More industry users of rapid methods are publishing their assessment and validation studies in scientific journals. In the May-June issue of the PDA Journal of Pharmaceutical Science and Technology, two excellent papers were presented on endotoxin and sterility testing. Their references and abstracts are below.
2010. Luis Jimenez, Narendra Rana, Kasey Travers, Verce Tolomanoska, and Kimberly Walker. Evaluation of the Endosafe® Portable Testing System™ for the Rapid Analysis of Biopharmaceutical Samples. PDA J Pharm Sci Technol. 64:211-221.
The Endosafe® Portable Testing System™ (PTS™) portable system for endotoxin testing was evaluated to analyze biopharmaceutical samples such as raw materials and finished products. The installation, operational, and performance qualification procedures were successfully implemented and verified to determine the system functionality under good manufacturing practices. During the validation stages the PTS™ was compared to the gel-clot test method in terms of presence or absence of endotoxin substances, ease of use, completion time, resource optimization, and sample volume. Water for injection and product samples were analyzed with both methods. All water for injection and product samples were negative for the presence of endotoxin by both methods. However, PTS™ results were obtained after 15 min while the gel-clot completion time was 1 h. Miniaturization of endotoxin testing by the PTS™ allowed optimization of testing procedures by reducing sample volume, analyst manipulations, accessory materials, and turnover time, and by minimizing the risk of exogenous contamination of the reaction.
2010. Jennifer Claire Gray, Alexandra Staerk, Manfred Berchtold, Werner Hecker, Gunther Neuhaus, Andreas Wirth. Growth-promoting Properties of Different Solid Nutrient Media Evaluated with Stressed and Unstressed Micro-organisms: Prestudy for the Validation of a Rapid Sterility Test. PDA J Pharm Sci Technol. 64:249-263.
Currently, sterility testing in the pharmaceutical industry—a mandatory release test for all sterile drug products—takes an incubation time of at least 14 days and is based on liquid media according to the pharmacopoeias. The search is on for a rapid sterility test to reduce this rather long time frame. For this we have chosen the Millipore Milliflex Rapid Microbiology Detection System, which is based on solid nutrient media. As a prerequisite for the validation of this rapid sterility test, a solid nutrient medium promoting the growth of stressed and unstressed micro-organisms replacing tryptic soy broth and fluid thioglycollate medium from the traditional sterility test had to be found.
For this a wide variety of appropriate nutrient media were evaluated. After a prestudy with 10 different nutrient agar media, tryptic soy agar, Center for Disease Control (CDC) anaerobic blood agar, Schaedler blood agar, and Difco brewer anaerobic agar were tested in detail using a range of 22 micro-organisms (7 ATCC strains and 15 production site-specific strains). These strains were inoculated in their unstressed and in a stressed state. Stress was evoked by heat treatment and nutrient starvation in the case of the sporulating bacteria. This stress effect—resulting in deceleration in growth—was experimentally confirmed based on growth curve analysis. It was statistically evaluated which media and which incubation temperatures are best suitable.
The resulting data showed that Schaedler blood agar has the best growth-promoting properties among the agars tested and is going to be used in the rapid sterility test with the incubation temperatures 20–25 °C for aerobes, 30–35 °C for aerobes, and also 30–35 °C for anaerobic micro-organisms.