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1.
Abstract

A high-performance liquid chromatographic method for analysis of procainamide (PA), and N-acetyl procainamide (NAPA) is presented. Sample preparation employs a simple base-acid double extraction procedure and analysis is carried out on a reverse phase chromatographic system using a μBondapak C18 column and buffered aqueous acetonitrile as the mobile phase. The extraction procedure gives quantitative recovery of both PA and NAPA, and chromatographic results show that drug levels of as low as 0.3 mg per liter of serum can be conveniently analyzed without significant background interferences. The small volume (0.2 ml) of serum needed to perform an analysis makes this method suitable for pharmacokinetic studies in humans and animals as well as for clinical therapeutic drug monitoring studies.  相似文献   

2.
Abstract

Reversed-phase high performance liquid chromatography was applied to the quantitative determination of a new β lactam antibiotic piperacillin. The procedure was applied to human plasma and cerebrospinal fluid samples. After an extraction of plasmaor cerebrospinal fluid by dimethyl formamide, chromatographic separation was effected on a bonded hydrophobic stationary phase with one mobile ohase: methanol-phosphate buffer. This assay was applied to study human pharmacokinetics on ten patients with purulent meningitis during their therapy. Simultaneous determination of piperacillin in plasma and cerebrospinal fluid one and two hours after piperacillin perfusion showed a good penetration of this antibiotic in human cerebrospinal fluid.  相似文献   

3.
ABSTRACT

A new method for the extraction and quantitative determination of amygdalin has been proposed. Accelerated solvent extraction was applied for the extraction, and reversed-phase high-performance thin-layer chromatography method was developed, validated, and applied for the determination of amygdalin in the extracts of apricot, plum, almond, and peach kernels. The chromatographic system used was RP-18 silica, as stationary phase and acetonitrile/water (50:50, v/v), as mobile phase. Densitometric scanning was performed at 210 nm. The method was validated with respect to specificity, linearity, precision, and accuracy. The results showed that the peak area responses were linear within the concentration range of 2.5–50.0 µg/spot (R2 = 0.9984). The limit of quantification was 4.28 µg/spot, and the detection limit 1.28 µg/spot. The intra-day and inter-day reproducibility, in terms of %RSD, were in the range of 0.81–1.15 and 1.32–1.89, respectively. The accuracy data were in the range from 99.98 to 100.56%. The method is linear, quantitative and reproducible, and could be used as an efficient and economical green chromatographic procedure for the determination of amygdalin in the fruit kernel.  相似文献   

4.
《Analytical letters》2012,45(13):1063-1071
Abstract

A rapid, specific and sensitive reversed-phase liquid chromatographic (LC) assay for the quantitative determination of indomethacin in serum without extraction was developed. Chromatographic separation using flunixin meglumine as the internal standard was achieved on octadecylsilane-coated particles with a mobile phase of 0.15 M acetate buffer pH 3.0 (50% v/v), acetonitrile (30% v/v) and methanol (20% v/v). The recovery of indomethacin from serum samples in the concentration range of 0.1-25 μg/ml was 95.5 ± 5.8% and as little as 100 ng/ml of indomethacin in serum samples can be quantitated by this procedure. A serum level versus time profile of dog with intravenously administered indomethacin demonstrated the applicability of the assay.  相似文献   

5.
《Analytical letters》2012,45(16):1351-1361
Abstract

A gas chromatographic method for the determination of trace amounts of some chloro- and nitrophenols is reported. Direct acetylation of chloro- and nitrophenols is carried out by adding acetic anhydride to large volumes of an alkaline aqueous solution of phenols. The stable acetate esters formed improve chromatographic characteristics and also provide for near quantitative extraction using small volumes of methylene chloride. Relative retention times of nine acetates of phenols on 1% SP-1240 A are reported and seven derivatives have been separated. The increased extraction efficiency, short extraction time and small volume of organic solvent used are some of the attractive features of this method in comparison to currently used methods.  相似文献   

6.
Abstract

A method for extraction and quantification of cefmetazole and nocardicins A and E in serum and urine samples is described in this paper. Sample pretreatment is carried out using solid-phase extraction cartridges, resulting in very high extraction recoveries of these β-lactam antibiotics. The procedure, which prepares biological fluids for reversed-phase high-performance liquid chromatographic analysis is convenient, rapid and reproducible. An water-methanol-acetic acid mobile phase was used with benzotriazole as an internal standard. The detection limit was 0.2 μg/ml at 280 nm.  相似文献   

7.
Abstract

A liquid chromatographic method is described for the determination of zinc pyrithione (ZPT) in shampoos, hair conditioners and hair dressings. The method involves simultaneous transchelation to the cupric complex and extraction into methylene chloride. The cupric complex is then separated by normal phase liquid chromatography and detected by UV absorbance at 254 nm. A slight modification of the chromatographic conditions allows the separation of several common impurities. When compared to alternative techniques, this procedure offers improved specificity, precision and accuracy for ZPT, as well as decreased analysis time for multiple samples.  相似文献   

8.
Abstract

A procedure for the rapid, quantitative isolation of doxefazepam from plasma with Supelclean LC-18 cartridges is described together with a sensitive HPLC assay for the quantitative determination of the drug. The recovery of doxefazepam was greater than 80 % over an investigated range of 0.1–2.0 μg/ml of plasma. The column extraction of doxefazepam coupled with the versatility of HPLC make this procedure well suited for detailed pharmacokinetic studies and as well as routine plasma analysis of doxefazepam.  相似文献   

9.
《Analytical letters》2012,45(7):403-409
Abstract

A method capable of determining therapeutic blood levels of pseudoephedrine in man is described. The procedure involves partial purification by extraction, formation of the heptafluorobutyryl derivative, and electron capture detection of the prepared derivatives. Serum levels of pseudoephedrine in man are presented. Chemical reactivity, stability and gas chromatographic properties of the ephedrine derivatives are discussed.  相似文献   

10.
Abstract

Up to the present it has been established that natural hydrocarbons, such as isoprene and the monoterpenes, play an important role in the physical chemistry of the atmosphere because of their high reactivity.

However, their true contribution to the natural chemical system has not yet been clearly defined as the seasonal variations in their concentrations are not sufficiently accurately known due to their low content in the atmosphere (a few hundredths of a ppb to a few ppb). We have developed an analysis procedure which enables quantitative trapping to be carried out together with excellent chromatographic separation. It consists of enrichment on adsorbents followed by very rapid thermal desorption and instantaneous chromatographic injection without further cryogenic trapping.

Our adsorption-desorption cycle does not reduce the efficiency of the chromatographic separation at all and does not bring about any decomposition of these highly reactive plant oils.  相似文献   

11.
Abstract

A high performance liquid chromatographic (HPLC) procedure for the rapid separation of N-acetylaspartic acid, N-acetyl-aspartyl-glutamic acid and N-acetylaspartyl-glutamyl-aspartic acid is described. The procedure utilizes a pellicular ion-exchange column support, and ionic strength gradient with mobile phase solutions buffered to pH 5.0 and a UV detector operated at 210 nm. Reproducibility and quantitative capabilities are also discussed. The method has been used for a tentative estimation of N-acetylaspartic acid and N-acetylaspartyl peptides in a rat brain synaptosomal extract.  相似文献   

12.
《Analytical letters》2012,45(9):1103-1111
Abstract

A simple and sensitive liquid chromatographic assay procedure using a fluorescence detector for the quantitative determination of verapamil in plasma without extraction was developed. After precipitating the protein with acetonitrile, the resulting supernatant liquid was injected onto the column for analysis. Chromatographic separation was achieved on C18 reversed phase column and the eluting solvent was the isocratic mixture of methanol, acetonitrile and pH 3.0 glycine buffer (1:4:5). With this mobile phase the drug and its internal standard were well separated from the interference of the plasma sample. The average recovery of verapamil from 3 replicate samples of different concentration (100–600 ng/mL) were 95.5 ± 5.68%. The minimum amount of verapamil detectable by this method was 40 ng/mL of sample. The elimination half-life (β-phase) of this drug in rabbits was found to be 3.7 hours.  相似文献   

13.
Abstract

A rapid, selective and simple high performance liquid chromatographic (HPLC) assay for methoxamine HC1 has been developed. The analytical procedure involved the use of internal standardization method (1-norephedrine). It has been applied for the qualitative and quantitative determination of methoxamine HC1 in rabbit plasma and in pharmaceutical formulations using an adsorption column in an isocratic mode, with resulting relative standard deviations of 1.7% and 3.3%, respectively. The applicability of the assay procedure to pharmacokinetic studies was demonstrated. Detection limits were as low as 15ng for a 30 ul injection and the determination time was less than 6 minutes.  相似文献   

14.
Abstract

A procedure for the quantitative analysis of the diastereoisomer in methylphenidate hydrochloride is described. The method is based on a high pressure liquid chromatographic separation of the isomers on a Sil-X column with a mobile phase containing ethanol, cyclohexane, chloroform and ammonium hydroxide. The method is simple, precise and accurate and has a limit of detection of 0.1% of the diastereoisomer in the drug substance.  相似文献   

15.
Abstract

A new technique for the extraction of anthracyclines and their metabolites from plasma or serum is described, which gives suitable extracts for HPLC analysis of these drugs in patients. This technique consists in a very rapid chromatographic step on the bonded silica contained in small open columns (C-18 Sep-Paks, Waters Associates). This extraction gives quantitative recoveries of all the anthracyclines and metabolites that have been tested; 0.2 to 3 ml of plasma can be processed, with concentrations up to 5,000 ng/ml. The advantages of this technique over classical techniques using an organic extraction with a partition between two phases are: speed, simplicity, efficacy, reproducibility and similarity of recoveries for various anthracyclines.  相似文献   

16.
《Analytical letters》2012,45(23-24):2307-2315
Abstract

Trazodone, a triazolopyridine derivative with antidepressant activity, is irreversibly oxidized in two steps in a large range of scan rates. The first peak shows a linear dependence on trazodone concentration. This behaviour is used for analytical purposes in determining trazodone concentrations in commercial preparations. An original alternative gas-liquid chromatographic method is also developed. Comparison of the chromatographic with voltammetric methods shows that a) both are sensitive enough to be applied to single tablet assays; b) the major advantage of the voltammetric method for analytical purposes lies in the rapid determination of the trazodone content in tablets. Preparation of the samples is easy and no extraction procedure is required.  相似文献   

17.
《Analytical letters》2012,45(9):697-707
Abstract

A high-performance liquid chromatographic method for determining reserpine in plasma has been developed. The procedure involves extraction of reserpine from buffered plasma into benzene, oxidation of reserpine to a fluorophor by treatment with vanadium pentoxide in phosphoric acid, and chromatographic separation of the reserpine fluorophor on an octadecylsilane column by ion-pairing with heptanesulfonate ions. Fluorescence monitoring of the column effluent provides high sensitivity of detection and increases the specificity of the procedure. A detection limit of approximately 100 pg of reserpine per ml of plasma was obtained following analysis of 2 ml samples. Analysis of a number of samples demonstrated the applicability of this method in confirming the presence of reserpine in equine plasma specimens collected at various horse shows and in evaluating the pharmacokinetic behavior of reserpine following intramuscular administration to horses.  相似文献   

18.
Abstract

A stability indicating high performance liquid chromatographic (HPLC) method for determining hydromorphone hydrochloride in dosage forms is described. The drug was chromatographed on a C18 reverse phase column, using a mobile phase consisting of sodium lauryl sulfate, acetic acid, acetonitrile and water, and detected at 280 nm. Linearity of detector response to the concentration was confirmed. The procedure showed excellent reproducibility and gave quantitative recoveries of the drug from spiked placebos. Photodegraded samples of the dosage form, were assayed by the HPLC procedure and the current USP spectrophotometric procedure. Comparison of the results showed that the USP procedure is only partially stability indicating.  相似文献   

19.
Abstract

A sensitive method for assay of N-propylajmaline (prajmaline) in human plasma is described. The quaternary ammonium compound exists as a pair of stereoisomers, which are isolated and separated by ion-pair liquid-liquid chromatography on microporous silica particles. An aqueous solution containing perchloric acid and sodium perchlorate is used as stationary phase and a mixture of butanol, dichloroethane and hexane as mobile phase. The procedure involves ion-pair extraction from plasma and evaporation prior to the chromatographic separation. Selective detection is achieved by using a fluorescence detector. The method allows assay of concentrations down to 10 pmol of the two forms of prajmaline in 1 ml of plasma with a relative standard deviation below 5 %.  相似文献   

20.
Abstract

Meclofenamic acid is extracted to dichloromethane together with the internal standard diclofenac sodium. After evaporation of the organic solvent the residue is dissolved in the chromatographic eluent and analyzed by liquid chromatography. The acids are separated on a column packed with Spherisorb ODS with methanol - phosphate buffer as the eluent and detected at 280 nm. A possible metabolite of meclofenamic acid was also detected in the chromatograms. The detection limit for meclofenamic acid in plasma was 0.361 μmol/L (0.107 μg/ml) for 1.5 ml sample size. The conditions of quantitative extraction of meclofenamic acid and diclofenac to dichloromethane are given.  相似文献   

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