Fall 2016 Senior Abstracts
Paper Analytical Devices to Detect Substandard Antibiotics
Sarah Bleise '17
The quality of antibiotics in the developing world is a growing concern, because poor-quality medicine can cause treatment failure, adverse drug effects, increased drug resistance, and reduce the confidence of consumers in the health care system of the society. Good quality medicines must meet pharmacopeia standards that describe the content and bioavailability of their active pharmaceutical ingredients (APIs). Medicines can fail to meet these standards for a variety of reasons including deliberate falsification, careless manufacturing, and degradation during storage. Detection of poor-quality antibiotics in low-resource settings is difficult because analytical instruments are hard to access, so I have developed a way to detect falsified or degraded ceftriaxone using a paper analytical device (PAD). These paper devices contain 12 lanes, separated by hydrophobic wax, with different reagents deposited on the lanes to detect binders, fillers, and APIs. Ceftriaxone is an injectable antibiotic used to treat life-threatening infections and is listed by the World Health Organization (WHO) as an essential medicine. The thermal degradation products have not been reported, although the products from other conditions such as acid and base hydrolysis have been studied in detail. I validated the USP method for the analysis of ceftriaxone sodium and ceftriaxone injectable samples using High Performance Liquid Chromatography (HPLC). Validation shows that the method is reliable and reproducible on our lab's HPLC instrument. Samples of ceftriaxone dissolved in sterile water were heated to simulate poor storage conditions and the rates of formation of different degradation products were tracked; the products were identified by Liquid Chromatography-Mass Spectrometry (LC-MS). I noticed four degradation products that formed throughout the study; the retention times of these products were similar to those in the literature. The sample solution failed the USP standard after six days at room temperature. In parallel with this high-tech instrumentation study, PADs were used to track the colorimetric responses during degradation. PADs were analyzed using ImageJ and coupled to true concentrations found from HPLC.
Impact of European Buckthorn On Songbird Biodiversity
Jake Kastenbauer '17
Flora and fauna within a terrestrial ecosystem affect many parameters of life on a local scale. Biotic and abiotic factors of the environment interact to form a complex framework of connections in the natural world around us. Rhamnus cathartica, an invasive shrub known as common buckthorn, plays a large role in these connections in North American woodlands. By displacing local plant life, it may decrease available inhabitable options for arthropods and songbirds, with lower plant diversity giving rise to lower animal diversity. This study examined woodland habitat points within 16 Minnesota parks. At each point vegetation, arthropod, and songbird censusing were used to assess how biodiversity and species richness of plant and animal life were affected by varying degrees of buckthorn presence. Ultimately it was shown that arthropod diversity and richness were most heavily influenced by the presence of shrub layer buckthorn, yielding greater arthropod diversity and richness when more of the shrub layer was comprised of buckthorn. Greater buckthorn presence then negatively influenced bird diversity. This may be due to greater vegetation density providing a refuge from predators such as songbirds, who rely on less densely forested areas to gain a predatory advantage.
