Fluorometric determination of indocyanine green in plasma.

1987 ◽  
Vol 33 (6) ◽  
pp. 765-768 ◽  
Author(s):  
B Hollins ◽  
B Noe ◽  
J M Henderson

Abstract With this fluorometric method for measuring indocyanine green (ICG) in biological fluids, the limit of detection is an order of magnitude lower than for the traditional spectrophotometric procedure. The excitation and emission maxima are 780 and 810 nm, respectively. Agreement was excellent (r = 0.998) between direct results by this method and those by a liquid-chromatographic procedure with spectrophotometric detection. ICG breaks down in aqueous solution; the degradation products can be detected with liquid-chromatographic/spectrophotometric methods, but because the metabolites are not fluorescent, they do not interfere in the method present here. The increased specificity and sensitivity of this method should permit much more complete analysis of the kinetics of ICG disposition.

1984 ◽  
Vol 67 (5) ◽  
pp. 913-915
Author(s):  
Chih-Kuang Chou ◽  
David C Locke

Abstract A rapid, precise, and accurate liquid chromatographic (LC) method is described for the determination of benzoyl peroxide (BP) in acne preparations. BP is extracted from a water dispersion of the preparation with dichloromethane (DCM), and an aliquot is eluted from a C-18 reverse phase LC column with acetonitrile-O.lOM aqueous NaCI04. Selective and sensitive quantitation is accomplished with a reductive mode electrochemical detector. This detector is an order of magnitude more sensitive than a 240 nm UV absorption detector; the lower limit of detection is 2 ng for a 4 μL injection. The recovery of BP is 99.4% and the detector response is linear to at least 2 μg per 4 μL injection.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Mei-Liang Chin-Chen ◽  
Maria Rambla-Alegre ◽  
Abhilasha Durgbanshi ◽  
Devasish Bose ◽  
Sandeep K. Mourya ◽  
...  

A liquid chromatographic procedure has been developed for the determination of carbaryl, a phenyl-N-methylcarbamate, and its main metabolite 1-naphthol, using a C18 column (250’mm’ × ’4.6’mm) with a micellar mobile phase and fluorescence detection at maximum excitation/emission wavelengths of 225/333’nm, respectively. In the optimization step, surfactants sodium dodecyl sulphate (SDS), Brij-35 andN-cetylpyridinium chloride monohydrate, and organic solvents propanol, butanol, and pentanol were considered. The selected mobile phase was 0.15’M SDS-6% (v/v)-pentanol-0.01’M NaH2PO4buffered at pH 3. Validation studies, according to the ICH Tripartite Guideline, included linearity (r>0.999), limit of detection (5 and 18’ng mL-1, for carbaryl and 1-naphthol, resp.), and limit of quantification (15 and 50’ng mL-1, for carbaryl and 1-naphthol, resp.), with intra- and interday precisions below 1%, and robustness parameters below 3%. The results show that the procedure was adequate for the routine analysis of these two compounds in water, soil, and vegetables samples.


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Zarna R. Dedania ◽  
Ronak R. Dedania ◽  
Navin R. Sheth ◽  
Jigar B. Patel ◽  
Bhavna Patel

The objective of the current study was to develop a validated stability-indicating assay method (SIAM) for risperidone after subjecting it to forced decomposition under hydrolysis, oxidation, photolysis, and thermal stress conditions. The liquid chromatographic separation was achieved isocratically on a symmetry C18 column (5 μm size, 250 mm × 4.6 mm i.d.) using a mobile phase containing methanol: acetonitrile (80 : 20, v/v) at a flow rate of 1 mL/min and UV detection at 280 nm. Retention time of risperidone was found to be . The method was linear over the concentration range of 10–60 μg/mL with a limit of detection and quantitation of 1.79 and 5.44 μg/mL, respectively. The method has the requisite accuracy, specificity, sensitivity, and precision to assay risperidone in bulk form and pharmaceutical dosage forms. Degradation products resulting from the stress studies did not interfere with the detection of Risperidone, and the assay is thus stability indicating.


2019 ◽  
Vol 10 (4) ◽  
pp. 3717-3727
Author(s):  
Dawood CH. Al-Bahadily ◽  
Rasool Chaloob ◽  
Kulood H. Oudah ◽  
H. N. K. AL-Salman ◽  
Falah Hassan Shari ◽  
...  

In this study, a simple and reliable stability-indicating RP-HPLC method was developed and validated for the analysis of Nystatin in the pharmaceuticals. The chromatographic separation was performed in the isocratic mode on an Ion Pac column; Arcus EP‑C18; 5μm, 4.6×250 mm, 30 °C) using a mobile phase consisting of ammonium acetate 0.05 M buffer/ Methanol mixture (30:70) and a flow-rate of 1.0 mL/min with UV detection at 305 nm. The flow rate was set at 1.0 mL/min. The HPLC analysis method was validated in terms of linearity, precision, accuracy, specificity, and sensitivity, according to International Conference on Harmonization (ICH) guidelines. The results indicated that the retention time was 8 min, and no interferences were observed from the formulation excipients and stress degradation products.  The specificity, linearity, precision, accuracy, LOD, and LOQ of the method were validated. The method was linear over the range of 5–500 μg/mL with an acceptable correlation coefficient (R2 = 0.9996). The method’s limit of detection (LOD) and quantification (LOQ) were 0.01 and 0.025 μg/mL, respectively. The results indicate that this validated method can be used as an alternative method for the assay of nystatin. This validated HPLC method could be used for routine analysis, quality control, and the stability of analysis of Nystatin formulations.


2008 ◽  
Vol 91 (4) ◽  
pp. 709-719 ◽  
Author(s):  
Gulshan Bansal ◽  
Manjeet Singh ◽  
Kaur Chand Jindal ◽  
Saranjit Singh

Abstract A forced degradation study on glibenclamide was performed under conditions of hydrolysis, oxidation, dry heat, and photolysis and a high-performance column liquid chromatographic-ultraviolet (HPLC-UV) method was developed to study degradation behavior of the drug under the forced conditions. The degradation products formed under different forced conditions were characterized through isolation and subsequent infrared/nuclear magnetic resonance/mass spectral analyses, or through HPLC/mass spectrometric (HPLC/MS) studies. The drug degraded in 0.1 M HCl and water at 85C toamajor degradation product, 5-chloro-2-methoxy-N-2-(4-sulfamoylphenyl)ethyl]benzamide (III), and to a minor product, 1-cyclohexyl-3-[[4-(2-aminoethyl)-phenyl]sulfonyl]urea (IV). Upon prolonged heating in the acid, the minor product IV disappeared, resulting in formation of 5-chloro-2-methoxy-benzoic acid (II) and an unidentified product (I). Heating of the drug in 0.1 M NaOH at 85C yielded II and IV as the major products and I and III as the minor products. The drug and the degradation products formed under different conditions were optimally resolved on a C18 column using ammonium acetate buffer (0.025 M, pH 3.5)acetonitrile (45 + 55) mobile phase at a flow rate of 0.6 mL/min, with detection at 230 nm. The method was validated for linearity, precision, accuracy, and specificity. Limit of detection (LOD) and limit of quantitation (LOQ) values were also determined. The method could be successfully applied for simultaneous quantification of glibenclamide and the major product, III. The response of the method was linear in a narrow [0.410 g/mL, correlation coefficient (r2 = 0.9982] and a wide (0.4500 g/mL, r2 = 0.9993) concentration range for glibenclamide, and in the concentration range of 0.02550 g/mL (r2 = 0.9998) for III. The method proved to be precise and accurate for both glibenclamide and III. It was specific for the drug and also selective for each degradation product, and LOQ values for the drug were 0.1 and 0.4 g/mL, whereas those for III were 0.010 and 0.025 g/mL, respectively.


2008 ◽  
Vol 91 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Jlia Menegola ◽  
Martin Steppe ◽  
Elfrides E S Schapoval

Abstract Column high-performance liquid chromatographic (LC) and UV spectrophotometric methods for the quantitative determination of citalopram, a potent and selective serotonin reuptake inhibitor, in tablets were developed. The parameters linearity, precision, accuracy, specificity, robustness, limit of detection, and limit of quantitation were studied according to International Conference on Harmonization guidelines. Chromatography was carried out by the reversed-phase technique on an ACE C18 column with a mobile phase composed of 0.30 triethylamine solutionacetonitrile (55 + 45, v/v) adjusted to pH 6.6 with 10 ortho-phosphoric acid at a flow rate of 1.0 mL/min and 25C. The UV spectrophotometric method was performed at 239 nm. The linearity of the LC method was in the range of 10.0070.00 g/mL, and 2.5017.50 g/mL for the UV spectrophotometric method. The interday and intraday assay precision was <1.5 (relative standard deviation) for the LC and UV spectrophotometric methods. The recoveries were in the range 100.70101.35 for the LC method and 98.4898.65 for the UV spectrophotometric method. Statistical analysis by Student's t-test showed no significant difference between the results obtained by the 2 methods. The proposed methods are highly sensitive, precise, and accurate and can be used for the reliable quantitation of citalopram in tablets.


1992 ◽  
Vol 75 (1) ◽  
pp. 62-65 ◽  
Author(s):  
R Khazanchi ◽  
S Walia ◽  
S K Handa

Abstract A reversed-phase liquid chromatographic method has been developed for the determination of fenamiphos and the metabolites fenamiphos sulfoxide, fenamiphos sulfone, 3-methyl-4-(methylthlo)- phenol, and 3-methyl-4-(methylsulflnyl)phenol. Trace quantities of the nematlclde and Its metabolites In soil can be determined simultaneously. The limit of detection of the method was 5 ppm. Recoveries of fenamiphos and Its degradation products at fortification levels of 25,50, and 100 ppm ranged from 99.2 to 100.8%. Standard deviations ranged from 0.29 to 0.70 ppm.


1984 ◽  
Vol 30 (2) ◽  
pp. 319-322 ◽  
Author(s):  
W Mastropaolo ◽  
D R Holmes ◽  
M J Osborn ◽  
J Rooke ◽  
T P Moyer

Abstract In this improved reversed-phase liquid-chromatographic procedure for determination of mexiletine in plasma, mexiletine and an internal standard, chlorodisopyramide, are extracted with methylene chloride from 0.5 mL of serum or plasma; the extract is then concentrated and injected onto a C18 chromatographic column. Mexiletine in the column effluent is detected by monitoring absorbance at 210 nm. It is quantified by use of mexiletine-internal standard peak-height ratios. The relation between this ratio and mexiletine concentration is linear from 0.1 to 5.0 mg/L. The lower limit of detection is about 50 micrograms/L. At a mexiletine concentration of 2.0 mg/L in serum, intrarun precision (CV) is 2.9% and inter-run precision is 5.9%; at 0.5 mg/L, these CVs are 5.7% and 9.6%, respectively. Analytical recovery of added mexiletine in serum is 68-88%. Therapeutic concentrations of some commonly administered drugs in patients' specimens did not interfere. In serum from 38 patients receiving mexiletine for cardiac arrhythmia, concentrations measured by this method correlated with therapeutic efficacy.


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