FDA STERILITY DRAFT GUIDE RECOMMENDS "STERILE MEDIA FILL" TECHNIQUE TO VALIDATE ASEPTIC ASSEMBLY PROCESS; VALIDATION, LAB CONTROLS, STERILITY TESTS ADDRESSED

FDA's newly released draft guideline on sterile drug products produced by aseptic processing recommends the use of "sterile media fills" to validate the assembly process. The guideline defines "sterile media fills" as microbiological growth nutrient media used to simulate sterile product filling operations. According to the draft guide, "media filling in conjunction with comprehensive environmental monitoring can be particularly valuable in validating the aseptic processing of sterile solutions and suspension." In general, the guide notes, validating the aseptic assembly of sterile product elements, i.e., filling/sealing, has generated more questions from industry than has the sterilization of those elements, and "therefore, the guidance presented places greater emphasis on validating the aseptic assembly operations." Questions raised by industry about media fills and addressed in the guideline concern contaminating equipment with media, frequency and number of runs, size of runs, the media itself, environmental conditions, and test results. FDA considers the aseptic processing guide to be a priority guideline due to the frequency of compliance problems in the area, the degree of unfamiliarity in the industry with FDA expectations, and the lack of uniformity between firms in their sterile practices. The agency explains that the guideline is not intended to cover all aspects of sterile processing but to address those areas that have been most problematic for industry. Selected current good manufacturing practice requirements are cited, followed by a discussion of practices and procedures which FDA considers as acceptable means of meeting the requirement. The guide discusses buildings and facilities, components, containers/closures, production time limitations, validation, laboratory controls, and sterility testing. Guide Stresses Importance Of Specifying Criteria For Conducting Investigations Of Sterility Failure Another aspect of aseptic processing that the guideline addresses at some length is drug product sterility testing. Aspects of the sterility testing which the guideline states "are of particular importance" and discusses include control of the testing environment, understanding the test limitations, interpretation of positive results, and retesting. The guideline emphasizes the importance of having written procedures in place to specify the criteria for conducting investigations of sterility failures, including decision rules for rejecting batches. Firms should lean toward the side of safety and reject batches if the investigation of positive testing results shows a production failure. A retest is warranted, the guide states, only if each of three conditions is met: "The organism found in the test is not found in the production area or the bioburden, but has been shown to occur in the testing area; the incidence of growth in test units is not greater than the laboratory's record of false positives over a period of time; and batch production and control records show no discrepancies which could affect sterility." Aspects of asceptic processing not addressed in the draft document include employee hygiene, aseptic gowning, and clean room design. However, FDA said that "these and other apsects will be covered in future revisions of this guideline as needed." The guideline also does not address terminally sterilized drug products, although some portions may be applicable to their preparation, FDA noted. The Feb. 1 Federal Register notice of availability of the draft guide requests that comments be submitted by May 2, 1985. The draft is available from, and comments should be submitted to the Dockets management Branch, FDA, Rm. 4-62, 5600 Fishers Lane, Rockville, MD 20857.