Parry K Rusten seems to prefer a comprehensive approach, scrutinizing both final products and the manufacturing processes to ensure that quality assurance is being upheld. He focuses on verifying both the processes used in the manufacture of sterile preparations and the products' compliance with potency limits. His interests span a range of areas, highlighting the importance he places on holistic compliance with regulatory standards.

Based on his past 483 inspections, Parry K Rusten appears to have a keen interest in the sterility process, its testing, and validation. He often emphasizes environmental control as part of the sterility assurance process. His focus is not just on the end product but also on the processes used in the manufacture of sterile preparations and whether they meet appropriate potency limits. Furthermore, Rusten shows interest in elements required for a thorough quality control and assurance program such as stability testing.