TY - JOUR A1 - Ozcelikay, Goksu A1 - Kurbanoglu, Sevinc A1 - Yarman, Aysu A1 - Scheller, Frieder W. A1 - Ozkan, Sibel A. T1 - Au-Pt nanoparticles based molecularly imprinted nanosensor for electrochemical detection of the lipopeptide antibiotic drug Daptomycin JF - Sensors and actuators : B, Chemical N2 - In this work, a novel electrochemical molecularly imprinted polymer (MIP) sensor for the detection of the lipopeptide antibiotic Daptomycin (DAP) is presented which integrates gold decorated platinum nanoparticles (Au-Pt NPs) into the nanocomposite film. The sensor was prepared by electropolymerization of o-phenylenediamine (o-PD) in the presence of DAP using cyclic voltammetry. Cyclic voltammetry and differential pulse voltammetry were applied to follow the changes in the MIP-layer related to rebinding and removal of the target DAP by using the redox marker [Fe(CN)(6)](3-/4-). Under optimized operational conditions, the MIP/Au-Pt NPs/ GCE nanosensor exhibits a linear response in the range of 1-20 pM towards DAP. The limit of detection and limit of quantification were determined to be 0.161pM +/- 0.012 and 0.489pM +/- 0.012, respectively. The sensitivity towards the antibiotics Vancomycin and Erythromycin and the amino acids glycine and tryptophan was below 7 percent as compared with DAP. Moreover, the nanosensor was also successfully used for the detection of DAP in deproteinated human serum samples. KW - molecularly imprinted polymer KW - Daptomycin KW - platinum nanoparticles KW - gold KW - nanoparticles KW - modified electrodes Y1 - 2020 U6 - https://doi.org/10.1016/j.snb.2020.128285 SN - 0925-4005 VL - 320 PB - Elsevier Science CY - Amsterdam ER - TY - JOUR A1 - Yarman, Aysu A1 - Scheller, Frieder W. T1 - How reliable is the electrochemical readout of MIP sensors? JF - Sensors N2 - Electrochemical methods offer the simple characterization of the synthesis of molecularly imprinted polymers (MIPs) and the readouts of target binding. The binding of electroinactive analytes can be detected indirectly by their modulating effect on the diffusional permeability of a redox marker through thin MIP films. However, this process generates an overall signal, which may include nonspecific interactions with the nonimprinted surface and adsorption at the electrode surface in addition to (specific) binding to the cavities. Redox-active low-molecular-weight targets and metalloproteins enable a more specific direct quantification of their binding to MIPs by measuring the faradaic current. The in situ characterization of enzymes, MIP-based mimics of redox enzymes or enzyme-labeled targets, is based on the indication of an electroactive product. This approach allows the determination of both the activity of the bio(mimetic) catalyst and of the substrate concentration. KW - molecularly imprinted polymers KW - electropolymerization KW - direct electron KW - transfer KW - catalysis KW - redox marker KW - gate effect Y1 - 2020 U6 - https://doi.org/10.3390/s20092677 SN - 1424-8220 VL - 20 IS - 9 PB - MDPI CY - Basel ER - TY - JOUR A1 - Kurbanoglu, Sevinc A1 - Yarman, Aysu T1 - Simultaneous determination of hydrochlorothiazide and irbesartan from pharmaceutical dosage forms with RP-HPLC T1 - Farmasötik Dozaj Formlarında TF-YPSK ile Hidroklorotiyazid ve İrbesartanın Eş Zamanlı Tayini JF - Turkish journal of pharmaceutical sciences N2 - Objectives: In this work, a simple and rapid liquid chromatographic method for the simultaneous determination of irbesartan (IRBE) and hydrochlorothiazide (HCT) was developed and validated by reverse phase high performance liquid chromatography (RP-HPLC).
Materials and Methods: Experimental conditions such as different buffer solutions, various pH values, temperature, composition of the mobile phase, and the effect of flow rate were optimized.
Results: The developed RP-HPLC method for these antihypertensive agents was wholly validated and IRBE was detected in the linear range of 0.1-25 mu g mL(-1) and HCT was detected in the linear range of 0.25-25 mu g mL(-1). Moreover, the suggested chromatographic technique was successfully applied for the determination of the drugs in human serum and pharmaceutical dosage forms with limit of detection values of 0.008 mu g mL(-1) for IRBE and 0.012 mu g mL(-1) for HCT.
Conclusion: The proposed rapid analysis method of these antihypertensive drugs can be easily used and applied by pharmaceutical companies for which the analysis time is important. N2 - Amaç: Bu çalışmada, irbesartan (IRBE) ve hidroklorotiyazidin (HCT) eşzamanlı tayini için basit ve hızlı bir ters fazlı yüksek performanslı sıvı kromatografisi (TF-YPSK) yöntemi geliştirilmiş ve validasyon çalışmaları yapılmıştır. Gereç ve Yöntemler: Deneysel koşullar; farklı tampon çözeltileri, çeşitli pH değerleri, sıcaklık, mobil fazın bileşimi, akış hızının etkisi gibi parametrelerin üzerinden optimize edildi. Bulgular: Bu antihipertansif ajanlar için geliştirilen TF-YPSK yönteminin tüm validasyon parametrelerine ilişkin çalışmalar yapılmış, ve IRBE 0,1-25 μg mL-1 doğrusal aralığında ve HCT 0,25-25 μg mL-1 doğrusal aralığında tespit edilmiştir. Ayrıca önerilen TF-YPSK yöntemi ile IRBE için 0,008 μg mL-1 ve HCT için 0,012 μg mL-1 tayin alt sınır değerleri bulunmuştur. Geliştirilen yöntem, insan serumunda ve farmasötik dozaj formlarında bulunan IRBE ve HCT’nin belirlenmesi için başarıyla uygulanmıştır. Sonuç: Bu antihipertansif ilaçların miktar tayininde önerilen YPSK analiz yönteminin, analiz süresinin önemli olduğu ilaç firmalarında rahatlıkla kullanılabileceği ve uygulanabileceği düşünülmektedir. KW - HPLC KW - irbesartan KW - hydrochlorothiazide KW - pharmaceutical dosage forms Y1 - 2020 U6 - https://doi.org/10.4274/tjps.galenos.2019.76094 SN - 1304-530X VL - 17 IS - 5 SP - 523 EP - 527 PB - Turkish Pharmacists Association CY - Çankaya-Ankara ER - TY - GEN A1 - Yarman, Aysu A1 - Scheller, Frieder W. T1 - How reliable is the electrochemical readout of MIP-sensors? T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - Electrochemical methods offer the simple characterization of the synthesis of molecularly imprinted polymers (MIPs) and the readouts of target binding. The binding of electroinactive analytes can be detected indirectly by their modulating effect on the diffusional permeability of a redox marker through thin MIP films. However, this process generates an overall signal, which may include nonspecific interactions with the nonimprinted surface and adsorption at the electrode surface in addition to (specific) binding to the cavities. Redox-active low-molecular-weight targets and metalloproteins enable a more specific direct quantification of their binding to MIPs by measuring the faradaic current. The in situ characterization of enzymes, MIP-based mimics of redox enzymes or enzyme-labeled targets, is based on the indication of an electroactive product. This approach allows the determination of both the activity of the bio(mimetic) catalyst and of the substrate concentration. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 960 KW - molecularly imprinted polymers KW - electropolymerization KW - direct electron transfer KW - catalysis KW - redox marker KW - gate effect Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-471608 SN - 1866-8372 IS - 960 ER -