Rapid quantification of the aminoglycoside arbekacin in serum using high performance liquid chromatography-tandem mass spectrometry.

BACKGROUND: This project entails the development and validation of a method for quantification of the aminoglycoside antibiotic arbekacin in serum using liquid chromatography tandem mass spectrometry (LC-MS/MS) for therapeutic drug monitoring in future clinical trials. METHODS: Following a protein precipitation with 0.3 mol/l perchloric acid containing internal standard dibekacin at a concentration of 0.6 µg/ml, human serum samples containing arbekacin were analyzed using a Hypersil Gold PFP column and a liquid chromatography system. Elution occurred with a gradient of water and acetonitrile, each containing 0.05% (v/v) trifluoroacetic acid and 0.1% (v/v) formic acid. Analytes were detected over a 3.25 minute run time using a tandem mass spectrometer with a heated electrospray-ionization (HESI) source in positive ionization mode with selected reaction monitoring (SRM). Matrix effects, carryover, linearity, recovery, precision, and limit of quantification were carefully evaluated. RESULTS: The limit of quantification for arbekacin was 0.1 µg/ml. All simple and total precision CV's were less than 6.2%. The method was linear from 0.1 µg/ml to 45.9 µg/ml (slope of 0.973). The mean recovery ranged from 94.7 to 103.8%. No matrix effects were detected. CONCLUSIONS: This developed and validated LC-MS/MS method allows for the quantification of arbekacin in serum following protein precipitation.

Addition of epidermal growth factor improves the rate of sulfur mustard wound healing in an in vitro model.

OBJECTIVE: Sulfur mustard (SM) causes blisters on the human skin. These blisters delay healing of the skin and make the victims more susceptible to infection. In vitro models have been used for protection studies against SM injury, but study on wound healing after SM exposure has not been explored. The purpose of this study was to test whether the addition of exogenous growth factors could improve the rate of SM wound healing. METHODS: The model consisted of normal human epidermal keratinocytes seeded into 6-well plates, exposed to SM, and wounded (disruption of the cell monolayer) with a sterile wounding instrument. Cells were then stained and images were captured to measure percentage wound fill. Epidermal growth factor (EGF) and keratinocyte growth factor (KGF) were tested in this model. RESULTS: EGF (1 ng/mL) significantly increased wound fill on all of the days tested (days 6, 9, and 12). KGF did not significantly improve wound healing. CONCLUSIONS: EGF showed promise as a potential therapy for SM-induced wounds. This in vitro model was a valuable tool for screening therapeutics before animal testing. These results will be used to develop a dressing that can slowly release EGF on to a debrided wound bed to help speed the healing process.