Person: TIRIS, GİZEM
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Publication Metadata only A review of the currently developed analytical methods for the determination of biogenic amines in food products(2023-01-01T00:00:00Z) TIRIS, GİZEM; Sare Yanıkoğlu, RABİA SARE; Ceylan, Burhan; EGELİ, DERYA; Kepekci Tekkeli, Evrim; ÖNAL, Armağan; TIRIS, GİZEM; YANIKOĞLU, RABİA SARE; EGELİ, DERYA© 2022Biogenic amines (BAs) are group of substances that are formed from amino acids by decarboxylation or amination and transamination of aldehydes and ketones. They may have either aliphatic, aromatic or heterocyclic structure. Their quantity determines their effects, optimum amounts are essential for physiological functions, but excess of BAs causes various toxic effects through out human body. BAs are presented in a wide variety of fermented foods such as fish, meat, milk products and some kinds of beverages like wine, beer and some fruit juices. In order to quantify their intake by food products are important, the methods that provide determination of BAs in food products are a matter of priority. Mostly, liquid chromatographic (LC) methods are preffered. Their amine groups are able to be derivatized by so many fluorogenic reagents. It is possible to combine LC systems with UV–vis. absorption spectrometric, fluorimetric and mass spectrometric detectors. Due to the fact that BAs are important markers for food quality and important for health, in this article LC methods for the determination of BAs in foods were reviewed from 2012 to present.Publication Metadata only AN UPLC METHOD FOR THE DETERMINATION OF SORAFENIB IN HUMAN PLASMA BY FLUORIMETRIC DETECTION WITH PRE-COLUMN DERIVATIZATION AND APPLICATION TO A PHARMACOKINETIC STUDY(2022-01-01T00:00:00Z) TIRIS, GİZEM; Tekkeli, S. Evrim Kepekci; Önal, Cem; Ceylan, Burhan; ÖNAL, Armağan; TIRIS, GİZEM© 2022, Publishing House of the Romanian Academy. All rights reserved.This research presents a new, sensitive and selective UPLC method with fluorometric detection for the determination of sorafenib in human plasma and application of the method to a pharmacokinetic study. Sorafenib was precolumn derivatized with 7-chloro-4-nitrobenzofurazan (NBD-Cl) and the separation of the fluorescent derivative was performed with a C18 column (50 mm x 2.1 mm, 1.7 µm) at 40ºC using a mobile phase composed of acetonitrile-0.1% trifluoroacetic acid in water (60:40, v/v) by isocratic elution with flow rate of 0.5 mL min−1. The injection volume was 7 µL. The method depends on the measurement of the derivative using fluorescence detection (λex = 398 nm, λem = 425 nm). The retention time of sorafenib was 3.10 ± 0.02 min. The novel method was validated in accordance with ICH criteria by studying on the parameters such as specificity, linearity, precision, accuracy and robustness. The method was determined to be linear in a concentration range of 0.25-10 µg mL−1 with the correlation coefficient of 0.9995. Limit of detection and quantitation were found to be 0.075 and 0.25 µg mL−1, respectively. Intraday and interday RSD values were less than 5.48%. The plasma concentration–time profile and pharmacokinetic parameters such as AUC0–t, AUC0–∞, Cmax, tmax, t1/2 were measured according to the assays. The proposed method is feasible to investigate the bioequivalence and bioavailability and routine analysis of the drug in plasma.Publication Metadata only A New HPLC Method with UV Detection for the Determination of Carnosol in Human Plasma and Application to a Pharmacokinetic Study(2021-09-01T00:00:00Z) TEKKELİ, ŞERİFE EVRİM; Ceylan, Burhan; TIRIS, GİZEM; TIRIS, GİZEM; TEKKELİ, ŞERİFE EVRİMThis article aims to present a simple and sensitive, HPLC-UV method, which was developed to determine carnosol in human plasma samples. Chromatographic separation was achieved with C18 column (150 mm x 4.6 mm x 5 mu m), at 25 degrees C with gradient elution of the mobile phase consisting of methanol-water (2% o-phosphoric acid) at flow rate 1.2 mL/min. The analyte was detected at 230 nm by UV detector. The retention time of carnosol is 3.40 +/- 0.01 min. This currently developed method was validated according to ICH criteria by evaluating the specificity, linearity, precision, accuracy and robustness. The method was determined to be linear in a concentration range of 1-20 ng/mL with the correlation coefficient of 0.9942. The proposed method was applied successfully to the analysis of carnosol in spiked human plasma with good recovery as 96.4% and the precision of the method was determined by intra day and interday assays with the highest RSD % values 5.71. The method successfully applied to a pharmacokinetic study with determination of C-max, t(max), t(1/2) and AUC, by administration of carnosol to a healthy volunteer.