WATER FOR INJECTION IN DEVICE MANUFACTURE.

Refinements in water-purity standards, together with increasingly sensitive analytical techniques and highly specialized needs, have placed a growing burden on water-purification systems. As an example, FDA (Food and Drug Administration) licensing of the Limulus amebocyte lysate assay for medical device applications has moved the threshold of pyrogen detectability from 0. 55-3. 50 ng/ml/kg of body weight (USP pyrogen test) to 0. 01-0. 41 ng/ml, representing at least a tenfold increase in sensitivity. In the same manner, capillary-method gas chromatography, mass spectrometry, and reversed-phase high-performance liquid chromatography have given users the ability to isolate and identify organic substances at parts-pertrillion concentrations. Although the commonly used purification systems can easily meet current WFI (Water For Injection) requirements, increasing demands for higher-quality, economically produced water will necessitate that new techniques be examined. Current trends point toward a diversification of the purified-water system to include more types of methods, especially in the highly complex area of device manufacture.