-linker, an inhibitor, and a catalyst (at very low level). Consequently, silicone elastomers possess low and predict- able extractables profile, which prevent contamination of the drug during its manufacturing process. In contrast, plasticizers and other additives are often added to ther- moplastic tubing formulations. Furthermore, silicone materi- als are inherently biocompatible and inert, therefore they have no adverse effect on human health, and they are not sensitizing, not pyrogenic, not genotoxic, not cyto- toxic, and not hemolytic. They also exceed United States Pharmacopeia (USP) <88> Class VI tests. Additional advantages of sili- cone tubing include its flexibility, transparency, and ease of steriliza- tion. Moreover, silicones are cat- egorized as thermoset materials: they are stable under a wide range of temperatures from -80 °C to at least +215 °C. On the other hand, they cannot be sealed or welded, requir ing ster ile connec tors or overmolding to connect tubing sections together. We help our cus- tomers overcome this challenge by supplying both pharma tubing and molded assemblies and offer- ing technical service and applica- tion support. EXTRACTABLES AND LEACHABLES BioPharm: What are the extract- a b l e s / l e a c h a b l e s c o n c e r n s o r possible interactions with biophar- maceuticals with silicone materials? Kollar and Mathis (Dow): In sili- cones, extractables are low levels of low molecular weight oligomers originating from the silicone poly- mers. The extrusion process and manufacturing environment also influence the extractable profile of the end-product. Expertise of both material science and process can improve extractable levels. Extractables and leachables con- cerns apply mostly to process con- tact materials (PCM) components especially in the downstream part of the biopharma process after the filtration step. Tubing and bags are among the largest surface com- ponents in contact with the final drug and should demonstrate a low extractable profile. The concern over extractables is not specific to silicone materi- als, and silicones offer one of the cleanest purity profiles compared w it h most t her moplast ics. T he concern has been increasing with the use of non-silicone materials like polyvinyl chloride and other t he r mopla st ic s. T he up st r e a m value chain for these materials is more fragmented and thus offers le ss cont rol, t r ac e abi l it y, a nd healthcare regulatory compliance. The extractables profile of plat- inum-cured silicones are simple and predictable because there are no organic additives introduced into the formulation and there is no by-product formed during the curing reaction. Cases where silicone materials should not be