Simultaneous Determination of Dopamine, Serotonin and Their Metabolites in the Rat Brain by HPLC Method with Coulometric Detection

2000 ◽  
Vol 65 (10) ◽  
pp. 1677-1682 ◽  
Author(s):  
Marcela Bielavská ◽  
Jiří Kassa

A rapid and sensitive method for simultaneous determination of 3-hydroxytyramine (dopamine), 5-hydroxytryptamine (serotonin) and their metabolites - 3,4-dihydroxyphenylacetic acid, 3-methoxytyramine, 4-hydroxy-3-methoxyphenylacetic acid (homovanillic acid) and 5-hydroxyindole-3-acetic acid in the rat brain was developed. Brain samples with the internal standard and heparin were deproteinized by perchloric acid with ethylenediaminetetraacetic acid disodium salt and sodium sulfite. Following homogenization, centrifugation and filtration, the supernatant was directly injected into a reversed-phase HPLC system with coulometric detector. The response of the detected substances was linear in the range 12-700 ng/g of cerebellum homogenate (24-1 400 pg on column). Total recovery of the method was higher than 95%. The method was used for the determination of catecholamines and their metabolites in the chosen part of rat brain following the inhalation exposure to sarin (organophosphate).

2004 ◽  
Vol 72 (2) ◽  
pp. 143-155 ◽  
Author(s):  
M. Sultan ◽  
H. Abdine ◽  
N. Zoman ◽  
F. Belal

A reversed-phase HPLC method with spectrophotometric detection was developed for the simultaneous determination of labetalol (LBT) and hydrochloro-thiazide (HCD). The chromatographic separation was performed using a Microbondapak C18 column (4.6 i.d. x 250 nm) and paracetamol as internal standard. A mobile phase consisting of 0.05 M phosphate buffer/acetonitrile of pH 4 (7:3) at a flow rate of 0.7 ml/min was used. The detection was affected spectrophotornetrically at 302 nm. The working concentration range was 0.3–10 µg/ml with detection limits of 0.05 µg/ml for both drugs. The lower quantitation limit was 0.25 µg/ml in the two cases. The method was successfully applied to tablets, the % recoveries were 99.45 ± 0.68 for LBT and 99.79 ± 0.75 for HCD. The method was extended to the in-vitro determination in spiked human plasma. The % recoveries were 91.12 ± 0.33 for LBT and 91.37 ± 0.40 for HCD. The interday and intraday precision and accuracy were evaluated in plasma by calculating the % RSD (n=5) and the % error and were found to be in the ranges of 1.18–4.1% and 0.38–0.36% for both drugs, respectively.


Author(s):  
Hina Shamshad ◽  
Ali Sayqal ◽  
Jahan Zeb ◽  
Agha Zeeshan Mirza

Abstract A simple, accurate and precise RP-HPLC method was developed for the simultaneous determination of chloroquine, pyrimethamine and cetirizine hydrochloride concentrations in bulk drug and human serum. The assay was performed using a mobile phase of methanol: water (70:30) at pH of 2.8 ± 0.05 on the Purospher C-18 column with UV detection at 230 nm and rosuvastatin used as an internal standard. The retention times observed for chloroquine, pyrimethamine and cetirizine hydrochloride were 3.5, 2.5 and 5.5 minutes, respectively. The method was found to be specific for the assayed drugs showing a linear response in the concentration range of 1–100 μg mL−1 with coefficients of determination values of (r = 0.999). The method was developed and validated according to ICH guidelines. The method was used to monitor the serum samples and was found to be sensitive for therapeutic purposes, showing the potential to be a useful tool for routine analysis in laboratories.


2011 ◽  
Vol 8 (1) ◽  
pp. 340-346 ◽  
Author(s):  
Rajesh M. Kashid ◽  
Santosh G. Singh ◽  
Shrawan Singh

A reversed phase HPLC method that allows the separation and simultaneous determination of the preservatives methyl paraben (M.P.) and propyl paraben (P.P.) is described. The separations were effected by using an initial mobile phase of water: acetonitrile (50:50) on Inertsil C18 to elute P.P. and M.P. The detector wavelength was set at 205 nm. Under these conditions, separation of the two components was achieved in less than 10 min. Analytical characteristics of the separation such as precision, specificity, linear range and reproducibility were evaluated. The developed method was applied for the determination of preservative M.P. and P.P. at concentration of 0.01 mg/mL and 0.1 mg/mL respectively. The method was successfully used for determining both compounds in sucralfate suspension.


2012 ◽  
Vol 48 (2) ◽  
pp. 315-323 ◽  
Author(s):  
Paulo Cesar Pires Rosa ◽  
Isabel Cristina Sales Fontes Jardim

A new, simple, fast, reproducible and sensitive reversed phase HPLC method, using a new stationary phase containing embedded urea polar groups, has been developed and validated for the simultaneous determination of clobutinol hydrochloride (CLO) and doxylamine succinate (DOX) in syrups. The determination was carried out on a C8 urea column (125 mm x 3.9 mm i.d., 5 µm particle size) synthetized at the Liquid Chomatography Laboratory (LabCrom) of the Chemistry Institute of Unicamp. The mobile phase consisted of a mixture of acetonitrile:methanol:phosphate buffer (pH 2.5) in the gradient mode. The diode array detector (DAD) was operated at 230 nm for CLO and 262 nm for DOX. The method showed adequate precision, with relative standard deviations (RSD) less than 1%. The presence of the excipients did not interfere in the results of the analysis. Accuracy was determined by adding standards of the drugs to a placebo and good recovery values were obtained. The analytical curves were linear (r² 0.9999 for CLO and 0.9998 for DOX) over a wide concentration range (2.4-336 µg mL-1 for CLO and 2.3-63 µg mL-1 for DOX). The solutions were stable for at least 72 hours at room temperature. The criteria for validation using the ICH guidelines were fulfilled.


Author(s):  
Sushil D. Patil ◽  
Pravin B. Shelke ◽  
Priti Aher ◽  
Maswood Ahmed Hafizur Rahman

A simple, rapid, economic, sensitive and precise HPLC method has been developed for the simultaneous determination of Sulphadoxine and Pyrimethamine in pharmaceutical dosage form by taking Tolterodine as an internal standard. The method was carried out using Phenomenex C18 (4.6ID × 250mm; 5µm) column and mobile phase comprised of methanol and Phosphate Buffer in proportion of ratio 60:40 v/v. The flow rate was 1.0mL/min and detection was carried out at 276nm. The retention time of Sulphadoxine, Pyrimethamine and Tolterodine were found to be 2.967, 4.058 and 6.908 respectively. Linearity of Sulphadoxine and Pyrimethamine in the range of 2 to 12μg/mL and 4 to 24μg/mL respectively. The % recoveries of Sulphadoxine and Pyrimethamine were found to be in between 99.93% to 99. 96 % respectively. The proposed method is suitable for the routine quality control analysis for simultaneous determination of Sulphadoxine and Pyrimethamine was in bulk and pharmaceutical dosage form.


1998 ◽  
Vol 44 (7) ◽  
pp. 1481-1488 ◽  
Author(s):  
Maria Shipkova ◽  
Paul Dieter Niedmann ◽  
Victor William Armstrong ◽  
Ekkehard Schütz ◽  
Eberhard Wieland ◽  
...  

Abstract We describe a reversed-phase HPLC method for determination of total mycophenolic acid (MPA), its free concentration (MPAf), and the glucuronide metabolite (MPAG), based on simple sample preparation and gradient elution chromatography. The compounds were quantified in parallel by absorbance at 254 nm and 215 nm in the internal standard mode. Linearity was verified up to 50 mg/L for MPA and up to 500 mg/L for MPAG (r >0.999). Detection limits at 215 and 254 nm were, respectively, 0.01 and 0.03 mg/L for MPA, and 0.03 and 0.1 mg/L for MPAG. The recovery of MPA was 95–106%;recovery of MPAG was 96–106%. The imprecision (CV) for MPA (0.2–25 mg/L) was <8.4% (254 nm) and <4.4% (215 nm) within day (n = 12) and <9.2% (254 nm) and <6.2% (215 nm) between days (n = 12). The imprecision for MPAG (10–250 mg/L) was <4.9% (254 nm) and <3.4% (215 nm) within day, and <6.1% (254 nm) and <5.9% (215 nm) between days. For quantification of MPAf, 100 μL of ultrafiltrate was applied directly to the column. The detection limit was 0.005 mg/L at 215 nm and 0.015 mg/L at 254 nm. In the range between 18–210 μg/L, the within-day CVs were <11.8% (n = 12) and the between-day CVs were <15.8% (n = 12).


2010 ◽  
Vol 93 (4) ◽  
pp. 1077-1085 ◽  
Author(s):  
Nafiz O Can ◽  
Goksel Arli

Abstract Development and validation of an RP-HPLC method for determination of levetiracetam in pharmaceutical tablets is described. The separation and quantification of levetiracetam and caffeine (internal standard) were performed using a single analytical procedure with two different types of stationary phases, conventional Phenomenex Gemini C18 (100 4.6 mm, 5 m) and Merck Chromolith Performance RP18e (100 4.6 mm, macropore size 2 mm, micropore size 13 nm) monolithic silica. Five-microliter aliquots of samples were injected into the system and eluted using wateracetonitrile (90 + 10, v/v) mobile phase pumped at the rate of 1 mL/min. The analyte peaks were detected at 200 nm using a diode array detector with adequate resolution. Validation studies were performed using the method recommended by the International Conference on Harmonization, the U.S. Pharmacopeia, and AOAC INTERNATIONAL, which includes accuracy, precision, range, limits, robustness, and system suitability parameters. Levetiracetam and caffeine were detected in about 7 min using the conventional column, whereas less than 5 min was required when the monolithic column was used. Calibration plots had r values close to unity in the range of 0.88.0 g/mL. Assay of levetiracetam in a tablet formulation was demonstrated as an application to real samples.


2010 ◽  
Vol 93 (5) ◽  
pp. 1503-1514 ◽  
Author(s):  
Sumita Dixit ◽  
Subhash K Khanna ◽  
Mukul Das

Abstract A simple and sensitive HPLC method has been developed for the simultaneous determination of eight permitted food colors and five commonly encountered nonpermitted colors in various food commodities, including sugar-, fat-, and starch-based food matrixes. The method uses a specific food category-based cleanup/treatment procedure before color extraction to avoid the interference of food matrixes, and to obtain the optimal color extraction. Analysis was performed on a reversed-phase C18 -Bondapak column with ammonium acetate and acetonitrile gradient elution as the mobile phase; a programmable max-specific visible detection was used to monitor colors to obtain the higher sensitivity and expanded scope needed for multicolor blends having diverse absorption maxima. All colors showed good linearity, with regression coefficients of 0.99740.9999. The LOD and LOQ values ranged from 0.01 to 0.12 mg/L, and from 0.04 to 0.83 mg/L or mg/kg, respectively. The intraday and interday precision tests produced good RSD values, and the recoveries from different food matrixes ranged from 82 to 104%. The method offers high sensitivity for analysis of a wide variety of food matrixes containing a broad scope of multicolor blends. Two nonpermitted colors, orange II and metanil yellow, were found. Also, a number of samples contained permitted colors at levels two-to seven-fold higher than those prescribed.


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