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Öğe A novel core-shell-based chromatographic method supported by ratio derivative spectrophotometry for the simultaneous determination of perindopril, indapamide, and amlodipine ternary mixtures(TUBİTAK, 2018) Karadurmuş, Leyla; Gümüştaş, Mehmet; Kurbanoğlu, Sevinç; Uslu, Bengi; Özkan, Sibel AyşılIn this work, ratio spectra of the frst derivative spectrophotometric and liquid chromatographic methods have been described for the frst time for the simultaneous determination of perindopril (PER), indapamide (IND), and amlodipine (AML) in dosage forms. For chromatographic separations several mobile phase compositions were tested for efcient separation with the use of a new column technology related to superfcially porous particles. Optimum chromatographic separation was achieved using a Kinetex C18 column (150 × 4.6 mm I.D. 5 ?m) at a flow rate of 1.5 mL min-1. The separation was carried out at 30 ° C and the diode array detector was adjusted to 215 nm. As a comparison, a spectrophotometric method depending on the frst derivative of the ratio spectra was developed. The frst derivative of the ratio amplitudes at 227.2 nm for PER, 269.4 nm for AML, 292.0 nm for IND were selected. The proposed methods were successfully applied for the simultaneous assay of the drug combination in pharmaceutical dosage forms and the methods were compared to each other in terms of Student t and F tests for the comparison of their accuracy and precision parameters. © 2018 TUBITAK. All rights reserved.Öğe A sensitive and selective RP-LC method for the simultaneous determination of the antihypertensive drugs, enalapril, lercanidipine, nitrendipine and their validation(2013) Kurbanoğlu, Sevinç; Gümüştaş, Mehmet; Uslu, Bengi; Özkan, Sibel AyşılA RP-LC method is presented, which is sensitive and selective for the simultaneous determination of enalapril-lercanidipine and enalapril-nitrendipine binary mixtures in their pharmaceutical dosage forms. The analyte peaks were detected using the LC method with the mobile phase ratio of methanol: water (70:30 v/v, pH 3.0) and a 1.0 mL min-1 flow rate. The detection wavelength was selected at 210 nm using photo diode array detector and column temperature was optimized to 30 C. Linearity was obtained at different concentration ranges for all working pharmaceutically active compounds between 0.5 and 25 ?g mL-1. The proposed methods were extensively validated according to USP 27 requirements and ICH guidelines. The methods were applied to the analysis of pharmaceutical dosage forms containing binary mixtures of enalapril-lercanidipine and enalapril-nitrendipine. Moreover, the proposed methods were applied for the degradation studies of the selected compounds. Degradation studies were conducted using stress conditions such as UV light, acidic and alkaline hydrolysis, oxidation and heat in oven, to evaluate the ability of the separation of the response of standard compounds from their degradation products. © 2013 Springer-Verlag Berlin Heidelberg.Öğe A validated stability-indicating RP-LC method for the simultaneous determination of amlodipine and perindopril in tablet dosage form and their stress degradation behavior under ICH-recommended stress conditions(2013) Gümüştaş, Mehmet; Özkan, Sibel AyşılA stability-indicating RP-LC assay method was developed for the simultaneous determination of the cardiovascular drugs amlodipine and perindopril in the presence of degradation products generated from forced decomposition studies. The developed method is applicable for the determination of related substances in bulk drugs and simultaneous assay in a tablet pharmaceutical dosage form. Separation of the drugs and their degradation products was obtained using an RP Waters Spherisorb ODS1 column (250 × 4.6 mm id, 5 ?m particle size) with the mobile phase acetonitrile-water (30 + 70, v/v) containing 15 mM phosphoric acid. The pH of the mobile phase was adjusted to 5.0. A flow rate of 1.2 mL/min was used for the separations, with detection at 215 nm. The chromatographic separation was performed at a column temperature of 45°C. Atenolol was chosen as the internal standard. Amlodipine and perindopril were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. Degradation studies showed that both compounds were degraded under these stress conditions. The method was found to be stability-indicating and can be used for the routine analysis of amlodipine and perindopril in the studied combined tablet dosage form.Öğe Analytical and preparative scale separation of enantiomers of chiral drugs by chromatography and related methods(Bentham Science Publishers B.V., 2018) Gümüştaş, Mehmet; Özkan, Sibel Ayşıl; Chankvetadze, BezhanWhile the amino acids, enzymes and hormones are chiral, chirality plays significant role in the life of plants, animals, as well as the human being. Chirality of molecules is important in various industries, such as pharmaceutical, agricultural, food, electronics, etc. Chiral drugs may have different bioavailability, distribution, biotransformation and excretion, as well as quantitatively and/or qualitatively different pharmacological or toxic properties. Enantiomerically pure chiral drugs have been increasingly developed for the pharmaceutical market due to their superiority from the viewpoints of potency and safety. This is supported by the development of new methods for enantioselective production of the chiral compounds, as well as by the capability of the enantioselective analytical methods to allow a detection and quantification of minor enantiomeric impurity in the presence of another enantiomer in a large excess. The aim of the present review is to provide a short summary of the basic principles of chiral separations on an analytical and preparative scale. In addition, some selected applications for analytical techniques, such as gas chromatography, supercritical fluid chromatography, high performance liquid chromatography, capillary electrophoresis and capillary electrochromatography for the separation of enantiomers of chiral pharmaceuticals published in the last two years are also discussed. © 2018 Bentham Science Publishers.Öğe Determination of pK a values of cefdinir and cefixime by LC and spectrophotometric methods and their analysis in pharmaceutical dosage forms(Friedr. Vieweg und Sohn Verlags GmbH, 2011) Şanlı, Nurullah; Şanlı, Senem; Sızır, Ümit; Gümüştaş, Mehmet; Özkan, Sibel AyşılThe pK a values of cefdinir and cefixime, which are used in the treatment of bacterial infections, have been determined precisely in water and methanol-water binary mixtures (20% v/v) using spectrophotometric titration and LC, respectively. A simple, fast and precise isocratic high-performance liquid chromatographic (LC) procedure has been developed for the determination of cefdinir and cefixime in drug formulations. This method was validated successfully for specificity, precision, linearity, range, accuracy, limit of detection, and limit of quantitation as per the ICH guidelines. The proposed method can be used for routine analysis of studied cephalosporin compounds and as an alternative tool for drug quality control laboratories. © 2011 Springer-Verlag.Öğe Determination of pKa values of some antihypertensive drugs by liquid chromatography and simultaneous assay of lercanidipine and enalapril in their binary mixtures(Elsevier B.V., 2010) Gümüştaş, Mehmet; Şanlı, Senem; Şanlı, Nurullah; Özkan, Sibel AyşılIn this study, pKa values were determined using the dependence of the retention factor on the pH of the mobile phase for three ionizable substances, namely, enalapril, lercanidipine and ramipril (IS). The effect of the mobile phase composition on the ionization constant was studied by measuring the pKa at different methanol-water mixtures, ranging between 50 and 65% (v/v), using LC-DAD method. Two simple, accurate, precise and fully validated analytical methods for the simultaneous determination of enalapril and lercanidipine in combined dosage forms have been developed. Separation was performed on an X-Terra RP-18 column (250 mm × 4.60 mm ID × 5 ?m) at 40 °C with the mobile phase of methanol-water 55:45 (v/v) adjusted to pH 2.7 with 15 mM orthophosphoric acid. Isocratic elution was performed in less than 12 min with a flow rate of 1.2 mL min-1. Good sensitivity for the analytes was observed with DAD detection. The LC method allowed quantitation over the 0.50-20.00 ?g mL-1 range for enalapril and lercanidipine. The second method depends on first derivative of the ratio-spectra by measurements of the amplitudes at 219.7 nm for enalapril and 233.0 nm for lercanidipine. Calibration graphs were established for 1-20 ?g mL-1 for enalapril and 1-16 ?g mL-1 lercanidipine, using first derivative of the ratio spectrophotometric method. Both methods have been extensively validated. These methods allow a number of cost and time saving benefits. The described methods can be readily utilized for analysis of pharmaceutical formulations. The methods have been applied, without any interference from excipients, for the simultaneous determination of these compounds in tablets. There was no significant difference between the performance of the proposed methods regarding the mean values and standard deviations. © 2010 Elsevier B.V. All rights reserved.Öğe Development and validation of a liquid chromatographic method for concurrent assay of weakly basic drug verapamil and amphoteric drug trandolapril in pharmaceutical formulations(2012) Gümüştaş, Mehmet; Şanlı, Senem; Şanlı, Nurullah; Özkan, Sibel AyşılThe analysis of weakly basic drugs such as verapamil by reverse-phase liquid chromatography remains a problem, particularly when present in combination with other drugs such as amphoteric compounds like trandolapril. In this study, the simple, accurate, precise and fully validated RP-LC method for the simultaneous determination of verapamil and trandolapril in combined dosage forms has been developed. The LC method allowed quantitation over the ranges of 0.50-18.00 ?g/mL and 0.05-1.00 ?g/mL for verapamil and trandolapril, respectively. The detection limits were found to be 0.008 ?g/mL and 0.018 ?g/mL for verapamil and trandolapril, respectively. Moreover, pKa values of verapamil and trandolapril were determined via the dependence of the retention factor on the pH of the mobile phase for ionizable substances. The effect of the mobile phase composition on the ionization constant was studied by measuring the pKa at different methanol-water mixtures, ranging 50-65% (v/v). It was shown that RP-HPLC was suitable for the high throughput analysis of the combination of verapamil and trandolapril. The method also allows a number of cost and time saving benefits and can be readily employed for the analysis of pharmaceutical formulations. The method has been verified, without any interference from excipients, for the concurrent analysis of these compounds in tablets.Öğe Development and validation of a stability-indicating RP-LC method for the determination of anticancer drug epirubicin in pharmaceuticals(Taylor and Francis Inc., 2014) Kurbanoğlu, Sevinç; Bozal Palabıyık, Burçin; Gümüştaş, Mehmet; Şanlı, Senem; Uslu, Bengi; Özkan, Sibel AyşılIn the present paper, sensitive, rapid, and different analytical methodology was developed for the determination of anticancer drug epirubicin (EPR). The mixture of epirubicin and moxifloxacin as internal standard was separated on a reversed phase Waters Spherisorb ODS1 column (250mm × 4.6mm × 5mm) using acetonitrile/water (30:70 v/v) mixture containing 15 mM phosphoric acid as mobile phase at 0.6 mL min-1 flow rate and 30 C. Also degradation studies were conducted as stress conditions of UV light, acidic hydrolysis, alkaline hydrolysis, oxidation, and heat in oven (100°C), to evaluate the ability of the proposed method for the separation of EPR from its degradation products. The validated method suggests routine analysis of EPR in differently equipped laboratories. © 2014 Copyright Taylor & Francis Group, LLC.Öğe Development of a HILIC method for the determination of 5-fluorouracil from nano drug delivery systems and rat skin extracts(Elsevier B.V., 2018) Amasya, Gülin; Gümüştaş, Mehmet; Badıllı, Ulya; Özkan, Sibel Ayşıl; Tarımcı, NilüferThis is the first report in literature using hydrophilic interaction liquid chromatography (HILIC) in combination with diode array detector (DAD) for stability indicating determination of 5-Fluorouracil (5-FU) from its bulk form, pharmaceutical preparations, developed solid lipid nanoparticle (SLN) and nano structured lipid carrier (NLC) drug delivery systems as well as the rat skin extracts. The separation was performed at 45 °C, on Sequant Zic HILIC (250 mm × 4.60 mm ID, 5 ?m, 200 Ao), peek HPLC column. Mobile phase is consisting of a mixture of acetonitrile: buffer containing 5 mM ammonium acetate (95:5; v/v). The pH of the mobile phase was adjusted to 7.0 using 1 M NaOH. The analysis was carried out at 0.75 mL min?1 flow rate with a detection wavelength of 265 nm and the injection volume was arranged as 10 ?L. The developed method was fully validated in accordance with the International Council on Harmonization (ICH) Guidelines. Specificity of this method was demonstrated by forced degradation studies. As a result of calibration studies, the calibration curve was found linear in the concentration range of 1–250 ?g mL-1 (R2 = 0.999). The precision of this technique calculated within the frame of intra-day and inter-day based on a percentage of relative standard deviation (RSD%) values (<2%). The limits of detection and quantification were 11 and 37 ng mL-1 respectively. On the other hand, 5-FU loaded SLN and NLC formulations with average particle size of 370 nm were also developed and compared in order to increase the permeation of drug into the rat skin. Ex-vivo Penetration/Permeation Studies indicated that higher dermal accumulation of 5-FU was obtained with NLC formulation. As a conclusion, the present work expressed the optimization and the validation of a selective, simple, precise and accurate fully validated HILIC method with sufficient sensitivity for the estimation of 5-FU in raw materials, marketed formulation and rat skin extract after applying both of the commercial product and newly developed nanoparticulate drug delivery systems on to the rat skins with high percentage recoveries. © 2018 Elsevier B.V.Öğe Electroanalytical characteristics of antipsychotic drug ziprasidone and its determination in pharmaceuticals and serum samples on solid electrodes(Elsevier B.V., 2010) Kul, Dilek; Gümüştaş, Mehmet; Uslu, Bengi; Özkan, Sibel AyşılZiprasidone is a psychotropic agent used for the treatment of schizophrenia. Its oxidation was investigated electrochemically at boron-doped diamond and glassy carbon electrodes using cyclic, differential pulse, and square wave voltammetry. The dependence of the peak current and peak potentials on pH, concentration, nature of the buffer, and scan rate were examined. The process was diffusion and adsorption controlled for boron-doped diamond and glassy carbon electrodes, respectively. The possible mechanism of oxidation was discussed with some model compounds that have indole and piperazine oxidations. A linear response was obtained between 8 × 10-7 and 8 × 10-5 M for the first peak in acetate buffer (pH 5.5) and between 2 × 10-6 and 2 × 10-4 M for the second peak in 0.1 M H2SO4 with boron-doped diamond electrode for differential pulse and square wave voltammetric techniques. The reproducibility and accuracy of the proposed methods were found between 0.31 and 1.20, 99.27 and 100.22, respectively. The recovery studies were also achieved to check selectivity and accuracy of the methods. The proposed methods were applied for the determination of ziprasidone from pharmaceutical dosage forms and human serum samples without any time-consuming extraction, separation, evaporation or adsorption steps prior to drug assay except precipitation of the proteins using acetonitrile. The results were statistically compared with those obtained through an established LC-UV technique, no significant differences were been found between the voltammetric and LC methods. © 2010 Elsevier B.V. All rights reserved.Öğe Electrochemical approach for the sensitive determination of anticancer drug epirubicin in pharmaceuticals in the presence of anionic surfactant(Editions de l'Academie Republique Populaire, 2013) Bozal Palabıyık, Burçin; Kurbanoğlu, Sevinç; Gümüştaş, Mehmet; Uslu, Bengi; Özkan, Sibel AyşılIn this research, sensitive, rapid, different electrochemical methods were developed for the determination of anticancer drug epirubicin. The aim of the study was to fully validated determination of epirubicin in pharmaceuticals, by means of electroanalytical methods. The detailed electrooxidative behavior of epirubicin was investigated using cyclic, differential pulse and square wave voltammetry at boron-doped diamond electrode. The possible oxidation mechanism was discussed. Surfactant effect was also examined using 1×10-3 M sodium dodecyl sulphate. The oxidation process was found nearly irreversible over the pH range studied and exhibited diffusion controlled electrode process. All experimental parameters have been optimized and the following studies were realized under the optimum conditions. The sensor used in this research is suitable for the analysis of the trace amounts of epirubicin in pharmaceuticals. The proposed methods were applied to commercial preparations and average percentage recovery was in good agreement between each other (differential pulse and square wave voltammetry).Öğe Electrochemical evaluation and determination of antiretroviral drug fosamprenavir using boron-doped diamond and glassy carbon electrodes(2010) Gümüştaş, Mehmet; Özkan, Sibel AyşılFosamprenavir is a pro-drug of the antiretroviral protease inhibitor amprenavir and is oxidizable at solid electrodes. The anodic oxidation behavior of fosamprenavir was investigated using cyclic and linear sweep voltammetry at boron-doped diamond and glassy carbon electrodes. In cyclic voltammetry, depending on pH values, fosamprenavir showed one sharp irreversible oxidation peak or wave depending on the working electrode. The mechanism of the oxidation process was discussed. The voltammetric study of some model compounds allowed elucidation of the possible oxidation mechanism of fosamprenavir. The aim of this study was to determine fosamprenavir levels in pharmaceutical formulations and biological samples by means of electrochemical methods. Using the sharp oxidation response, two voltammetric methods were described for the determination of fosamprenavir by differential pulse and square-wave voltammetry at the boron-doped diamond and glassy carbon electrodes. These two voltammetric techniques are 0.1 M H2SO4 and phosphate buffer at pH 2.0 which allow quantitation over a 4×10-6 to 8×10 -5 M range using boron-doped diamond and a 1×10-5 to 1×10-4 M range using glassy carbon electrodes, respectively, in supporting electrolyte. All necessary validation parameters were investigated and calculated. These methods were successfully applied for the analysis of fosamprenavir pharmaceutical dosage forms, human serum and urine samples. The standard addition method was used in biological media using boron-doped diamond electrode. No electroactive interferences from the tablet excipients or endogenous substances from biological material were found. The results were statistically compared with those obtained through an established HPLC-UV technique; no significant differences were found between the voltammetric and HPLC methods. © 2009 Springer-Verlag.Öğe Erratum to: UPLC versus HPLC on drug analysis: advantageous, applications and their validation parameters(2013) Gümüştaş, Mehmet; Kurbanoğlu, Sevinç; Uslu, Bengi; Özkan, Sibel AyşılThe authors would like to call the reader’s attention to the fact that unfortunately there were several references faultily assigned in Table 1.Öğe Fully validated simultaneous determination of bisoprolol fumarate and hydrochlorothiazide in their dosage forms using different voltammetric, chromatographic, and spectrophotometric analytical methods(2013) Bozal Palabıyık, Burçin; Gümüştaş, Mehmet; Doğan Topal, Burcu; Uslu, Bengi; Özkan, Sibel AyşılVoltammetric, chromatographic, and spectrophotometric methods were developed for the simultaneous determination of bisoprolol fumarate (BIS) and hydrochlorothiazide (HCZ). Differential pulse and square wave voltammetry techniques were used to analyze BIS and HCZ simultaneously by measuring at about 1400 and 1100 mV, respectively. RP-HPLC was the second method for simultaneous analysis of the compounds. The mixture of BIS, HCZ, and moxifloxacin as an internal standard was separated on an RP Zorbax Eclipse XDB-C18 column (150 × 4.6 mm, id, 5 ?m particle size) using acetonitrile-15 mM phosphate (25 + 75, v/v) mobile phase at a 1.0 mL/min flow rate. The third method was based on first derivative of the ratio-spectra method obtained from the measurements of the amplitudes at 246 and 257 nm for BIS and HCZ, respectively. All the proposed methods were effectively applied for the simultaneous determination of BIS and HCZ in tablet dosage forms without any time-consuming extraction, sample preparation, or derivatization procedures.Öğe Fulvestrant-loaded polymer-based nanoparticles for local drug delivery: Preparation and in vitro characterization(Editions de Sante, 2017) Hasçiçek, Canan; Şengel Türk, Ceyda Tuba; Gümüştaş, Mehmet; Özkan, Sibel Ayşıl; Bakar, Filiz; Daş Evcimen, Net; Savaşer, Ayhan; Özkan, YalçınThe present investigation was aimed at optimizing Fulvestrant (FLV)-loaded nanoparticulate formulations to overcome side effects caused by the intramuscular injection of FLV, and to prolong local intratumoral action at high drug concentration. Novel poly(ethylene glycol) (PEG) conjugated poly(ethylene glycol)-block-poly(lactide-co-glycolide) (PEG-b-PLGA), and poly(ethylene glycol)-block-poly(?-caprolactone) (PEG-b-PCL) nanoparticles were used as the drug-loading vehicles. The influence of hydrophobicity of the two different polymeric materials based nanoparticles was investigated with respect to in vitro properties, cytotoxic capacity and cell uptake potency. The sphere-shaped nanoparticles ranged between 84.56 and 220.20 nm, had negative surface charges, and exhibited sustained release profiles. In-vitro cytotoxicity results demonstrated that nanoparticles prepared with the higher hydrophilic form of PEG-b-PCL, a diblock copolymer composition, exerted the highest inhibitory effect on the proliferation of MCF-7 cells and significantly increased the intracellular uptake, compared to free FLV and the other tested polymer-based formulations. The final data of this research indicated that polymer hydrophobicity was a key to improving the major characteristics, especially anti-proliferative activity of the developed polymer-based nanoparticles. The drug delivery systems formulated here are promising nanocarriers for FLV delivery and have potential for the treatment of hormone-dependent breast cancers. © 2017 Elsevier B.V.Öğe Gemifloksasin'in Farmasötik Dozaj Şekillerinden Tayini için Basit, Duyarlı ve Güvenilir bir SK-FDD Yöntem(2012) Gümüştaş, Mehmet; Özkan, Sibel A.Gemifloksasin mesilat'ın (GEM) miktar tayini için duyarlı, doğru, hızlı, tamamen valide edilmiş, güvenilir ve basit bir foto diyot dizi (FDD) dedektörlü sıvı kromatografi (SK) yöntemi geliştirilmiştir. Bu yöntemde GEM ve iç standartın (IS) 272 nm deki tayini için bir ters faz RP-18 (X-Select, 250 x 4.6 mm ID x 5µ) kolonla birlikte 1.0 ml/dak akış hızında 15 mM fosforik asit içeren (pH 2.50) metanol-su (50:50; h/h) karışımı hareketli faz olarak kullanılmıştır. İç standart (IS) olarak Granisetron seçilmiştir. Bu koşullar kullanıldığında alıkonma süreleri IS için 3.20 ve GEM için 4.25 dakika bulunmuştur. Gerekli bütün validasyon parametreleri ve sistem uygunluk testi sonuçları detaylı olarak elde edilmiştir. Derişim aralığı 0.25-20 µg/mL arasında doğrusaldır. Gözlenebilme sınırı ve tayin alt sınırı değerleri sırasıyla 0.004 ve 0.013µg/mL olarak bulunmuştur. Yöntemin gün içi ve günler arası kesinlik çalışmaları sonucunda % Bağıl standart sapmaları (BSS) sırasıyla % 0.069 ve % 0.101'dir. Valide edilen yöntem farmasötik dozaj formlarına uygulanmış ve geri kazanım sonucu % 99.96 olarak bulunmuştur. Bu sonuçlar da göstermektedir ki önerilen yöntemin basit ve hızlı bir analize imkan verdiği için avantajlı olduğunu göstermektedir.Öğe Investigation of voltammetric behavior and electroanalytical determination of anticancer epirubicin via glassy carbon electrode using differential pulse and square wave voltammetry techniques(Editions de l'Academie Republique Populaire, 2015) Kurbanoğlu, Sevinç; Bozal Palabıyık, Burçin; Gümüştaş, Mehmet; Uslu, Bengi; Özkan, Sibel AyşılThe electrochemical oxidation of epirubicin was investigated using cyclic, differential pulse and square wave voltammetry at glassy carbon electrode. The aim of the study was to determine epirubicin levels in pharmaceuticals via electrochemical methods. The oxidation process was quasi-reversible over the pH range studied and exhibited diffusion controlled electrode process. All experimental parameters have been optimized under the optimum conditions. The oxidation peak current was linearly proportional to the concentration of epirubicin in the range of 2×10-7-3.6×10-5 M with a detection limit of 4.1×10-8 M and 4.9×10-8 M by differential pulse and square wave voltammetry, respectively. These unique properties make the sensor suitable for the analysis of the trace amounts of epirubicin in pharmaceutical preparations. The proposed methods were applied to commercial preparations. Differential pulse and square wave voltammetry techniques were compared with t-test and F-test.Öğe Modern Assay Techniques for Cancer Drugs: Electroanalytical and Liquid Chromatography Methods(Taylor and Francis Ltd., 2018) Kurbanoğlu, Sevinç; Karadaş Bakırhan, Nurgül; Gümüştaş, Mehmet; Özkan, Sibel AyşılIn the past decades, patients who have chemotherapy treatment have considerably increased number. At this point, the development of rapid precise, and reliable methods are very important to analyze cancer drugs from their dosage forms, animals or human biological samples. Among all the analytical methods, electrochemical methods hold an important position with their unique properties such as specificity in the biological recognition process, fast response, and their reliability and do not need a pretreatment process. Chromatographic methods are also used in a wide range of analytical applications for the analyses of anticancer drugs. The power of chromatography comes from its ability to separate a mixture of analytes and determination of their concentrations. Chromatographic techniques can mainly be divided into gas, liquid, and supercritical fluid chromatography. In the frame of this information, this review is aimed to provide basic principles of electroanalytical and high-performance liquid chromatography methods for the analysis of cancer drugs. In addition, some selected applications for electrochemistry-related techniques and high-performance liquid chromatography, for the determination of anti-cancer pharmaceuticals published in the last five years are also discussed. © 2018, © 2018 Taylor & Francis Group, LLC.Öğe Nanosized Drug Carriers for Oral Delivery of Anticancer Compounds and the Importance of the Chromatographic Techniques(Elsevier, 2017) Şengel Türk, Ceyda Tuba; Gümüştaş, Mehmet; Uslu, Bengi; Özkan, Sibel AyşılCancer is the primary leading cause of mortality in the world. The key of a successful cancer treatment depends on many important parameters, such as the application route, anticancer compound, and dosage form. Among the administration routes, oral application is the most widely used application method. However, oral administration of many molecules as conventional dosage forms is limited due to a major problem-low bioavailability. Nanoscale drug delivery systems can ensure oral administration and improve the oral bioavailability of the drugs. Determination of the chemotherapeutically active molecules from the developed nanoscale systems has an important role in the effectiveness of the nanoparticles. Chromatographic techniques, especially liquid chromatography, are very suitable and accurate ways to determine the content of a pharmaceutical ingredient and its stability in both in vitro and in vivo systems. This chapter describes the importance of lipid- and polymer-based nanoscale drug delivery technologies of the anticancer molecules and summarizes the effect and type of the nanostructures, characterization parameters, analysis parameters, such as column types and mobile phase compositions, and validation parameters. © 2017 Elsevier Inc. All rights reserved.Öğe Optimization of stability indicating LC method for the sensitive in vitro determination from solid lipid nanoparticles and ex vivo analysis from rat skin of etofenamate(Bentham Science Publishers B.V., 2017) Gümüştaş, Mehmet; Şengel Türk, Ceyda Tuba; Badıllı, Ulya; Amasya, Gülin; Özkan, Sibel Ayşıl; Tarımcı, NilüferIntroduction: Etofenamate (2-(2-hydroxyethoxy) ethyl 2-[[3-(trifluoromethyl)phenyl]amino] benzoate) (ETO) is a yellowish viscous liquid which is a nonsteroidal anti-inflammatory drug (NSAID) that has been applied topically for joint and muscular pain and soft tissue disorders. Solid lipid nanoparticles (SLNs) are colloidal drug delivery systems prepared by non-irritant and nontoxic lipids that attract great interest because of their unique features. Semisolid SLNs are novel approach for dermal application of SLNs. Aims: The aim of this study was to show the development, validation, and application of a simple, selective and reliable RP-LC method that was extensively validated for its specificity and stability-indicating properties from its forced hydrolytic, oxidative, photolytic and thermal degradation products. Materials and Methods: In addition, the proposed method presented to application of ETO from rat skin extract in according to the United States Pharmacopeia and International Council on Harmonization Guidelines. For this reason, XSelect HSS T3 XP (150 x 4.6 mm ID x 2.5µm) (Waters Corp. Milford, MA, USA) analytical column was chosen for the best resolution. Mobile phase consisted of 0.1% H3PO4 in bidistilled water (pH adjusted to 7.0 with 5M NaOH) and acetonitrile in the ratio of (40:60, v/v) with the flow rate of 1 mL.min-1. The volume of the sample solutions was injected at 10µL and the detector was set up at 285 nm. The analysis was carried out at a temperature of 45oC. Coclusion: The developed stability indicating method presented low limit of detection, low limit of quantitation and good resolution between any of interferences from both commercial formulation and developed SLN formulation from rat skin, with symmetric, pure and perfect peak homogeneity. High percentage of recovery results shows that the proposed method is free from the interferences of the commonly used excipients and additives in the formulations of the commercial product or semisolid SLN formulations and also biological derivatives. © 2017 Bentham Science Publishers.
