Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0016382 (flushing)
 6,387 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Elevated drug concentration (DC) can be caused by intentional or iatrogenic overdoses and sampling technique errors. This study examined, in vitro, technique factors that can cause and prevent false elevations of DCs when drugs are administered through the catheter lines from which blood samples are later taken for DC analysis. Digoxin, aminophylline, and phenytoin were administered through central catheters in concentrations simulating those used clinically. Drug solution remained in the lumen for a time similar to that encountered clinically, then either remained in the tubing or was flushed out with 5 ml of normal saline (NS). After 6 h, a 5-ml sample was withdrawn for DC analysis (the tip of the catheter placed in NS, which represented blood supply). Prior to final sample withdrawal, 5 ml of NS was drawn through half of the lines and discarded to simulate methods used to prevent contamination. Thus, various flushing/no flushing and sample discarding/no discarding techniques were analyzed. When diluted concentrations of drug were administered, minor artifactual DCs were observed unless the line was not flushed or sample fluid discarded prior to final sampling. With undiluted drug administration, only flushing after the dose and discarding a sample prior to final sampling prevented artifactual DCs. Clinicians should be aware of the potential for such artifactual elevations of DCs and should encourage techniques that prevent their occurrence.
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PMID:Effect of monitoring drug concentrations through lines used to administer the drugs: an in vitro study. 195 38

The nature of immune reactors allows development of quantitative analytical methods that are highly selective and can often be used directly with complex biological matrixes such as blood, plasma or urine. A major limitation of immunoassay is that antibodies are sometimes unable to discriminate structurally similar species such as drug metabolites and synthetic analogs. The problem associated with the lack of discrimination can be circumvented by coupling immunoassay with liquid chromatography post-column. The most commonly used separation method in post-column immunoreaction detection is the affinity column. Affinity columns may create undesired effects such as a compromise of the chromatographic separation efficiency, the requirement for an antibody with fast reaction kinetics and the need for flushing the column. This paper reports a post-column immunoreaction detection system coupled with a laboratory-constructed on-line magnetic separation flow chamber that is designed to overcome these problems. The system uses disposable magnetic beads as a solid-phase support for separation that can be easily removed from the system. The model analytes chosen for this study were digoxin and its metabolites due to the commercial availability of monoclonal antibodies for these compounds. Digoxin was separated using a chromatographic method prior to being interfaced through a liquid handler system to the immunoreactor. Compatibility of the HPLC mobile phase was determined to be acceptable with a mixing ratio of 1:3 between the LC fraction and immunoreagent solution. The dynamic range of the calibration curve in digoxin-spiked phosphate buffer was found to be 0.25-12 ng/ml and a quadratic fit was found to provide the best fit to the data with a correlation coefficient of 0.9974. The residual error for all standards was less than 15%. The percentage RSDs for the two controls, 2 and 10 ng/ml, were 6.88 and 4.82% (n = 6) and the percentage errors were 7.07 and -6.89% (n = 6), respectively.
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PMID:Heterogeneous post-column immunoreaction detection using magnetized beads and a laboratory-constructed electromagnetic separator. 1271