The choice between isolators and alternative barrier technologies in the context of Annex 1 depends on various factors, including the type of manufacturing, the product and the specific risks of the process. The choice proves to be a crucial step for pharmaceutical manufacturers to ensure the highest quality standards. Various factors play a central role in this decision. Isolators, as an established barrier technology, provide a physical separation between the manufacturing process and the external environment. Their closed system enables comprehensive control over the process, which is particularly important in the production of sterile drugs. Isolators efficiently integrate multiple process steps and provide a flexible platform for complex manufacturing processes. When making a decision, the specific requirements of the product and the manufacturing process should be carefully considered. Products with particularly high sterility requirements could benefit from the comprehensive barrier of an isolator. On the other hand, alternative technologies may be effective in processes with less complex requirements and may be more cost effective.