Flor ilave edilmiş itriyum hidroksiapatitin mikroyapı, mikrosertlik ve biyouyumluluk özelliklerinin incelenmesi.

The aim of this study was to investigate the microstructure, microhardness and biocompatibility properties of nano hydroxyapatite (HA) doped with a constant yttrium (Y3+) and varying fluoride (F-) compositions. HA was synthesized via precipitation method and sintered at 1100C for 1 hour. Increased densities were achieved upon Y3+ doping while F- doping led to a decrease in densities. For structural analysis, XRD, SEM and FTIR spectroscopy examinations were performed. No secondary phases were observed in XRD studies upon doping. Lattice parameters decreased due to substitutions of ions. In SEM analysis, addition of doping ions was observed to result in smaller grains. In FTIR analysis, in addition to the characteristic bands of HA, novel bands indicating the substitution of F- ions were observed in F- ion doped samples. The highest microhardness value was obtained for the sample doped with 2.5%Y3+, 1%F-. Increased F- ion contents resulted in decreased microhardness values. For biocompatibility evaluation, in vitro tests were applied to the materials. MTT assay was performed for Saos-2 cell proliferation analysis. Y3+ and F- ion incorporation was found to improve cell proliferation on HA discs. Cells were found to attach and proliferate on disc surfaces in SEM analysis. ALP assay showed differentiation of cells on the discs can be improved by doping HA with an optimum amount of F- ion. Dissolution tests in DMEM revealed that structural stability of HA was improved with F- ion incorporation. The material exhibiting optimum structural, mechanical and biocompatibility properties was HA doped with 2.5%Y3+, 1%F-.M.S. - Master of Scienc

Mikrodeformasyon ile Yüzey Özellikleri Değiştirilen 316L Paslanmaz Çeliğin Sentetik Vücut Sıvısı ile Etkileşimi

Bu çalışmada ortopedik uygulamalarda yaygın olarak kullanılan bir biyomedikal alaşım olan 316L paslanmaz çelik yüzeyinde mikro sertlik ölçüm cihazı kullanılarak mikrodeformasyon alanları oluşturulmuş ve elde edilen farklı yüzey desenlerinin biyouyumluluğa etkisi sentetik vücut sıvısı içi statik daldırma deneyleri ile test edilmiştir. 7 ve 21 günlük daldırma periyotlarının ardından örnek yüzeyleri oksit ve kalsiyum-fosfatlı yapıların çökelmesi, sıvılar ise iyon salımı açısından incelendiğinde, her iki açıdan da oluşturulan farklı mikrodeformasyon desenlerinin kontrol numunesine kıyasla iyileştirme sağladığı saptanıştır. Oluşturulan desenler arasında ise iz boyutu büyük, izler arası mesafesi geniş olan paternin optimum özellikleri sağlayan yüzey olduğu gözlenmiştir. Yüzey pürüzlülüğü ve sıvı içi oksit ve kalsiyum-fosfatlı yapıların çökelmesi arasında bir doğru orantı tespit edilememiş, bu da yüzey enerjisini belirlemede mikrodeformasyonun mikroyapısal mekanizmalar üzerindeki etkisinin daha belirleyici olabileceğine dair ön bulgular ortaya koymuştur

Spectrophotometric Determination of Antidepressant Drug Duloxetine in Pharmaceutical Preparations using pi-Acceptors

In this study, two simple and accurate spectrophotometric methods were presented for the determination of duloxetine hydrochloride (DLX) in pharmaceutical preparations. The methods were based on the reaction of DLX as n-electron donor with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as pi-acceptors to give highly colored complex species. The colored products were quantitated spectrophotometrically at 477 and 841 for DDQ, TCNQ, respectively. All variables were studied in order to optimize the reaction conditions. Beer's law was obeyed in the concentration ranges 10.0-50.0 and 15-60 mu g mL(-1) for DDQ and TCNQ method, respectively. The proposed methods have been successfully applied to the pharmaceutical analysis without any interference from excipients. The suggested procedures could be used for the determination of DLX in pharmaceutical preparations being sensitive, simple and selective

Simultaneous determination of desloratadine and pseudoephedrine sulfate in tablets by high performance liquid chromatography and derivative spectrophotometry

Simple and accurate reversed phase liquid chromatographic and first derivative spectrophotometric methods have been developed for simultaneous determination of desloratadine and pseudoephedrine in combined dosage forms. The first method is based on the separation of both drugs by high performance liquid chromatography using a C18 column and 10 m m orthophosphoric acid: acetonitrile (77: 23). The drugs are eluted at 1.0 ml/min flow rate and detected at 262 nm. Ondansetron was used as internal standard. The calibration graphs of desloratadine and pseudoephedrine were linear in the range of 1.0-10.0 mu g/ml and 48-480 mu g/ml, respectively. The detection limits of the method were found to be 0.14 mu g/ml and 3.80 mu g/ml for desloratadine and pseudoephedrine, respectively. The derivative spectrophotometric method depends on measuring the first derivative amplitudes at 280 and 244 nm for desloratadine and pseudoephedrine, respectively. The calibration graphs were linear in the range of 2.5-15.0 mu g/ml for desloratadine and 120-720 mu/ml for pseudoephedrine. The detection limits were found at 0.38 mu g/ml and 21.45 mu g/ml for desloratadine and pseudoephedrine, respectively. The proposed methods were successfully applied to the determination of these drugs in commercially available tablets

Determination of Rosuvastatin at Picogram Level in Serum by Fluorimetric Derivatization with 9-Anthryldiazomethane using HPLC

For the first time, a carboxyl group derivatization assay has been developed and validated for the determination of the cholesterol-lowering drug rosuvastatin in human serum at picogram level by high-performance liquid chromatography with fluorescence detection. The assay procedure involved a simple one-step liquid liquid extraction of rosuvastatin with lovastatin as internal standard from serum with an ethyl acetate-methyl tertiary buthyl ether (1:1) mixture. After pre-column derivatization with 9-anthryldiazomethane at room temperature for one hour, the reaction mixture was injected onto a Phenomenex, Synergi C18 column (250 x 4.6 mm, 4 mu i.d.). The analytes were separated with a mobile phase composed of acetonitrile-water in gradient elution mode and detected at lambda(em) = 410 nm, exciting at 366 nm. Calibration curves were constructed in concentration range of 0.01-20.0 ng/mL and limit of detection and limit of quantification values were found to be 0.68 and 2.30 pg/mL, respectively. To test suitability of the developed methods for clinic use, the pharmacokinetics of rosuvastatin were investigated after oral administration of a 20 mg rosuvastatin film tablet to a healthy volunteer and maximum plasma concentration, time to reach that concentration and elimination half life were found to be 17.5 ng/mL, 3.5 h and 18.09 h, respectively