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Full-Text Articles in Medicine and Health Sciences
Sex Differences In The Kinetic Profiles Of D- And L- Methylphenidate In The Brains Of Adult Rats, J. Bentley, F. Snyder, Stacy D. Brown, R. W. Brown, Brooks B. Pond
Sex Differences In The Kinetic Profiles Of D- And L- Methylphenidate In The Brains Of Adult Rats, J. Bentley, F. Snyder, Stacy D. Brown, R. W. Brown, Brooks B. Pond
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OBJECTIVE: Methylphenidate is commonly used in the treatment of Attention Deficit Hyperactivity Disorder and narcolepsy. Methylphenidate is administered as a racemic mixture of the d- and l- threo enantiomers; however, the d-enantiomer is primarily responsible for the pharmacologic activity. Previous studies of the behavioral effects of methylphenidate have highlighted sex differences in the responsiveness to the drug, namely an increased sensitivity of females to its stimulatory effects. These differences may be due to differences in the uptake, distribution, and elimination of methylphenidate from male and female brains. Therefore, we compared the pharmacokinetics of d- and l- threo methylphenidate in the …
Random Mutagenesis Of The Aspergillus Oryzae Genome Results In Fungal Antibacterial Activity, Cory A. Leonard, Stacy D. Brown, James Russell Hayman
Random Mutagenesis Of The Aspergillus Oryzae Genome Results In Fungal Antibacterial Activity, Cory A. Leonard, Stacy D. Brown, James Russell Hayman
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Multidrug-resistant bacteria cause severe infections in hospitals and communities. Development of new drugs to combat resistant microorganisms is needed. Natural products of microbial origin are the source of most currently available antibiotics. We hypothesized that random mutagenesis of Aspergillus oryzae would result in secretion of antibacterial compounds. To address this hypothesis, we developed a screen to identify individual A. oryzae mutants that inhibit the growth of Methicillin-resistant Staphylococcus aureus (MRSA) in vitro. To randomly generate A. oryzae mutant strains, spores were treated with ethyl methanesulfonate (EMS). Over 3000 EMS-treated A. oryzae cultures were tested in the screen, and one isolate, …
Stability Of Extemporaneously Prepared Lansoprazole Suspension At Two Temperatures, Jordan T. Morrison, Ralph A. Lugo, Jim C. Thigpen, Stacy D. Brown
Stability Of Extemporaneously Prepared Lansoprazole Suspension At Two Temperatures, Jordan T. Morrison, Ralph A. Lugo, Jim C. Thigpen, Stacy D. Brown
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OBJECTIVE The purpose of this study was to examine the stability of a generic lansoprazole product in a 3 mg/mL sodium bicarbonate suspension under room temperature and refrigerated conditions. METHODS Lansoprazole suspensions (3 mg/mL) were prepared in triplicate using an 8.4% sodium bicarbonate vehicle for each storage condition (room temperature and refrigerated). During 1 month, samples from each replicate were periodically removed and analyzed for lansoprazole concentration by liquid chromatography–tandem mass spectrometry (LC-MS/MS). Each sample was spiked with 10 mg/L omeprazole to serve as the internal standard. A positive electrospray LC-MS/MS method was validated over the calibration range of 5 …
The Fate Of Sulfamethazine In Sodium-Hypochlorite-Treated Drinking Water: Monitoring By Lc-Msn-It-Tof, Tyler C. Melton, Stacy D. Brown
The Fate Of Sulfamethazine In Sodium-Hypochlorite-Treated Drinking Water: Monitoring By Lc-Msn-It-Tof, Tyler C. Melton, Stacy D. Brown
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Pharmaceutical compounds represent a rapidly emerging class of environmental contaminants. Such compounds were recently classified by the U.S. Geological Survey, including several antibiotics. An LC-MS/MS screening method for the top five antibiotics in drinking water was developed and validated using a Shimadzu LC-MS-IT-TOF. The separation was performed using a Waters Acquity UPLC BEH C18 column with a gradient elution. Sulfamethazine was exposed to conditions intended to mimic drinking water chlorination, and samples were collected and quenched with excess sodium sulfite. Kinetics of sulfamethazine degradation was followed as well as the formation of the major chlorinated byproduct (m/z 313). For the …
Quantification Of Lansoprazole In Oral Suspension By Ultra-High-Performance Liquid Chromatography Hybrid Ion-Trap Time-Of-Flight Mass Spectrometry, Stacy D. Brown, Justin D. Connor, Nicholas C. Smallwood, Ralph A. Lugo
Quantification Of Lansoprazole In Oral Suspension By Ultra-High-Performance Liquid Chromatography Hybrid Ion-Trap Time-Of-Flight Mass Spectrometry, Stacy D. Brown, Justin D. Connor, Nicholas C. Smallwood, Ralph A. Lugo
ETSU Faculty Works
An LC-MS/MS method was developed and validated to be used as a stability indicating assay for the study of a 3 mg/mL lansoprazole oral suspension. The method utilizes a UPLC (ultra-performance liquid chromatography) column and unique mass spectrometric detection (ion-trap time-of-flight (IT-TOF)) to achieve a sensitive (LOD 2 ng/mL), accurate, and reproducible quantification of lansoprazole. This method reports an intraday and interday coefficient of variation of 2.98 ± 2.17% ( for each concentration for each day) and 3.07 ± 0.89% ( for each concentration), respectively. Calibration curves (5–25 μg/mL) were found to be linear with an value ranging from …