The authors describe a rapid, useful, specific, and very sensitive high-performance liquid chromatographic assay for the determination of fluvastatin (FV) level using atorvastatin as the internal standard (IS). After a simple deproteinization of 1.0 mL of plasma with acetonitrile, the drug and IS were extracted with tert-methyl butyl ether (TMBE).
View Article and Find Full Text PDFThe authors describe a useful and rapid micromethod for the analysis of itraconazole (ITZ) and its active metabolite hydroxyitraconazole (HIT) in human plasma. After a simple deproteinization of 100 microL plasma with acetonitrile, the drug, its metabolite, and an internal standard (IS, ketoconazole) were separated on an 8 mm x 10 cm NovaPak (Waters Associates; Milford, MA) C(18) 4-microm particle-size radial compression cartridge. The compounds of interest were detected using a fluorescence detector with the excitation wavelength set at 260 nm and the emission at 365 nm.
View Article and Find Full Text PDFCaffeine has been used frequently in the treatment and prevention of apnea of prematurity. The metabolism of caffeine depends on the activities of the hepatic enzymes that vary from one infant to another. The objective of this study was to determine the influence of postnatal age (PNA), birth weight (BW), study weight (SW), gestational age (GA), postconceptual age (PCA), and gender on the maturation of caffeine metabolism in premature infants.
View Article and Find Full Text PDFJ Chromatogr B Biomed Sci Appl
April 2001
This study describes an expedient assay for the analysis of the asthma medication, montelukast sodium (Singulair, MK-0476), in human plasma samples. After a simple extraction of the plasma, the drug and internal standard, quinine bisulfate, were measured by HPLC. The chromatographic system consisted of a single pump, a refrigerated autosampler, a C8 4-microm particle size radial compression cartridge at 40 degrees C and a fluorescence detector with the excitation and emission wavelengths set at 350 and 400 nm, respectively.
View Article and Find Full Text PDFJ Pharm Biomed Anal
March 2000
A rapid, specific and very sensitive liquid chromatographic assay using standard ultraviolet detection has been developed to measure cefazolin (CFZ) or ceftriaxone (CFX) in small samples (200 microl) of plasma using either drug as the internal standard for measurement of the other. A rapid extraction was performed using C18 bonded Sep Pak cartridges with high extraction efficiency for both drugs. The chromatographic system employed the use of a Nova-Pak C18 4-microm cartridge with a radial compression system preceded by a Guard-Pak with a C18 insert.
View Article and Find Full Text PDFThis study was undertaken to investigate the pharmacokinetics of etoposide for optimizing its oral dosage in elderly patients with non-Hodgkin's lymphoma (NHL) using the fraction of dose absorbed calculated from the data generated from first oral and intravenous doses in the same patient. Twenty-three NHL patients (ages 61-95 years) entered this study. Each received 50 mg/m2 of etoposide by 1-hour i.
View Article and Find Full Text PDFThe authors describe a simplified high-performance liquid chromatographic (HPLC) method for the determination of gentamicin sulfate (GEN) in microsamples of plasma using 9-fluorenylmethyl chloroformate (FMOC) as a derivatizing agent and neomycin sulfate as the internal standard (IS). The drug and IS were separated on a 4 microm (particle size), 8 x 100 mm Nova-Pak C18 radial compression cartridge using a mixture of 84.5% acetonitrile and 15.
View Article and Find Full Text PDFBiol Trace Elem Res
July 1999
We measured selenium (Se) levels in the urine and blood plasma samples of 72 Saudi Arabian patients with dilated cardiomyopathy (DCM) and 70 control subjects of the same origin. To correct for differences in the hydration state of the subjects, the selenium concentration for each urine sample was normalized by dividing it by the concentration of creatinine (CREAT) in the same sample. The median (and range) of the values found for the concentration of Se in plasma, urine, and normalized concentration in urine for the control subjects was 1.
View Article and Find Full Text PDFMeasurement of salivary clearance and urinary metabolites of caffeine is an excellent noninvasive tool for assessing liver function, particularly the activity of cytochrome P4501A2 (CYP1A2), N-acetyltransferase (NAT), and xanthine oxidase (XO). This study was undertaken to measure the clearance of caffeine using saliva as a biological fluid and to assess the activities of the above-mentioned enzymes in healthy children and pediatric patients with liver diseases using urinary molar ratios of different caffeine metabolites. The well-established two-sample saliva approach was used to measure the clearance of caffeine in nine pediatric patients with liver diseases (LD) and in nine healthy children.
View Article and Find Full Text PDFThe urinary excretion and pharmacokinetics of acrolein (ACRO) and its parent drug cyclophosphamide (CP) were investigated in 16 randomly selected bone marrow transplant (BMT) recipients when CP was used for conditioning. Patients suffering from aplastic anemia (n = 3) received a 4-day course of CP at a dose of 50 mg/kg daily infused intravenously (i.v.
View Article and Find Full Text PDFThis study was undertaken to examine the pharmacokinetics of mesna and its dimer form, dimesna, in the plasma and urine of patients undergoing bone marrow transplantation who received 130 mg/kg of mesna divided intravenously into a 30-mg/kg bolus dose followed immediately by 100 mg/kg infused over 12 hours for uroprotection. The relationship between and urinary excretion of mesna and dimesna also was examined by comparing the data obtained in patients who developed hemorrhagic cystitis versus those who did not. Blood and urine samples were collected at different time intervals after administration, and the plasma or urine was analyzed by liquid chromatography with electrochemical detection.
View Article and Find Full Text PDFWe describe in this report an expedient and accurate liquid chromatographic method for measurement of mesna and dimesna in plasma and urine. The separation of mesna and the internal standard (p-aminobenzoic acid, IS) was achieved on a 10-microns, 8 mm (i.d.
View Article and Find Full Text PDFWe describe an assay for acrolein in urine, employing derivatization with m-aminophenol in the presence of ferrous sulfate solution in sulfuric acid. The derivative (7-OH quinoline; DER) and the internal standard (quinine-bisulfate; IS) were separated on a 10-micron particle, 8 mm x 10-cm C18 cartridge in conjunction with a radial compression system using a mixture of 0.05 M dibasic ammonium phosphate solution (pH 2.
View Article and Find Full Text PDFA method for the analysis of hydroxyurea (HU) in solutions, powder, or capsules by use of capillary gas chromatography with N-P thermionic specific detection is described. Upon injection of an HU solution in a methanol and acetone mixture, the drug formed pyridine which was well separated from the internal standard (thiotepa) on a 30-m fused-silica, SE-30 capillary column with temperature programming. The peak height ratio versus concentration standard curves were linear with correlation coefficient ranging between 0.
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