Fluorometric Determination of Plasma 11-Hydroxycorticosteroids. I. Rapid Procedure for Clinical Screening

Abstract A method proposed by Kitabchi and Kitchell [Anal. Biochem. 34, 529 (1970)] for the fluorometric determination of plasma 11-hydroxycorticosteroids has been modified. It is simplified by eliminating centrifugations, by processing all samples consecutively (rather than in small groups), by using disposable test tubes, and by prealkalinizing standards and blanks as well as plasma samples. Specificity and sensitivity are increased by measuring fluorescence at 520 nm, with an excitation wavelength of 470 nm. Effects of prealkalinization and time of fluorescence development on final cortisol values were studied. Large fluorescence increases are possible after 60 min of fluorescence development. Cortisol recoveries were not changed by the use of phase-separating filter paper nor were cortisol values altered by partial aging of the fluorescence reagent. Sensitivity, specificity, accuracy, and precision of the proposed method are reported.

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Rapid Fluorometric Determination of Benzo(a)pyrene in Foods

Journal of Food Protection ◽

10.4315/0362-028x-45.2.139 ◽

1982 ◽

Vol 45 (2) ◽

pp. 139-142 ◽

Cited By ~ 3

Author(s):

YASUHIDE TONOGAI ◽

SHUNJIRO OGAWA ◽

MASATAKE TOYODA ◽

YOSHIO ITO ◽

MASAHIRO IWAIDA

Keyword(s):

Detection Limit ◽

Peak Height ◽

Excitation Wavelength ◽

Activated Alumina ◽

Fluorometric Method ◽

Fluorometric Determination ◽

Standard Curve ◽

Layer Chromatography ◽

Entire Procedure

A simple and rapid fluorometric method for determining benzo (a) pyrene in foods was developed. Benzo (a) pyrene is extracted from foods with n-hexane:ether mixture (4:1), purified through a column of activated alumina and determined fluorometrically. An excitation wavelength of 295 nm and emission wavelength of 403 nm were used for calculating concentrations of benzo (a) pyrene. The peak height at 403 nm and baseline between 392 and 418 nm were employed to derive a standard curve for quantitating benzo (a) pyrene. A calibration curve for between 0.04 – 4 ng/ml of benzo (a) pyrene was used. Recoveries of benzo (a) pyrene from 14 kinds of food spiked at levels of 20 and 2ppb were within the range of 79.5 – 93.8% and 50.0 – 80.6%, respectively. The entire procedure takes only one hour with the detection limit being 0.1 ppb. Benzo (a) pyrene detected was reconfirmed by thin-layer chromatography.

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Stability-Indicating Spectrofluorometric Method for the Determination of Some Cephalosporin Drugs via Their Degradation Products

Journal of AOAC International ◽

10.5740/jaoacint.14-088 ◽

2015 ◽

Vol 98 (2) ◽

pp. 361-370 ◽

Cited By ~ 2

Author(s):

Nadia M Mostafa ◽

Laila Abdel-Fattah ◽

Soheir A Weshahy ◽

Nagiba Y Hassan ◽

Shereen A Boltia

Keyword(s):

Degradation Products ◽

Hplc Method ◽

Excitation Wavelength ◽

Pharmaceutical Dosage Forms ◽

Stability Indicating ◽

Acid Degradation ◽

Accuracy And Precision ◽

Spectrofluorometric Method ◽

Good Agreement

Abstract A stability-indicating spectrofluorometric method was investigated for the determination of three cephalosporin drugs, namely, cefpodoxime proxetil (CPD), cefixime trihydrate (CFX), and cefepime hydrochloride (CPM), via their acid and alkali degradation products. The three drugs were determined via their acid degradation at 432, 422, and 435 nm using an excitation wavelength of 310, 330, and 307 nm for CPD, CFX, and CPM determination, respectively, and via their alkali degradation at 407, 411, and 405 nm using an excitation wavelength of 310, 305, and 297 nm for CPD, CFX, and CPM determination, respectively. Linearity was achieved in the ranges of 0.35–3.50,0.4–4.0, and 0.3–3.0 μg/mL for the acid degradation products of CPD, CFX, and CPM, respectively, and in ranges of 0.05–0.5, 0.1–1.0, and 0.08–0.80 μg/mL for the alkali degradation products of CPD, CFX, and CPM, respectively. The method was validated for various parameters according to International Conference on Harmonization guidelines. The method was successfullyapplied for the determination of these cephalosporindrugs in pharmaceutical dosage forms with good accuracy and precision. The results obtained by the proposed spectrofluorometric method were compared with good agreement to the official HPLC method.

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Bioanalytical Method Validation for the Determination of Warfarin in Spiked-Saliva Using Fluorometric HPLC for TDM Application

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1162.173 ◽

2021 ◽

Vol 1162 ◽

pp. 173-179

Author(s):

Ari Wibowo ◽

Shabrina Nurbaiti ◽

Vitarani Dwi Ananda Ningrum

Keyword(s):

Method Validation ◽

Mobile Phase ◽

Geriatric Patients ◽

Therapeutic Drug ◽

Excitation Wavelength ◽

Bioanalytical Method Validation ◽

Bioanalytical Method ◽

Non Invasive ◽

Accuracy And Precision

Saliva becomes an alternative biological matrix for therapeutic drug monitoring (TDM) application since there is a strong correlation between warfarin plasma concentration and saliva; further, the sampling is non-invasive and more comply with pediatric and geriatric patients. This study aims to validate the parameters of the warfarin bioanalytical method in spiked-saliva according to the criteria from the Food and Drug Administration (FDA) in the Guidance for Industry Bioanalytical Method Validation. The method used is Fluorometric HPLC with an excitation wavelength of 310 nm and an emission wavelength of 390 nm. The mobile phase involved is phosphate buffer-methanol, and the stationary phase is C18. The LoD and LoQ obtained are 0.71 ng/mL and 2.16 ng/mL, respectively. The coefficient of variation and %diff in the selectivity, accuracy, and precision parameters have met the criteria of the bioanalytical method of less than 20%. Meanwhile, the average %recovery is 101.30%. To conclude, the developed warfarin bioanalytical method has fulfilled the established criteria. It can, therefore, be used to determine warfarin concentration in saliva as an alternative method for TDM services in the clinical domain.

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Spectrofluorometric Analysis of New-Generation Antidepressant Drugs in Pharmaceutical Formulations, Human Urine, and Plasma Samples

Spectroscopy An International Journal ◽

10.1155/2012/567207 ◽

2012 ◽

Vol 27 ◽

pp. 59-71 ◽

Cited By ~ 4

Author(s):

Ruchita S. Das ◽

Y. K. Agrawal

Keyword(s):

Selective Serotonin Reuptake Inhibitors ◽

Good Accuracy ◽

Biological Fluids ◽

Antidepressant Drugs ◽

Pharmaceutical Formulations ◽

Plasma Samples ◽

Limit Of Quantification ◽

Accuracy And Precision ◽

New Generation

Spectrofluorometric analysis for the quantification of new-generation antidepressant drugs belong to the class of selective serotonin reuptake inhibitors and selective norepinephrine reuptake inhibitors is described. Five different drugs, sertraline, paroxetine, citalopram, venlafaxine, and fluoxetine, were analysed for spectrofluorometric detection in pharmaceutical formulations and urine and plasma samples. The calibration curves were found linear between fluorescence intensity and drugs concentration in the range of 5–500 ng/L with coefficients of determination above 0.9985 for all the analytes. The method recoveries were higher than 85% in all the three matrices. The intra- and interday variation coefficients were observed less than 8% and 13%, respectively. The limits of detection (LOD) and limit of quantification (LOQ) were found in the range of 0.016–0.084 ng/L and 0.090–0.285 ng/L, respectively. Additionally, the results were compared statistically for each analyte in all the three matrices and were found equivalent, which signifies the absence of matrix effect. Thus, the method will be applied successfully to the determination of the cited drugs in pure or dosage forms as well as in biological fluids with good accuracy and precision.

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Gas-chromatographic quantitation of theophylline in small volumes of plasma.

Clinical Chemistry ◽

10.1093/clinchem/22.6.898 ◽

1976 ◽

Vol 22 (6) ◽

pp. 898-900 ◽

Cited By ~ 12

Author(s):

D Perrier ◽

E Lear

Keyword(s):

Coefficient Of Variation ◽

Plasma Concentrations ◽

Plasma Samples ◽

Ionization Detector ◽

Liquid Chromatograph ◽

Blood Samples ◽

Rapid Procedure ◽

Flame Ionization ◽

Heel Prick

Abstract We describe a rapid procedure for quantitating theophylline in 100-mul plasma samples by use of a gas-liquid chromatograph equipped with a flame ionization detector. This methos is especially useful for monitoring theophylline concentrations in serum or plasma of infants, because sufficiently large blood samples can be readily obtained from a heel prick. The method is specific for theophylline in the presence of caffeine, theobromine and phenobarbital. For plasma concentrations equal to or greater than 5 mg/liter the average daily coefficient of variation was less than 7% while the coefficient of variation from day to day was less than 11%. The same approach can also be used to measure concentrations of phenobarbital in small volumes of plasma or serum, and is readily adapted to determination of theophylline and phenobarbital in larger samples.

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Development of a UPLC–MS/MS method for determination of a dual EZH1/2 inhibitor UNC1999 in rat plasma

Bioanalysis ◽

10.4155/bio-2021-0227 ◽

2021 ◽

Author(s):

Chunling Zhou ◽

Aiping He ◽

Qiang Kang ◽

Chensen Li ◽

Tianzhu Liu ◽

...

Keyword(s):

Good Accuracy ◽

Matrix Effects ◽

Pharmacokinetic Profile ◽

Rat Plasma ◽

Precipitation Method ◽

Plasma Samples ◽

Dual Inhibitor ◽

Accuracy And Precision ◽

Ionization Mode

Aim: We aimed to establish and validate a simple and sensitive UPLC–MS/MS method for the determination of UNC1999, a dual inhibitor against EZH1 and EZH2 in plasma samples. Materials & methods: UNC1999 in rat plasma was processed with protein precipitation method and then separated on a C18 column and detected under positive ionization mode. The method presented good linearity over the range of 1.0–2000 ng/ml with good accuracy and precision. UNC1999 was absorbed slowly and achieved a maximum concentration of 118.8 ± 12.0 ng/ml 1.5 h after oral administration. Conclusion: The method provides a favorable character in selectivity, linearity, accuracy, precision, recovery, matrix effects and stabilities and was suitable for describing the pharmacokinetic profile of UNC1999.

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Fluorometric Determination of Histamine in Tuna: Development of Method

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/60.5.1125 ◽

1977 ◽

Vol 60 (5) ◽

pp. 1125-1130 ◽

Cited By ~ 2

Author(s):

Walter F Staruszkiewicz ◽

Ellen M Waldron ◽

John F Bond

Keyword(s):

Anion Exchange ◽

Exchange Resin ◽

Anion Exchange Resin ◽

Colorimetric Method ◽

New Method ◽

Fluorometric Method ◽

Fluorometric Determination ◽

Chromatographic Separations ◽

Accuracy And Precision

Abstract Tuna extracts are treated with an anion exchange resin to remove interfering materials, histamine is derivatized with o-phthalaldehyde, and the fluorescence of the resulting compound is measured fluorometrically. Replicate analyses of acceptable and decomposed tuna packed in oil or water agreed within 1 mg at a level of 10 mg/100 g and within 12 mg at a level of 100 mg/100 g. Recoveries of histamine added to fish were >90 and >83% at levels of 10 and 100 mg/100 g, respectively. The new method is more rapid and specific and is simpler than previous methods because no liquid-liquid extractions or chromatographic separations of histamine are required. The sensitivity of the method allows quantitation of <10 mg histamine/100 g sample. The accuracy and precision of the fluorometric method are comparable to those of the official AOAC colorimetric method.

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Development and validation of a HPLC-UV method for the quantification of antiepileptic drugs in dried plasma spots

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2014-0472 ◽

2015 ◽

Vol 53 (3) ◽

Cited By ~ 25

Author(s):

Sara Baldelli ◽

Dario Cattaneo ◽

Luciana Giodini ◽

Lorena Baietto ◽

Giovanni Di Perri ◽

...

Keyword(s):

Antiepileptic Drugs ◽

High Performance ◽

Therapeutic Drug ◽

Plasma Samples ◽

Technical Problems ◽

Percentage Difference ◽

Accuracy And Precision ◽

Epileptic Patients ◽

Development And Validation

AbstractTherapeutic drug monitoring (TDM) of antiepileptic drugs is widely used in clinical practice to optimise therapy, but it is limited by technical problems and cost considerations. The aim of the present study was: 1) to validate a chromatographic method for the concomitant determination of levetiracetam, lamotrigine, ethosuximide, felbamate, rufinamide, zonisamide and monohydroxycarbamazepine; 2) to develop it for dried plasma spot (DPS) assessing its reliability against the classical determination from plasma; and 3) test its clinical application.Extraction of plasma samples and DPS was done by simple precipitation. Chromatographic analysis was performed using high performance liquid chromatography with ultraviolet detection. After validation, both methods were applied for the quantification of plasma samples from patients on antiepileptic therapy.Mean inter- and intra-day accuracy and precision were <15% for all compounds both in plasma and in DPS samples. DPS samples were considered stable under tested conditions. Measurements between plasma and DPS samples appeared related (p<0.0001). Bland-Altman analysis revealed accordance in lamotrigine values with mean overestimation of concentration for DPS sample of 2.8%. Also for monohydroxycarbamazepine data the agreement was acceptable (mean overestimation of 9.2%). For levetiracetam mean difference was 7.6%, while for ethosuximide mean percentage difference was 20.6%.The developed methods simplify TDM of antiepileptic drugs. This is particularly relevant for the method on dried spot sample devices because it facilitates further sample handling, stability and shipments making the management of therapies in epileptic patients easier also in hospitals devoid of a dedicated laboratory.

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