摘要:

We have analyzed and compared the cyclosporine concentrations in whole blood specimens from heart and kidney transplant patients, using three different methods: high-performance liquid chromatography (HPLC), polyclonal radioimmunoassay, and monoclonal radioimmunossay. HPLC results for heart transplant patients correlated well with the monoclonal (specific antibody) results but did not correlate with the polyclonal (nonspecific antibody) results. All three methods correlated well for renal transplant patients; however, polyclonal results were consistently higher than either monoclonal or HPLC results. We conclude that the results from the monoclonal (specific antibody) RIA are equivalent to HPLC results for both kidney and heart transplant patients.

ISSN:0163-4356    

出版商:OVID    

年代:1989

数据来源: OVID

ISSN:0163-4356    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

This article reports a modified liquid chromatographic fluorescence assay that has proved in our laboratory to give robust performance for the purposes of therapeutic drug monitoring. The sample preparation involves extraction of alkalinized plasma into 1-pentanol/chloroform and back extraction into HCl. Acceptable reproducibility and accuracy data are presented over the concentration range normally encountered in patient samples. The detection limit (25 ng/ml) is approximately one-tenth the lowest calibration standard used in our laboratory for quantitating patient pre-dose specimens, making the method applicable to pharmacokinetic studies.

ISSN:0163-4356    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

An isocratic reversed-phase ion-pair liquid chromatography with UV detection at 350 nm for the determination in human plasma of floctafenin (F) and its three main metabolites—floctafenic acid (FA), hydroxyfloctafenin (HOF), and hydroxyfloctafenic acid (HOFA)—is reported. Analytes and internal standard were extracted from acid plasma into ethyl acetate, and this organic phase was evaporated to dryness. This extraction yielded plasma drug recoveries of >72%. Using 1 ml of plasma, the lower quantification limit was 0.05 mUg ml-1with excellent linearity up to 0.8 mUg ml-1for HOF and HOFA and up to 4.0 mUg ml-1for F and FA. The reproducibility and the selectivity of the method for several drugs thought likely to be administered in conjunction with F, were demonstrated. This method has been successfully applied to a pharmacokinetic study with a single 10 mg kg-1oral dose in ten children.

ISSN:0163-4356    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

A recently developed system for measuring antiepileptic drug concentrations was evaluated for phenytoin and phenobarbital. The apoenzyme reactive immunoassay system was compared with gas-liquid chromatography, EMIT, and TDX systems. Comparisons were performed with control specimens and with sera obtained from patients at three facilities. Precision for all methods was similar, with within-run and between-run coefficients of variation generally 5%. The accuracy of all methods was acceptable, but bias was present in some. However, measurements obtained by a nontechnical person (physician) in a clinical setting were sometimes inaccurate.

ISSN:0163-4356    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

A procedure for determining trimethoprim in serum is reported. It employs the same high-performance liquid chromatographic system described previously for measurement of anticonvulsants, barbiturates, theophylline, caffeine, acetaminophen, and chloramphenicol in serum. The sample preparation for trimethoprim is nearly identical. As a method extension, quantitation of serum trimethoprim on clinical specimens can be easily accommodated as required.

ISSN:0163-4356    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

This report describes the effect of flavin adenine dinucleotide (FAD) and its precursor vitamin B2on an apoenzyme reactivation immunoassay system (ARIS) both in vitro and in vivo. It was observed that 10 nM/L FAD in the buffer causes a false-positive result in ARIS for theophylline by the value of 94 mUM/L, whereas vitamin B2, flavin mononucleotide, adenosine, adenosine monophosphate, and adenosine diphosphate (ADP) at the same concentration caused no such effect. Nevertheless, ADP at 2 mUM/L can cause a drop in theophylline reading of 55 mUM/L. However, the sera from four volunteers with normal liver functions who had taken 30 mg of vitamin B2daily for a week showed no effect on theophylline reading.

ISSN:0163-4356    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We report an assay method for the determination of salivary caffeine concentrations by high-performance liquid chromatography. A simple, new method for collecting mixed saliva using a piece of filter paper has been developed. An arbitrary amount of saliva is absorbed and a fixed amount of internal standard is added. The mean coefficient of variation of measurements repeated by changing both volumes absorbed and caffeine concentrations of saliva was 5.6% with this method. The detection limit was determined to be 0.5 mUg/ml. Precision of measurements and recoveries did not depend upon the volume of saliva absorbed. Four volunteers were given a capsule of 230 mg caffeine, and saliva was collected by the ordinary method using chemical stimulation with citric acid and by our filter paper absorption methods; the methods were compared. Salivary caffeine concentrations were always lower than plasma concentrations, and there were no big differences between two methods, although salivary concentrations measured by our method was higher, with a significant difference at 1.5 h after dosing. From the practical viewpoint this method would be convenient and sufficiently accurate.

ISSN:0163-4356    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We evaluated the Kodak Ektachem clinical chemistry slide for assay of theophylline. Assay precision and accuracy were acceptable in the therapeutic range although precision was poor at low levels of theophylline. The assay performed well with patients' samples using the Abbott TDx as the reference procedure but, as indicated by the manufacturer, uremic samples gave a positive bias, particularly in the therapeutic range. Finally, the significant bias observed with Quality Control material, probably due to matrix sensitivity, is a possible drawback.

ISSN:0163-4356    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Gentamicin concentrations, pharmacokinetic parameters, and calculated doses from enzyme multiplied immunoassay (EMI) and fluorescence polarization immunoassay (FPIA) were compared in 79 samples from 39 patients. Associations between patient factors and the differences between assay results were also assessed. Concentrations were lower when measured by EMI than by FPIA in 71 of the 79 samples (p < 0.001). Mean EMI values for elimination rate constant, volume of distribution, clearance, dose, and daily dose were 10–20% higher than mean FPIA values (p = 0.01). Dosing intervals calculated from EMI and FPIA data were different in 20 pairs of intervals and varied depending on the length of calculated interval. Univariate and multivariate analyses revealed that renal function and the presence or absence of cardiovascular disease, cimetidine, or ranitidine, and heparin were related to differences between the assay results. EMI and FPIA yielded different results for gentamicin concentrations, pharmacokinetic parameters, and calculated daily doses in the clinical setting. Such differences could result in toxic or subtherapeutic doses being administered and may be related, in part, to various patient factors.

ISSN:0163-4356    

出版商:OVID    

年代:1989

数据来源: OVID