Quality-control analytical methods: aqua pura: water purification systems and United States pharmacopeia waters for the compounding pharmacy, part 1.

The types of water used most often in a compounding pharmacy are potable water, purified water, and sterile water (water for injection or irrigation). Of those three types, purified water is most frequently used; it is essential as a clean glassware rinse and is used in the compounding and reconstitution of frequently prescribed no sterile compounds, such as antibiotic suspensions. Using the appropriate water is absolutely essential to good compounding practice. Purified water cannot be substituted for sterile water for irrigation or injection, and if the last step in washing glassware and pharmaceutical implements is not a thorough purified-water rinse, the cross-contamination of preparations with drugs or chemicals (the presence of which can be missed even during potency testing) can occur. In this first of a series of three articles, we briefly review the types of United States Pharmacopeia water used most frequently in compounding, discuss the basic types of water purification systems that can be used in a compounding, discuss the basic types of water purification systems that can be used in a compounding pharmacy, and answer questions about water purification systems that are of interest to compounding pharmacists. Part 2 will provide current information from the United States Pharmacopeia about various waters, and part 3 will present testimonials from compounders who are using an in-house water purification system and additional information about water purification systems from manufacturers or vendors of that equipment (a Table comparing various water purification systems will be included for easy reference).