Yazar "Altinoz, Sacide" seçeneğine göre listele

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    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, Sacide
    The 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.
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    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, Selma
    The 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.
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    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, Selma
    A 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.
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    UV Spectrophotometric Method for Determination of the Dissolution Profile of Rivaroxaban
    (Dissolution Technologies, Inc, 2014) Celebier, Mustafa; Kaynak, Mustafa Sinan; Altinoz, Sacide; Sahin, Selma
    Rivaroxaban 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.