Antimicrobial Resources for Disinfection of Potable Water Systems for Future Spacecraft

As human exploration adventures beyond low earth orbit, life support systems will require more innovation and research to become self-sustaining and durable. One major concern about future space travel is the ability to store and decontaminate water for consumption and hygiene. This project explores materials and technologies for possible use in future water systems without requiring point-of-use (POU) filtering or chemical additives such as iodine or silver that require multiple doses to remain effective. This experimentation tested the efficacy of a variety of antimicrobial materials against biofilm formation in a high shear CDC Biofilm Reactor (CBR) and some materials in a low shear Drip Flow Reactor (DFR) which(also utilizes ultra violet light emitting diodes (UVLEDs) as an antimicrobial resource. Most materials were tested in the CBR using the ASTM E 2562-07 1method involving the Pseudomonas aeruginosa and coupon samples that vary in their antimicrobial coatings and surface layer topographies. In a controlled environmental chamber (CEC), the CBR underwent a batch phase, continuous flow phase (CFP), and a harvest before analysis. The DFR portion of this experimentation was performed in order to assess the antimicrobial capabilities of ultraviolet-A LEDs (UV-A) in potable water systems. The ASTM E 2647-08 was modified in order to incorporate UV-A LEDs and to operate as a closed, re-circulating system. The modified DFR apparatus that was utilized contains 4 separate channels each of which contain 2 UV-A LEDs (1 chamber is masked off to serve as a control) and each channel is equipped with its own reservoir and peristaltic pump head. The 10 DFR runs discussed in this report include 4 initial experimental runs that contained blank microscope slides to test the UVA LEDs alone, 2 that incorporated solid silver coupons, 2 that utilized titanium dioxide (Ti02) coupons as a photocatalyst, and 2 runs that utilized silver coated acrylic slides. Both the CBR and DFR experiments were analyzed for microbial content via heterotrophic plate counts (HPC) and acridine orange direct counts (AODC). Ofthe materials used in the CBR, only two materials performed as anti~icrobials under high shear conditions (a reduction of 5 or more logs) showing a>7 log reduction in viable microbes

A green approach for the quantification of daptomycin in pharmaceutical formulation by UV spectrophotometry

abstract Daptomycin is the first approved drug from a new class of antimicrobials, the cyclic lipopeptides, and is a very important antimicrobial agent in current clinical practice. Currently, there are no "green" analytical methods described in the literature to analyze the typical pharmaceutical dosage form of daptomycin. Thus, the aim of this work was to validate an environment-friendly spectrophotometric method in the UV region, for the analysis of daptomycin as a lyophilized powder. Water was used as diluent and the analyses were carried out on a spectrophotometer at 221 nm. The method met all validation requirements of the ICH guidelines, over a concentration range of 6-21 µg mL-1. A Student's t-test demonstrated that the proposed method was comparable to an HPLC method previously validated. Thus, the validated spectrophotometric method could quantify daptomycin in a powder form for injectable solutions, while being an economical, rapid, and "green" alternative for routine analysis in quality control