Simultaneous determination of propranolol and 4-hydroxypropranolol in plasma by mass fragmentography.

A quantitative method for the simultaneous determination of propranolol and its active metabolite 4-hydroxypropranolol in human plasma is described. Plasma samples are extracted at pH 9.6 with ethyl acetate after the addition of sodium bisulphite and the internal standard oxprenolol. The extracts are derivatized with trifluoroacetic anhydride before separation on a gas chromatograph--mass spectrometer. Detection and quantitation of the trifluoroacetyl derivatives are made by single-ion monitoring. The minimum detectable concentration of propranolol is 1 ng/ml and of 4-hydroxypropranolol 5 ng/ml using 1-ml plasma samples. No interferences from normal plasma constituents or from drugs commonly prescribed together with propranolol were detected.     

Simultaneous determination of propranolol and 4-hydroxypropranolol enantiomers after chiral derivatization using reversed-phase high-performance liquid chromatography

A reversed-phase high-performance liquid chromatographic method is described, which allows the simultaneous quantification of propranolol and 4-hydroxypropranolol enantiomers in human plasma. After extraction from plasma (pH 10.5) using ethyl acetate, the enantiomers are derivatized with R-(+)-phenylethylisocyanate as chiral derivatization reagent and triethylamine as basic catalyst in chloroform. Ascorbic acid is used to prevent 4-hydroxypropranolol from oxidation during the extraction. Chromatographic separation on ODS columns and fluorescence detection (228 nm/greater than 340 nm) allows sensitive quantitation of all derivatives. Incubation of the plasma samples with beta-glucuronidase/arylsulfatase and the use of the specific beta-glucuronidase inhibitor saccharo-1,4-lactone allows the quantitation of both the sulfate and glucuronide conjugates of the enantiomers. The method was applied to human plasma samples from a subject after administration of 60 mg racemic propranolol three times daily.     

Rapid Determination of Propranolol and 4-Hydroxypropranolol in Plasma by High Pressure Liquid Chromatography

Abstract

The resolving power of high pressure liquid chromatography has been combined with the sensitivity of fluorescence detection to develop a method for the determination of propranolol and 4-hydroxypropranolol in plasma. A single selective extraction step precedes chromatography on a high efficiency bonded phase column. The limits of quantitation are approximately 2 ng/ml of plasma for each drug. The analysis of a number of clinical samples has demonstrated the application of the method in pharmacokinetic studies, but the possible interference of other drugs and their metabolites is still under investigation.     

Pharmacokinetics of clenbuterol in the ostrich.

The aim of this study was to investigate the pharmacokinetics of clenbuterol in the ostrich as no such data is available. Clenbuterol (2 mg) was given as a single oral dose to nine ostriches. Blood samples were collected over a period of 96 h after administration and urine for a period of 5 d. Plasma and urine samples were frozen at -20 degrees C pending analysis. Clenbuterol was quantified using a gas chromatograph-mass selective detector. The method for quantification of clenbuterol in plasma was validated by analysing spiked quality control samples at different concentrations. The limit of quantification was determined to be 0.75 ng ml-1 with an absolute recovery of more than 80%. The geometric mean maximum plasma clenbuterol concentration was 4.40 ng ml-1 with 3.0 h as the median time for maximum concentration. The plasma elimination half-life was 19.7 h. The clenbuterol concentration was above 0.75 ng ml-1 in plasma for 48 h and above 1.0 ng ml-1 in urine for 5 d. These data can be useful in residue analysis for clenbuterol in ostriches.     

Determination of selenium in blood plasma and serum by flow injection hydride generation atomic absorption spectrometry

A flow injection hydride generation atomic absorption spectrometric (AAS) method has been used to determine the selenium concentrations of human serum and plasma samples following digestion with nitric, sulphuric and perchloric acids. In the hydride generation process, reduction was carried out by sodium tetrahydroborate to produce a hydride that was atomized in a flame-heated atomisation cell. The method had a detection limit of 1.2 ng ml-1 and a sensitivity of 2.1 ng ml-1. Within-run precisions of 5.8% at 20 ng ml-1 and 4.5% at 80 ng ml-1, and between-run precisions of 4.8% at 69 ng ml-1 and 3.4% at 80 ng ml-1 were obtained. An inter-laboratory comparison study with a graphite furnace AAS method was carried out and the results showed excellent agreement. The flow injection method of sample introduction allowed the use of a sample volume of 330 microliters with an injection rate of 90 injections per hour.     

Comparison of HPLC, capillary electrophoretic and direct spectrofluorimetric methods for the determination of temoporfin-poly(ethylene glycol) conjugates in plasma.

High-performance liquid chromatographic (HPLC), capillary electrophoretic (CE) and direct spectrofluorimetric methods for the determination of temoporfin-poly(ethylene glycol) 2000 conjugate (m-THPC-PEG 2000) in plasma are described and compared. m-THPC-PEG 2000 in plasma was quantitatively extracted (recovery 101-107%) with CH3OH-DMSO (4 + 1 v/v). The supernatant after centrifugation was used for HPLC, CE or direct spectrofluorimetric determination. The major drawback of the HPLC method was that it gave a broad and split peak even under gradient elution conditions, resulting in difficulty in detection and quantification. This is because m-THPC-PEG 2000 consists of a group of compounds with an average molecular mass of approximately 8680 Da owing to the wide molecular mass distribution of PEG 2000 used in the synthesis of the drug. m-THPC-PEG 2000 gave a single and relatively sharp peak when separated by CE with sodium tetraborate buffer (pH 9.45) in the presence of sodium dodecyl sulfate as the running buffer. However, this method lacks the necessary sensitivity for detecting the drug in plasma extract because of the limited sample volume that can be injected. Direct spectrofluorimetry is the method of choice because of its simplicity, specificity and sensitivity. Using an excitation wavelength of 423 nm and the specific emission maximum of 657 nm, the fluorescence intensity could be sensitively measured. The calibration curve constructed by plotting fluorescence intensity against concentration was linear within the range 1.32-1056 ng ml-1. The detection limit (S/N = 3) was 1.32 ng ml-1 and the limit of quantification (S/N = 10) was 2.24 ng ml-1. The precision and reproducibility were assessed by repeated analysis (n = 24) of spiked plasma samples at 350.8 and 699.3 ng ml-1. The RSD was 4.5% and 1.6%, respectively.     

Determination of propranolol and 4-hydroxypropranolol in tissue homogenates by direct injection and column switching HPLC

An improved HPLC method is proposed for simultaneous determination of propranolol (PL) and 4-hydroxypropranolol (4-OH PL) in tissue homogenates.     

Rapid screening for monensin residues in poultry plasma by a dry reagent dissociation enhanced lanthanide fluoroimmunoassay.

Monensin, a carboxylic acid ionophore, is commonly fed to poultry to control coccidiosis. A method for rapid analysis of unextracted poultry plasma samples has been developed based on a novel immunoassay format: one-step all-in-one dry reagent time resolved fluorimetry. All assay specific components were pre-dried onto microtitration plate wells. Only addition of the serum sample diluted in assay buffer was required to perform analysis. Results were available one hour after sample addition. The limit of detection (mean +/- 3s) of the assay calculated from the analysis of 23 known negative samples was 14.2 ng ml-1. Intra- and inter-assay RSD were determined as 15.2 and 7.4%, respectively, using a plasma sample fortified with 50 mg ml-1 monensin. Eight broiler chickens were fed monensin at a dose rate of 120 mg kg-1 feed for one week, blood sampled then slaughtered without drug withdrawal. Plasma monensin concentrations, as determined by the fluoroimmunoassay ranged from 101-297 ng ml-1. This compared with monensin liver concentrations, determined by LC-MS, which ranged from 13-41 ng g-1. The fluoroimmunoassay described is extremely user friendly, gives particularly rapid results and is suitable for the detection and quantification of plasma monensin residues. Data from medicated poultry suggest that analysis of plasma may be useful in predicting the extent of monensin liver residues.     

Production of monoclonal antibody and development of enzyme-linked immunosorbent assay for kanamycin in biological matrices

Monoclonal antibodies (MAbs) against kanamycin were prepared by using a kanamycin-bovine gamma-globulin conjugate for the immunization of mice. Splenocytes from BALB/c immunized mice were fused with P3X63Ag8U.1 myeloma cells. This resulted in two hybridoma cell lines. Fifty per cent inhibition concentrations (IC50) for the MAbs were 2 and 5 ng ml-1. One MAb (IC50 = 2 ng ml-1) was named #22 and was used to develop quantitative assays for kanamycin by means of an enzyme-linked immunosorbent assay (ELISA). The detection limit was 0.2 ng ml-1 and the standard deviations were 0.2-4.4% for intra-assay and 0.6-4.7% for inter-assay, respectively. The detection limits using peroxidase were 4 ppb in cattle milk, cattle plasma, cattle urine, swine plasma, swine urine and chicken plasma. Using the MAb #22 produced, a rapid test kit based on an immunochromatographic method was developed. The detection limits using the kit were 50 ppb in cattle milk, cattle plasma, cattle urine and chicken plasma.     

Quantitative determination of propranolol in plasma and plasma water from normal subjects and patients with angina pectoris by high-performance liquid chromatography

A precise and sensitive high-performance liquid chromatographic method using a column packed with porous polystyrene gel is described for the determination of propranolol in plasma and plasma water from normal subjects and patients with angina pectoris. Propranolol in the samples was extracted with an n-heptane-isoamylalcohol (98.5:1.5) mixture after addition of penbutolol used as an internal standard. The extracts were chromatographed and detected with a spectrofluorophotometer. The quantitative limit of propranolol was 1 ng using 1 ml of plasma or 0.5 ml of plasma water. The present method should be useful for monitoring propranolol concentrations in plasma and plasma water during drug therapy and for pharmacokinetic study of propranolol.     

Determination of 4-nonylphenol and 4-octylphenol in human blood samples by high-performance liquid chromatography with multi-electrode electrochemical coulometric-array detection

Alkylphenols can affect human health because they disrupt the endocrine system. In this study, an analytical method for determining trace amounts of 4-nonylphenol (NP) and 4-octylphenol (OP) in human blood samples was developed. Reversed-phase HPLC with multi-electrode electrochemical coulometric-array detection was used for the determination of NP and OP in plasma and serum samples prepared with a solid-phase extraction method. The separation was achieved using an isocratic mobile phase of 0.7% phosphoric acid-acetonitrile with a C18 reversed phase column. The detection limits of NP and OP were 1.0 and 0.5 ng ml-1, respectively. The recoveries of NP and OP added to human plasma samples were above 70.0% with a relative standard deviation of less than 15.5%. The method was found to be applicable to the determination of NP and OP in various human blood samples such as serum and plasma.     

Sensitive gas chromatographic-mass spectrometric method for the determination of gacyclidine in rat plasma and spinal cord dialyzates

A sensitive gas chromatographic-mass spectrometric (GC-MS) procedure is described for the selective determination of gacyclidine (a non-competitive N-methyl-D-aspartate antagonist) in rat plasma and spinal cord dialyzates. It involves a single-step liquid-liquid extraction of plasma samples and dialyzates with hexane (pH 8.0) and the use of phencyclidine as an internal standard. The compounds were separated on a GC capillary column and specifically detected by MS in the selected-ion monitoring mode. Gacyclidine and its internal standard were monitored by using the fragment ions at m/z 206 and 200, respectively. The method was accurate and reproducible (intra- and inter-day reproducibility < 12%) with a limit of quantification of 1.6 ng ml-1 using 100 microliters plasma of dialyzate samples. The calibration curves for rat plasma and Ringer's solution were linear (r2 > 0.996) over a range from 1.6 to 200 ng ml-1. The extraction efficiency was close to 100%. This simple and rapid assay (total run time < 10 min) was validated for a pilot pharmacokinetic study in healthy rats after intravenous injection of a bolus dose of gacyclidine (2.5 mg kg-1).     

Determination of dextromoramide in plasma and whole blood using high-performance liquid chromatography with ultraviolet absorbance detection.

Dextromoramide was determined in plasma and whole blood after solid-phase isolation by high-performance liquid chromatography using dextropropoxyphene as internal standard and ultraviolet detection at 215 nm. Owing to its good selectivity, sensitivity and reproducibility, the technique is available for forensic toxicology purposes as well as for clinical pharmacology. The concentrations of dextromoramide were determined in three cancer patients receiving intravenous treatment with one to three 5-mg daily doses. On the fourth day the plasma level was 13.85 +/- 3.27 ng ml-1 just before the first daily dose and 84.28 +/- 12.60 ng ml-1 30 min after dosing. The whole blood concentration, determined in one of the patients, was undetectable just before the dose and was 76 ng ml-1 30 min after dosing.     

原子荧光光谱法测定以磷块岩为原料制备磷酸中的砷

本文利用以水作载流的氢化物发生-原子荧光光谱仪测定了以磷块岩为原料自制的磷酸中的砷（As）。利用硫酸法溶融磷块岩自制出磷酸,优化仪器的工作条件,通过条件实验选择出适用于测定砷所需的盐酸和5% L（+）-抗坏血酸-5% 硫脲的用量。原子荧光光谱法测定结果如下：在0.5 ng·mL-1 ~ 8.0 ng·mL-1浓度范围内线性相关系数R2=0.99996;检出限为0.0018 ng·mL-1,样品的相对标准偏差（RSD）为0.82 %,样品的加标回收率在92.4 % ~ 103.4 %。通过与电感耦合等离子体发射光谱法（ICP-OES）比对,结果一致。     

Determination of vitamins D2, D3, K1 and K3 and some hydroxy metabolites of vitamin D3 in plasma using a continuous clean-up-preconcentration procedure coupled on-line with liquid chromatography-UV detection

A semi-automatic procedure for the continuous clean-up and concentration of several fat-soluble vitamins prior to their separation by HPLC and UV detection is reported. The procedure is based on the use of a minicolumn packed with aminopropylsilica as sorbent located prior to the chromatographic detection system. The overall process was developed and applied to the main liposoluble vitamins (A, D2, D3, E, K1, K3) and several hydroxy metabolites of vitamin D3 [25-(OH)-D3,24,25-(OH)2-D3 and 1,25-(OH)2-D3]. All the analytes were monitored at a compromise wavelength of 270 nm. Calibration graphs were constructed between 0.01 and 100 ng ml-1 for vitamin D2 and D3 and their hydroxy metabolites, between 0.1 and 100 ng ml-1 for vitamin A, K1 and K3 and between 1 and 100 ng ml-1 for vitamin E, with excellent regression coefficients (> or = 0.9901) in all cases. The precision was established at two concentration levels with acceptable RSDs in all instances (between 3.6 and 8.7%). The method was appropriate for the determination of vitamin D2, D3, K1 and K3 and the 24,25-dihydroxy and 25-hydroxy metabolites of vitamin D3 in human plasma. The method was applied to plasma samples spiked with the target analytes and the recoveries ranged between 78 and 109%.     

Sensitive fluorimetric determination of formaldehyde by the co-quenching effect of formaldehyde and sulfite on the fluorescence of tetra-substituted amino aluminium phthalocyanine

A novel and sensitive fluorimetric method was developed for the determination of formaldehyde based on the co-quenching effect of formaldehyde and sulfite on the fluorescence of tetra-substituted amino aluminium phthalocyanine. Formaldehyde in the concentration range 0.040-1.19 micrograms ml-1 can be determined with a limit of detection of 7.5 ng ml-1. The relative standard deviation for nine replicate measurements of 80.0 ng ml-1 formaldehyde is 1.8%. The method was applied to the analysis of real samples with satisfactory results.     

Quantitation of 6-(pyridin-3-yl)quinolin-2(1H)-one, a cardiac stimulant, and its N-oxide metabolite in dog plasma by high-performance liquid chromatography.

A method is described for the determination of UK-57,400 (I), a 6-substituted quinoline cardiotonic, and its pyridyl-N-oxide in dog plasma. The analytes are selectively retained from plasma (1 ml) on a solid-phase extraction column and eluted with 1 ml of methanol. After evaporation to dryness, the residue is reconstituted in 100 microliters of the mobile phase. Chromatography is carried out on a Spherisorb 5 microns phenyl high-performance liquid chromatography column, with ultraviolet detection. Calibration curves are linear for concentrations from 10 to 100 ng ml-1. For I, the coefficients of variation at highest and lowest concentrations are 1 and 14%, respectively, while the corresponding figures for the pyridyl-N-oxide metabolite are 4 and 10%, respectively. Sample recovery from extraction is greater than 90%. The limit of detection is 4 ng ml-1 for both analytes.     

Determination of cadmium in biological samples by inductively coupled plasma atomic emission spectrometry after extraction with 1,5-bis(di-2-pyridylmethylene) thiocarbonohydrazide.

An inductively coupled plasma atomic emission spectrometric method for the determination of trace amounts of cadmium after extraction of the metal into isobutyl methyl ketone containing 1,5-bis(di-2-pyridylmethylene) thiocarbonohydrazide is described. The optimum extraction conditions were evaluated from a critical study of the effects of pH, concentration of extractant, shaking time and ionic strength. The detection limit for cadmium is 0.1 ng ml-1 and the calibration is linear from 0.2 to 140 ng ml-1. The relative standard deviation for ten replicate measurements is 2.9% for 2 ng ml-1 of cadmium. Results from the analysis of some certified biological reference materials are given.     

Sensitive determination of paraquat and diquat at the sub-ng ml-1 level by continuous amperometric flow methods.

Two methodologies are described for the determination of paraquat and diquat. The first is based on the pre-treatment of an electrode with a surfactant solution, which improves the electrochemical determination of the herbicides. Linear calibration graphs were obtained in the ranges 10-80 and 10-100 ng ml-1 for paraquat and diquat, respectively. The limits of detection were 6.32 for paraquat and 4.80 ng ml-1 for diquat. The method was applied to the determination of the herbicides in synthetic water samples. The second methodology is based on the preconcentration of paraquat and diquat in a minicolumn packed with a cation-exchange material. The determination ranges and detection limits depend on the sample volume used (5-50 ml). Thus, 50 ml of sample provides limits of detection of 0.016 and 0.020 ng ml-1 for paraquat and diquat, respectively. The applicability of the method was demonstrated with the determination of the herbicides in both synthetic and real water samples.     

Gas chromatographic quantitation of methoxyphenamine and three of its metabolites in plasma

Sensitive gas chromatographic procedures for the determination of methoxyphenamine and three of its metabolites in plasma have been developed. The metabolites were measured using an electron-capture detector. This simple procedure is based on the precipitation of protein from a 1-ml plasma sample with 10% trichloroacetic acid, followed by aqueous derivatization with pentafluorobenzoyl chloride at pH 9.2 and a single-step cyclohexane extraction. The lower limit of detection for the N-desmethyl, O-desmethyl and aromatic 5-hydroxy metabolites of methoxyphenamine were 1.6, 3.1 and 2.2 ng ml-1, respectively, with coefficients of variation less than 10%. The poor electron-capture response of fluorinated derivatives of methoxyphenamine necessitated the use of nitrogen-phosphorus detection. Extractive derivatization with pentafluorobenzoyl chloride, without the need for protein precipitation, enabled quantitation of methoxyphenamine down to 3.8 ng ml-1 from a 2-ml aliquot of plasma. In a pilot study involving healthy volunteers who received a single oral dose of methoxyphenamine hydrochloride plasma concentration could be followed in all three subjects for at least 24, 32, 12 and 4 h for methoxyphenamine and the O-desmethyl, 5-hydroxy and N-desmethyl metabolites, respectively.