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Öğe Application of HPLC to Investigate the Physicochemical Properties and Intestinal Permeability of Ketoprofen(Bentham Science Publ Ltd, 2017) Kaynak, Mustafa Sinan; Celebier, Mustafa; Akgeyik, Emrah; Sahin, Selma; Altinoz, SacideThe main objective of this study was to investigate the effect of pH on the solubility and intestinal permeability of ketoprofen by using HPLC. Ketoprofen is a slightly soluble acidic drug, and its solubility in aqueous phase is affected by pH changes dramatically. However, there is no data in the literature to support whether this pH dependent water solubility of ketoprofen will influence its absorption/bioavailability. In this study, the distribution-coefficient (log D) of ketoprofen at various pH values between 4.5 and 7.5 were investigated using HPLC, and then it was made an attempt to correlate the log D values with the intestinal permeability values. For this reason, in vivo intestinal permeability studies were performed at pH 4.5 and pH 7.5. The concentrations of model and reference compounds and also the blank buffers passed though the rat intestine were analyzed by means of a validated HPLC method. A nonlinear relationship was found between the results of in vitro and in vivo studies indicating that the diffusion of ketoprofen was not only related with passive diffusion, but also could be related with active transport.Öğe ASSESSMENT OF PHARMACEUTICAL QUALITY AND RELEASE KINETICS OF METOPROLOL TARTRATE EXTENDED RELEASE TABLETS AVAILABLE IN TURKISH DRUG MARKET(2020) Gencer, Ayşe; Akgeyik, Emrah; Kaynak, Mustafa Sinan; Çelebier, Mustafa; Berkman, Murat Sami; Şahin, SelmaAbstract: Cardioselective ?-adrenergic blocker metoprolol tartrate, is used in the treatment of different diseases such as cardiac arrhythmias, hypertension, heart failure, angina pectoris, migraine, and hyperthyroidism. Beside dosage forms of the parenteral ampoule and conventional tablets of different manufacturers, there are extended release tablets of metoprolol tartrate in the Turkish Drug Market. In this research work, comparative quality control studies of metoprolol tartrate extended release tablets (original and generic) produced by two different pharmaceutical companies in the Turkey were carried out and evaluated according to the related guidelines. Thickness and diameter, hardness, weight variation, friability, content uniformity and dissolution rate were examined as quality control parameters. A new validated HPLC method for the quantification of metoprolol tartrate has been developed. An ACE column (C18, 5 µm, 250x4.6 mm) and acetonitrile: phosphate buffer (30: 70, v/v) mobile phase were used for the determination of metoprolol tartrate. The tablets showed extended release for 8 hours (70.74% release from drug A, 76.87% from the drug B). Both products have acceptable hardness, friability and weight variation values. Content of the active ingredient of the tablets was consistent with label claim (99.45% for drug A and 96.45% for drug B). The dissolution data were evaluated by model dependent and model independent methods using DDSolver program. The obtained results showed that release kinetics of both drugs were well fitted with the Korsmeyer-Peppas model.Öğe Comparison of Dissolution Profiles of Commercially Available Lamivudine Tablets(Dissolution Technologies, Inc, 2015) Ozturk, Naile; Kaynak, Mustafa Sinan; Sahin, SelmaThe aim of this study was to investigate the influence of dissolution medium on the in vitro release of lamivudine (100 mg) from four commercially available lamivudine tablets (one reference and three generic). Three different buffer solutions (pH 1.2, 4.5, 6.8) and deaerated water were used as the dissolution media (900 mL), and the paddle rotation speed was kept at 50 rpm with twelve replicates. An RP HPLC method was developed for analysis of lamivudine in samples obtained from dissolution studies. The mobile phase consisted of acetonitrile/water (10:90) pH adjusted to pH 2.5 with o-phosphoric acid, a C-18 column (Ace 250 x 4.60 mm, 5 mu m) was used, and the flow rate was set at 1 mL/min. All the drugs tested were very rapidly dissolving (more than 85% of the labeled amount in 15 min), and the dissolution profiles of the generic tablets were thus considered similar to that of the reference tablet in each of the buffers at pH 1.2, 4.5, and 6.8, and deaerated water. Because of the dissolution results and the high solubility and borderline permeability, a biowaiver can be proposed for lamivudine immediate-release solid oral dosage forms provided that the excipient composition of the test product is the same as or similar to that of the reference product and the excipients that have an effect on bioavailability are qualitatively and quantitatively the same as that of the reference product.Öğe Comparison of intestinal permeability of nebivolol hydrochloride loaded solid lipid nanoparticles with commercial nebivolol tablet(2018) Üstündağ-Okur, Neslihan; Yurdasiper, Aysu; Kaynak, Mustafa Sinan; Gökçe, Evren HomanAbstract: The oral application of drugs is the most popular route for achieving systemic effects, nevertheless, it is limited by difficulties related to physicochemical properties of the drug. Solid lipid nanoparticles (SLNs) are appealing extensive notice because of showing increased solubility and improved oral bioavailability via different mechanisms. The aim of the study is to compare and peruse the in-situ permeation of nebivolol (NBV) loaded SLN and its commercial tablet formulation used for the treatment of hypertension. For this aim Single-Pass Intestinal Perfusion (SPIP) method was used for in-situ permeation studies. NBV loaded SLNs were prepared and modified with polyethylene glycol (PEG). In order to prepare SLNs by homogenization technique, compritol, lecithin and poloxamer were chosen. Particle sizes of blank and loaded SLN were 213.4±17.5 and 264.1±18.8 nm, respectively with polydispersity index values of approximately 0.3 for each. NBV loading resulted in positive electrical charge on SLNs. The encapsulation efficiency was 98.04±0.2 %. Permeability coefficient values were tripled when NBV was incorporated in SLNs and doubled when pure NBV was given separately with a blank SLN. PEG modified SLN can be used to enhance oral absorption of NBV, and SLNs alone can be used as permeation enhancer in oral drug delivery..Öğe Demographics and clinical characteristic of patients diagnosed with hen’s egg allergy(2019) Topal, Erdem; Arga, Mustafa; Celiksoy, Mehmet Halil; Kaynak, Mustafa Sinan; Duman, Yücel; Demirtas, Semih; Alatas, Cem; Tonbul, Hayrettin; Dalkilic, Huri MaralAim: To assess the demographics, clinical characteristics and natural course of patients diagnosed with hen’s egg allergy.Material and Methods: Patients who were diagnosed with hen’s egg allergy were included in this study. The patients’ medical records were analyzed to collect demographic and clinical data.Result: 88 patients diagnosed with hen’s egg allergy were included in the study. 46 (52.3%) of the patients were male, their median age was 33 months and their median follow-up period was 18 months. 44 (50%) of the patients had comorbid atopic disease. 49 (55.7%) of the children’s parents had a diagnosis of atopic disease, while 5 (5.7 %) had a diagnosis of food allergy. In terms of the patients’ clinical symptoms, 86 (97.7%) had cutaneous symptoms, 16 (18.2%) had gastrointestinal system symptoms, 13 (14.8%) had respiratory system symptoms. In the follow-up, 43 (48.9%) of the patients were found to develop tolerance. When the patients allergic to egg white and those allergic to egg yolk were compared in terms of clinical findings, atopic eczema exacerbation was found to be more frequent (p=0.012) in patients allergic to egg white; while urticaria (p=0.005) and cough (p=0.012) were found to be more frequent in patients allergic to egg yolk.Conclusion: In clinical presentations that develop as a result of egg allergy, the most frequent symptoms are dermatological, gastrointestinal system and respiratory system symptoms, respectively. However, while atopic eczema exacerbations are more frequent in patients allergic to egg white, symptoms related with respiratory tract are more common in patients allergic to egg yolk. Keywords: Allergy; Cow’s Milk; Persistence; Predictive Factors; Tolerance.Öğe Demographics and clinical characteristic of patients diagnosed with hen’s egg allergy(2019) Topal, Erdem; Arga, Mustafa; Çeliksoy, Mehmet Halil; Kaynak, Mustafa Sinan; Duman, Yücel; Demirtaş, Hasan; Alataş, Cem; Tonbul, Hayrettin; Maral Dalkılıc, HuriAbstract: Aim: To assess the demographics, clinical characteristics and natural course of patients diagnosed with hen’s egg allergy. Material and Methods: Patients who were diagnosed with hen’s egg allergy were included in this study. The patients’ medical records were analyzed to collect demographic and clinical data. Result: 88 patients diagnosed with hen’s egg allergy were included in the study. 46 (52.3%) of the patients were male, their median age was 33 months and their median follow-up period was 18 months. 44 (50%) of the patients had comorbid atopic disease. 49 (55.7%) of the children’s parents had a diagnosis of atopic disease, while 5 (5.7 %) had a diagnosis of food allergy. In terms of the patients’ clinical symptoms, 86 (97.7%) had cutaneous symptoms, 16 (18.2%) had gastrointestinal system symptoms, 13 (14.8%) had respiratory system symptoms. In the follow-up, 43 (48.9%) of the patients were found to develop tolerance. When the patients allergic to egg white and those allergic to egg yolk were compared in terms of clinical findings, atopic eczema exacerbation was found to be more frequent (p=0.012) in patients allergic to egg white; while urticaria (p=0.005) and cough (p=0.012) were found to be more frequent in patients allergic to egg yolk. Conclusion: In clinical presentations that develop as a result of egg allergy, the most frequent symptoms are dermatological, gastrointestinal system and respiratory system symptoms, respectively. However, while atopic eczema exacerbations are more frequent in patients allergic to egg white, symptoms related with respiratory tract are more common in patients allergic to egg yolk.Öğe Determination of in vitro Dissolution Profiles of Amlodipine Besylate and Olmesartan Medoxomil Using a New HPLC Method(Chiminform Data S A, 2013) Kaynak, Mustafa Sinan; Celebier, Mustafa; Sahin, Selma; Altinoz, SpodeThe aim of this study was to develop an HPLC method for simultaneous determination of these active compounds and to apply this method to determine the dissolution of AML and OLM from a commercially available tablet. Valsartan (VAL) was used as an internal standard (IS). Separation of AML, OLM and VAL was performed using Phenomenex C-18 column (Luna 5 mu, 100A, 250x4.6 mm; California, USA) protected with a Phenomenex C-18 guard column (4.0x3.0 mm; California, USA). The chromatographic separation operated isocratically at room temperature using a mobile phase consisted of phosphate buffer (pH 4.0, 0.04 mol/L):methanol:acetonitrile (40:45:15, v/v/v) delivered at a flow rate of 0.8 mL/min and injection volume was 10 mu L. The diode array detector was set at 234 nm and 205 nm wavelengths for the quantification of AML and OLM respectively. In vitro dissolution studies revealed that 85% of the labeled amounts of AML and OLM were released within 25 min from their fixed combination tablet dosage form. The developed HPLC method was validated according to the ICH guidelines and it is proposed for dissolution studies of the combination dosage forms of these compounds.Öğe Determination of Regional Intestinal Permeability of Diclofenac and Metoprolol Using a Newly-Developed and Validated High Performance Liquid Chromatographic Method(Pharmacotherapy Group, 2015) Kaynak, Mustafa Sinan; Buyuktuncel, Ebru; Caglar, Hatice; Sahin, SelmaPurpose: To develop a simple and rapid reversed-phase high performance liquid chromatographic (HPLC) method with UV detection for the simultaneous determination of diclofenac, metoprolol tartrate, phenol red and propyl paraben in intestinal segments. Methods: The mobile phase consisted of 55% methanol, 45% of 12.5 mM potassium dihydrogen phosphate (KH2PO4) aqueous solution, adjusted to pH 7.0 using 0.2 N sodium hydroxide (NaOH) solution, and to which 0.3% (v/v) triethylamine was added. Analysis was run at a flow rate of 1.0 mL/min with a 12 min total run time at ambient temperature. The developed method was successfully applied to determination of the analytes in samples obtained from in situ single pass intestinal perfusion (SPIP) studies. Results: The calibration curves were linear for all compounds (r > 0.999) with a limit of detection (LOD) of 0.005, 0.1, 0.075 mu g/mL, and limit of quantification of 0.1, 0.3, 0.2 mu g/mL for metoprolol tartrate, phenol red and diclofenac respectively. The coefficient of variation for intra-day and inter-day precision was < 5% and accuracy was between 98 and 102%. Based on SPIP and HPLC studies, the estimated mean permeability in jejunum, ileum and colon was 0.319 +/- 0.184, 0.639 +/- 0.241 and 0.84 3 +/- 0.517 x 10(-4) cm/sec, respectively, for metoprolol tartrate while the corresponding permeability values were 1.585 +/- 0.729, 1.154 +/- 0.433 and 1.775 +/- 1.576 x 10(-4) cm/sec for diclofenac. Conclusion: The findings indicate that diclofenac is a highly permeable compound and its absorption occurs throughout the intestinal tract. Furthermore, the developed method is suitable for the analysis of diclofenac and metoprolol in intestinal regions.Öğe Determination of the Physicochemical Properties of Piroxicam(Turkish Pharmacists Assoc, 2020) Celebier, Mustafa; Nenni, Merve; Kaplan, Ozan; Akgeyik, Emrah; Kaynak, Mustafa Sinan; Sahin, SelmaObjectives: The aim of this study was to determine the acid dissociation constant (pKa) of piroxicam using high performance liquid chromatography (HPLC) and ultraviolet-visible (UV-Vis) spectrophotometry, and to determine the partition coefficient (Log P), distribution coefficient (Log D), and Log kw values of piroxicam using HPLC. Materials and Methods: The HPLC studies were performed on a reversed-phase ACE C18 (150x4.6 mm ID, 5 mu m) column at a flow rate of 1.0 mL min-1. The detector was set to 360 nm. Log D at different pH values (3.0-6.5) was examined with a phosphate buffer (20 mM) and acetonitrile (30:70 v/v) mixture as the mobile phase. For pKa determination, HPLC studies were performed with a mixture of phosphate buffer (20 mM) and methanol within the pH range of 3.50-6.00. Log kw measurements were performed with phosphate buffer (20 mM) and MeOH (from 20:80 v/v to 10:90 v/v) mixtures within the pH range of 3.50-6.00. UV-Vis spectrophotometric pKa measurements were performed at 285 nm wavelength. Results: The pKa value of piroxicam was found to be 5.3 by HPLC and 5.7 by UV-Vis spectrophotometry. Log P of piroxicam was determined as 1.58 in our experimental conditions. Log D values were 1.57, 1.57, 1.44, 1.13, and 0.46 for pH values of 3.17, 3.79, 4.44, 5.42, and 6.56, respectively. Conclusion: In the literature, different Log P (3.1, 2.2, and 0.6) and pKa (6.3 and 4.8) values were reported for piroxicam. The Log P (1.58) and pKa (5.3 and 5.7) values obtained for piroxicam in our study were within the range of the literature values. All these results indicate that different experimental approaches used for the determination of physicochemical properties could provide different values. Although UV spectrophotometry is easy to apply, HPLC is a unique technique for simultaneous determination of pKa, Log D, and Log P values of compounds.Öğe Development of HPLC Methods for Individual Determination of 20 Active Pharmaceutical Ingredients for Ussing-Chamber Studies(Bentham Science Publ Ltd, 2017) Kaynak, Mustafa Sinan; Akgeyik, Emrah; Ates, Muge; Celebier, Mustafa; Sahin, SelmaBackground: The aim of this study was to develop HPLC methods for individual determination of 20 active pharmaceutical ingredients (amoxicillin sodium, antipyrine, atenolol, caffeine, carbamazepine, cimetidine, enalapril, furosemide, hydrochlorothiazide, ibuprofen, ketoprofen, metoprolol tartrate, methyldopa, naproxen sodium, pindolol, piroxicam, propranolol HCl, ranitidine, theophylline, and verapamil HCl) to be used for determination of their intestinal permeabilities across Ussing-Chamber. Method: Two different stationary phases (Waters X-Bridge C18-150 x 4.6 mm, 5 mu m; and ACE 5 C18- 150 x 4.6 mm, 5 mu m) were used for the separation of the compounds. Three different aqueous phases (20 mM phosphate buffers pH 3.0, pH 6.0 and water) and two different organic phases (methanol and acetonitrile) were used to prepare the mobile phases. Total analysis time was shorter than 7 minutes for all applications. Result: The developed methods were validated according to the ICII guideline and found to be linear, sensitive, selective, precise and accurate. The developed methods could be applied for analyses of these compounds not only for Ussing-Chamber studies but also for other permeability studies.Öğe Effect of permeability enhancers on paracellular permeability of acyclovir(Wiley, 2016) Ates, Muge; Kaynak, Mustafa Sinan; Sahin, SelmaObjectives According to Biopharmaceutics Classification System (BCS), acyclovir is a class III (high solubility, low permeability) compound, and it is transported through paracellular route by passive diffusion. The aim of this study was to investigate the effect of various pharmaceutical excipients on the intestinal permeability of acyclovir. Methods The single-pass in-situ intestinal perfusion (SPIP) method was used to estimate the permeability values of acyclovir and metoprolol across different intestinal segments (jejunum, ileum and colon). Permeability coefficient (P-eff) of acyclovir was determined in the absence and presence of a permeation enhancer such as dimethyl beta-cyclodextrin (DM-beta-CD), sodium lauryl sulfate (SLS), sodium caprate (Cap-Na) and chitosan chloride. Key findings All enhancers increased the permeability of paracellularly transported acyclovir. Although Cap-Na has the highest permeability-enhancing effect in all segments, permeation-enhancing effect of chitosan and SLS was only significant in ileum. On the other hand, DM-beta-CD slightly decreased the permeability in all intestinal segments. Conclusions These findings have potential implication concerning the enhancement of absorption of paracellularly transported compounds with limited oral bioavailability. In the case of acyclovir, Cap-Na either alone or in combination with SLS or chitosan has the potential to improve its absorption and bioavailability and has yet to be explored.Öğe Evaluation of Pharmaceutical Quality of Conventional Dosage Forms Containing Paracetamol and Caffeine Available in the Turkish Drug Market(Dissolution Technologies, Inc, 2016) Akgeyik, Emrah; Kaynak, Mustafa Sinan; Celebier, Mustafa; Altinoz, Sacide; Sahin, SelmaThe aim of this study was to evaluate the quality of conventional paracetamol- (PA) and caffeine- (CA) containing combined dosage forms in the Turkish drug market. For this purpose, weight variation, content uniformity, diameter and thickness, hardness, friability, disintegration, and dissolution tests were carried out. Content uniformity and dissolution tests were performed by a validated high-performance liquid chromatography (HPLC) method. Separations were carried on an ACE 5-C-18, 5-mu m LC column (250 x 4.6 mm) using isocratic elution with a methanol/water (40:60 v/v) mobile phase. The injection volume was 20 mu L, and UV detection was performed at 270 nm. The weight variation results were in accordance with content uniformity results. All dosage forms fulfilled the USP requirement of not less than 75% of active ingredients of the labeled claim dissolved within 60 min. Also, all tablets met the rapidly dissolving criterion (more than 85% of the labeled amount of the drug substance dissolved within 30 min). The results of this study indicate that PA- and CA-containing conventional dosage forms available in the Turkish drug market pass all the established quality control tests successfully, and they can be used interchangeably.Öğe HPLC METHOD DEVELOPMENT AND VALIDATION: SIMULTANEOUS DETERMINATION OF DICLOFENAC, METOPROLOL AND PHENOL RED IN BIOLOGICAL MATRIX FOR INTESTINAL PERFUSION STUDIES(Elsevier Science Bv, 2009) Caglar, Hatice; Kaynak, Mustafa Sinan; Sahin, Selma; Buyuktuncel, Ebru[Abstract Not Available]Öğe HPLC method development for the simultaneous analysis of amlodipine and valsartan in combined dosage forms and in vitro dissolution studies(Univ Sao Paulo, Conjunto Quimicas, 2010) Celebier, Mustafa; Kaynak, Mustafa Sinan; Altinoz, Sacide; Sahin, SelmaA simple, rapid and reproducible HPLC method was developed for the simultaneous determination of amlodipine and valsartan in their combined dosage forms, and for drug dissolution studies. A C 18 column (ODS 2, 10 mu m, 200 x 4.6 mm) and a mobile phase of phosphate buffer (pH 3.6, 0.01 mol L-1): acetonitrile: methanol (46: 44: 10 v/v/v) mixture were used for separation and quantification. Analyses were run at a flow-rate of 1 mL min(-1) and at ambient temperature. The injection volume was 20 mu L and the ultraviolet detector was set at 240 nm. Under these conditions, amlodipine and valsartan were eluted at 7.1 min and 3.4 min, respectively. Total run time was shorter than 9 min. The developed method was validated according to the literature and found to be linear within the range 0.1 -50 mu g mL(-1) for amlodipine, and 0.05 - 50 mu g mL(-1) for valsartan. The developed method was applied successfully for quality control assay of amlodipine and valsartan in their combination drug product and in vitro dissolution studies.Öğe Independent predictive factors for the persistence and tolerance of cow's milk allergy(Wiley, 2019) Topal, Erdem; Celiksoy, Mehmet Halil; Arga, Mustafa; Kaynak, Mustafa Sinan; Duman, Yucel; Demirtas, Semih; Alatas, CemBackground Cow's milk protein allergy (CMPA) is usually transient, with most children tolerating ingested cow's milk by 3 years of age. This study aimed to determine factors that promote or hindering the development of tolerance to CMPA. Methods A logistic regression model was used to determine independent risk factors associated with tolerance and persistence of CMPA. Result A total of 178 children diagnosed with CMPA were included in the study. The patients' median age was 32 months (minimum-maximum, 14 to 144 months), and their median follow-up period was 30 months (minimum-maximum, 12 to 54 months). In the follow-up, CMPA persisted in 62 (34.8%) patients. The patients were divided into 2 groups according to patient's age. Group I was <3 years old and group II was >= 3 years old. The factors independently associated with the persistence of CMPA for group I were as follows: comorbid food allergies (p = 0.021), the presence of an immunoglobulin E (IgE)-mediated reaction (p = 0.001), and respiratory system symptoms (ie, tachypnea) (p = 0.036). The presence of gastrointestinal-related discomfort (p = 0.001) was an independent risk factor associated with the development of tolerance. The presence of comorbid food allergies (p = 0.03) was the only independent predictive factor for CMPA persistence for group II. Conclusion The prognosis in cases of CMPA, a food allergy, is good, with tolerance developing over time. The presence of IgE-mediated CMPA, respiratory-related symptoms (ie, tachypnea), and the presence of comorbid food allergies have negative effects on tolerance.Öğe Ussing-Chamber Tekniği Kullanılarak İlaçların Biyoyararlanımlarının Tayin Edilmesi(2016) Ateş, Müge; Kaynak, Mustafa Sinan; Şahin, Selma[Abstract Not Available]Öğe UV Spectrophotometric Method for Determination of the Dissolution Profile of Rivaroxaban(Dissolution Technologies, Inc, 2014) Celebier, Mustafa; Kaynak, Mustafa Sinan; Altinoz, Sacide; Sahin, SelmaRivaroxaban is an oral anticoagulant that is the first available orally active direct Factor Xa inhibitor. In this study, a UV spectrophotometric method was developed for the determination of rivaroxaban content in pharmaceutical formulations and the amount of rivaroxaban released in tablet dissolution studies. The dissolution profile of rivaroxaban was successfully determined with the validated method.
