2.2.1 BackgroundExtracting water fr

2.2.1 BackgroundExtracting water from a system into a container for subsequent laboratory analysis is the most common sampling utilized by pharmaceutical companies to determine the levels of CQAs. This testing methodology is also the most frequently used method for determining the microbiological and endotoxin content of water. As the accuracy and reliability of instrumentation has increased, establishing the equivalency between the conventional “sample and laboratory test” method and the “continuous monitoring with an instrument” method may allow an increasing number of CQAs to be verified continuously. This can substantially reduce the frequency of water sampling from a system.In order to determine if an attribute is a candidate for monitoring with process instrumentation, the uniformity of distribution of the attribute within a water system needs to be understood.In pharmaceutical water systems, CQAs or other impurities may or may not be uniformly distributed in a distribution system. The homogeneous or heterogeneous nature of distribution of CQAs in a system should be understood prior to formulating a sampling plan.