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TIRIS, GİZEM

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GİZEM

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TIRIS

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Start date: 2020End date: 2020Item Type: Publication

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Now showing 1 - 5 of 5
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    A new HPLC method for the determination of Allicin and S-Allyl cysteine in garlic (Allium sativum L.) extracts
    (2020-09-01T00:00:00Z) BUCAK, Seden; TEKKELİ, ŞERİFE EVRİM; CEYLAN, BURHAN; TIRIS, GİZEM; TEKKELİ, ŞERİFE EVRİM; TIRIS, GİZEM
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    Novel approaches for determination of antiretroviral reverse transcriptase inhibitor agent in commercial dosage forms by using spectrofluorimetric, first derivative spectrophotometric, and HPLC methods
    (2020-09-01T00:00:00Z) Tiris, Gizem; Ciloglu, Emine; ERK, NEVİN; TIRIS, GİZEM
    Background: Rapid, simple, and sensitive spectrofluorimetric, first derivative spectrophotometric, and high-performance liquid chromatographic (HPLC) methods have been developed and validated for determination of tenofovir in pharmaceutical preparations. Spectrofluorimetric method is based on measuring the native fluorescence intensity of tenofovir at 375.0 nm after excitation at 275.0 nm. Calibration graphics were plotted and were found linear over 4.72-15.75 mu g/mL concentration range (r(2)= 0.9994). The second method developed was the first derivative spectrophotometric method for the analysis of tenofovir performed by measuring the amplitude at 251.7 and 272.6 nm. Linearity was observed in the concentration range 10.0-28.0 mu g/mL (r(2)= 0.9998). On the other hand, HPLC with a diode array detector (DAD). Ritonavir was used as internal standard (IS). HPLC analysis was carried out on a C(18)column (Wakosil-II 5 C-18 AR, 4.6 x 250 mm) using a mobile phase consisting of acetonitrile: 0.5% formic acid (99.5:0.5; v/v) at a flow rate of 1.0 mL/min. Injection volume was 5.0 mu L. DAD signals at 260.0 nm were used. HPLC method was found to be linear over the concentration range of 10.0-100.0 mu g/mL (r(2)= 0.9990).
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    A novel stability-indicating method for determination of a new antidepressant effect of vortioxetine in a pharmaceutical formulation by using RP-HPLC
    (2020-12-01T00:00:00Z) TIRIS, GİZEM; Alver, Cansu; ERK, NEVİN; TIRIS, GİZEM
    Background: A novel rapid, accurate, and stability-indicating reversed-phase high performance liquid chromatographic (RP-HPLC) and first derivative spectrophotometric determination were explained for the assay of vortioxetine (VRT) in bulk and pharmaceutical formulations. For RP-HPLC method, optimal separation and determination of VRT were achieved with a Waters Symmetry C-18, (100 x 4.6 mm, 3.5 mu m) analytical column using a mobile phase consisting of methanol:0.05 M potassium dihydrogen phosphate (pH:3.0 +/- 0.05) (30:70, v/v) in isocratic mode with flow rate of 1.3 mL min(-1). Injection volume was 20 mu L. The maximum absorption wavelength of VRT is 225.0 nm; hence, 225.0 nm was studied as the detection wavelength and column at 50 degrees C temperature. The caffeine was used as the internal standard (IS). On the other hand, the first derivative spectrophotometric method for the analysis of vortioxetine was performed by measuring the amplitude at 251.7 and 272.6 nm.
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    Analytical tools for greenness assessment of chromatographic approaches: Application to pharmaceutical combinations of Indapamide, Perindopril and Amlodipine
    (2020-12-01T00:00:00Z) Saleh, Sarah S.; Lotfy, Hayam M.; Tiris, GİZEM; Erk, Nevin; Rostom, Yasmin; TIRIS, GİZEM
    The green profile of the proposed method was assessed and compared with reported classical methods via four tools of greenness which are: Eco-Scale, National Environmental Methods Index (NEMI), Assessment of Green Profile (AGP) and Green Analytical Procedure Index (GAPI). A simple, precise and rapid (RP-HPLC) has been developed for the quantification of Indapamide (IND), perindopril (PER) arginine and amlodipine besylate (ADB) in binary and ternary mixtures. A greener alternate RP-HPLC method was presented for the determination of pharmaceutical combinations composed of the cited medications using an eco-friendly eluent and quick run time with the least waste yield. Chromatographic separation was achieved using Waters Spherisorb ODS-2 C18 column (150 x 4.6 mm, i.d., 5 mu m) and eluent formed of acetonitrile : phosphate buffer (20 mM, pH = 3): methanol in the ratio of (65: 30: 5, by volume) at flow rate 1.0 mL/min with DAD-detection at 220 nm. This procedure was valid over linearity ranges of 0.5-20 mu g/mL, 2.5-40 mu g/mL and 2-40 mu g/mL for IND, PER and AML, respectively. The presented chromatographic method was completely validated regarding ICH guidelines and were statistically compared with those of the reported methods applying t-test and F-test at 95% confidence. The proposed method was found to be greener in terms of usage of hazardous chemicals and solvents, energy consumption, and waste production.
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    Determination of dihydrocapsaicin adulteration in dietary supplements using LC-MS/MS
    (2020-01-01T00:00:00Z) DİNCEL, DEMET; Olgan, Hatice; Canbaloglu, Zeynep; Yalcin, Sule; Erkucuk, Aysen; TIRIS, GİZEM; GÖREN, AHMET CEYHAN; DİNCEL, DEMET; TIRIS, GİZEM; GÖREN, AHMET CEYHAN
    Adulterations of dietary supplements are serious threats to public health in all around of world. Nowadays, in order to obtain the intended effect from natural remedies, the adulteration of natural products via artificial or harmful chemicals are increasing. A rapid LC-MS/MS method for determination of capsaicin and dihydrocapsaicin in dietary supplements via Fortis C18 (150 x 3 mm; 3 mu m) column at 25 degrees C was developed and validated in a mixture of mobile phase A (1 % formic acid solution and 0.1 % ammonium formate in water) and B (1 % formic acid solution and 0.1 % ammonium formate in methanol) with gradient program at a flow rate of 0.35 mL/min. The recoveries of developed methods weytre obtained in the range of % 95.4-106.3 for capsaicin and % 96.3-108.9 for dihydrocapsaicin. This study shows that synthetic compound dihydrocapsaicin is widely use in dietary supplements products for adulteration to increase the effects of product without any declaration.