High Purity water systems are widely used in various industries for the production of purified water. This pure water serves a wide range of purposes such as drinking water systems, industrial boilers, food and beverage processing, cosmetics, pharmaceutical production, seawater desalination, and many other applications. Out of all these, water used in Pharmaceutical water systems is required to comply with stringent national and international standards. Pharmaceutical industries require pure water for the production of water for injection, clean steam and water for other parenteral and non-parenteral products. The water systems must be designed, installed, commissioned and validated with utmost care following all the appropriate steps for validation.
A high purity water system is made up of numerous small parts and processes. Hence, several factors can affect the efficiency of the ‘purity’ of water produced from the system. One of the basic factors that affect is the design of the system. While designing the pure water system, one needs to consider some key elements. The major factor touching the design of the system is the end use of the product that is to be manufactured. For example, pyrogenic contamination is a major concern while producing parenteral products. To this end, it is recommended that Water for Injection (WFI) be used for its production. This applies to the formulation of products, as well as to the final washing of components and equipment used in their manufacture. Currently, only distillation and reverse osmosis (RO) filtration are the only acceptable methods listed in the USP for producing Water for Injection. Another factor that impacts the design of the water system is the temperature of the system. Yes, hot water systems are expensive. However, they are self-sanitizing and require significantly less maintenance. As such, other water systems create require extensive testing and have a greater potential for problems while operation.
The temperature is also a relevant factor when the water is in constant motion. A one-way water system is basically a “dead-leg” which means that water stays in the dead part of the water system and increases chances of contamination. Finally, and most possibly the most important consideration is the risk assessment or level of purity that is desired. Different products require different levels of purity in water. Parenteral products require very pure water with no endotoxins, topical and oral products require less pure water with no requirement for endotoxins. We have talked about the factors affecting the design of a high purity water system. After we have designed and installed a pure water system, we need to make sure that we validate the system’s design with the actual performance. Validation is an important step in the setting up of a pure water system. It provides a stamp of approval to the water system that it is producing the right quality of pure water required for the manufacture of the pharmaceutical product. The initial phase of water system validation involves developing the operational parameters and the cleaning/sanitizing procedures and frequencies. After each step in the purification process, sampling should be done and these samples need to be drawn daily at each point of use for two to four weeks. At the end of the two to four week time period, the firm should have developed its SOPs for the operation of the water system. The second phase of the system validation involves demonstrating the system will consistently produce the desired quality of pure water. The sampling is the same as performed in the initial phase. This phase should be able to produce the data that proves the water systems’ capability to consistently produce the intended quality of pure water.
The third and final phase of the water system validation is designed to collect data and demonstrate that when the water system is operated per the SOPs over a long period it will consistently produce desired purity of water. This phase also intends to pick up on any variations in the quality of the feed water that could affect the operation and the water quality. Routine procedures and frequencies are followed for the sampling of the water produced from the system. The last part is the compilation of data, with any conclusions and remarks in the final report. The final validation report is signed by the appropriate people responsible for the operation and quality assurance of the water system.