Abstract
This paper proposes a method to prove that working drug manufacturing computerized systems using Programmable Logic Controller (PLC) have adequate functions and performance. Drug companies are required to prove the adequacy of functions and performance by regulatory authorities, because these systems make significant impacts for the drug quality. Especially, tasks that adequacy of working system is proved by existing documents and operational records are called Retrospective Computerized System Validation (RCSV). But no description about RCSV procedures using PLC exists. This makes the drug companies to confuse. Therefore we propose RCSV procedures that can be conducted adequately and efficiently. As a result of trials, we can confirm that the quality and efficiency of RCSV is improved.
