İstanbul Sağlık ve Teknoloji Üniversitesi Kurumsal Akademik Arşivi
DSpace@İSTÜN, Üniversite mensupları tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Impact of extraction solvents on total antioxidant capacity of barberry (berberis crataegina) plant
(Sivas Cumhuriyet University, 2025) Özdemir Olgun, Fatoş Ayça; Demirata Öztürk, Birsen
Defense mechanisms involving antioxidant molecules play a key role in neutralizing free radicals formed in the human body. It is important to determine the content of these molecules, which have become important in human nutrition in recent years, in consumed foods. This study aims to determine the total antioxidant capacity of the barberry (Berberis Crataegina) plant, which is consumed in many regions of Turkiye. For this purpose, firstly, barberry plant samples were collected from Mersin in summer season, the extracts were prepared with different solvents and CERAC method was used to determine the total antioxidant capacities of the samples. The highest value of total antioxidant capacity was obtained by 80 % (v/v) methanol solution for flesh part of the fruit. Total phenolic compound and total antioxidant capacities of the flesh part of barberry samples were calculated as 1.954 mmol gallic acid (GA) g-1 and 1.288 mmol Tr (TR) g-1, by Folin-Ciocalteu method and Cerium Reducing Antioxidant Capacity Assay (CERAC), respectively.
Seryum oksit nanopartküller: Sentez, karakterizasyon ve analitik kimya uygulamaları
(BİDGE Yayınları, 2025) Özdemir Olgun, Fatoş Ayça
Nanoteknoloji, nano boyutta mühendisliği ve teknolojiyi kapsayan endüstri, elektronik ve sağlık alanında birçok uygulaması olan bir bilim dalıdır. Nanopartiküller 1-100 nm boyutlarına sahip nano boyutlu malzemeleri kapsamaktadır (Khan Ibrahim et al., 2017). Nanopartiküllerin nano ölçekli olmasıyla yığın malzemelerden farklı fiziksel ve kimyasal özelliklere sahiptir. Yığın malzemelerden daha iyi özellik göstermesiyle pek çok alanda nanopartiküller yenilikler sunarak malzemelerin özellikleri iyileştirmek ve daha verimli hale getirmek için sıklıkla kullanılırlar. Bu alandaki araştırmalar nanopartiküllerin fiziksel ve kimyasal özelliklerini inceleyerek çeşitli uygulama alanlarındaki rollerini anlamayı hedeflemektedir. Seryum oksit nanopartikülleri bu bakımdan önemli bir tür olup çeşitli endüstriyel ve çevre uygulamalarında kullanım alanları geliştirilen bir malzemedir (Altammar, 2023).
Application of liquid-liquid microextraction techniques for trace level determination of organic/inorganic analytes in biological, medical, environmental and forensic samples
(Elsevier, 2025) Chormey, Dotse Selali; Bodur, Sezin Erarpat; Öztürk Er, Elif; Zaman, Buse Tuğba; Bodur, Süleyman; Şaylan, Meltem; Dalgıç Bozyiğit, Gamze; Serbest, Hakan; Bakırdere, Sezgin
The drawbacks of the conventional liquid-liquid extraction method have been greatly alleviated with the advent of liquid-liquid microextraction methods, which are being actively utilized as effective sample preparation tools for biological, medical, environmental and forensic samples. The complex nature of these sample matrices tend to hinder the accuracy and precision of analytical measurements, and have the potential to cause false positive and false negative results. With sample preparation remaining an integral part of accurate determination of organic and inorganic analytes in complex samples, liquid-liquid microextraction as an efficient sample preparation approach facilitates the acquisition of analytes in final forms that are suitable for modern and classical analytical instruments. The use of very low solvent volumes in liquid-liquid microextraction methods leads to very high enrichment factors, and the availability of different extractants paves way for selective analyte extractions. Recent calls for greener approaches of analysis have been met with the introduction of several green solvents that boost the greenness of liquid-liquid microextraction methods and equally maintain the superiority of the methods. © 2024 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Formulation and characterization of an oleuropein-enriched oral spray gel: Microbiological performance and in ovo histopathological safety
(MDPI Publishing, 2026) Alparslan, Levent; Özdemir, Samet; Karacan, Burak; Tutar, Ömer Faruk; Doğan, Tunay; Akar, Remzi Okan; Yıldırım, Elifnur Gizem; Erdoğan, Nusret
Background/Objectives: Oleuropein is a bioactive phenolic compound from olive leaves with antimicrobial and antioxidant activity. This study aimed to develop a sprayable oral gel containing an oleuropein-rich aqueous extract and to evaluate its pharmaceutical performance antimicrobial efficacy and in ovo biological response. Methods: Oleuropein content was quantified using a validated chromatographic method. Polymeric systems were screened to select an optimized sprayable formulation. Physicochemical stability, dose uni formity, and antimicrobial activity against major cariogenic bacteria were evaluated. In ovo biological evaluation was conducted using the chick chorioallantoic membrane angiogene sis model together with histopathological examination of embryonic heart and liver tissues. Results: Oleuropein content was determined as 288.6 µg/mL in the olive leaf extract and 255.1 µg/mL in the final formulation. The optimized oral spray showed stable physico chemical properties, with pH maintained at 6.90 ± 0.02 and no relevant changes in viscosity during storage. The mean delivered dose per actuation was 0.128 ± 0.015 g, corresponding to 32.6 µg oleuropein per spray. The formulation exhibited inhibitory activity against all tested cariogenic microorganisms, with MIC values ranging from 13.3 to 170.7 µg/mL and MBC values generally two-fold higher. In the CAM assay, significant concentration- and time-dependent antiangiogenic effects were observed after 24–48 h at moderate and higher concentrations. Histopathological evaluation revealed dose-dependent acute degenerative and congestive changes in heart and liver tissues without evidence of fibrosis or steatosis. Conclusions: The oleuropein-based sprayable oral gel is a promising localized delivery system with adequate stability dose uniformity and antimicrobial efficacy. In ovo findings provide a conservative assessment of systemic exposure and support further development for oral biofilm and caries-related applications.
Development of brimonidine-loaded ethosomes for glaucoma: Investigation of intraocular pressure-lowering potential in vivo
(MDPI Publishing, 2026) Özdemir, Samet; Sağıroğlu, Ali Asram; Şen, Eslim; Gelmez Yıldız, Büşra; Karimli, Laman; Ezgi Durgun, Meltem; Çelebi, Ali Riza Cenk; Özsoy, Yıldız
Background/Objectives: Brimonidine tartrate (BRT), a selective α2-adrenergic receptor agonist, is commonly used in the treatment of glaucoma. However, conventional eye drop formulations suffer from poor ocular bioavailability and rapid elimination. This study aimed to develop and evaluate BRT-loaded ethosomes as a nanocarrier-based alternative to enhance intraocular delivery and therapeutic efficacy. Methods: Ethosomes were prepared using the thin-film hydration method and optimized via central composite design. The optimized formulation was subjected to physicochemical characterization, in vitro release testing, and ocular irritation assessment using the Hen egg test—chorioallantoic membrane (HET-CAM) model. Additionally, the intraocular pressure (IOP)-lowering efficacy of the formulation was evaluated in a rat glaucoma model. Results: The optimized ethosomal formulation exhibited favorable physicochemical properties, including a mean particle size of 122.6 ± 0.7 nm, zeta potential of −1.8 ± 0.9 mV, and encapsulation efficiency of 87.33 ± 0.04%. In vitro release data followed Higuchi kinetics. HET-CAM analysis indicated non-irritancy. In vivo, the ethosomal BRT formulation achieved comparable IOP-lowering effects to the marketed eye drops at one-third of the dose. Conclusions: The developed BRT loaded ethosomal system demonstrated promising physicochemical stability, sustained release, and therapeutic potential. These findings suggest that ethosomes may offer a safe and effective strategy for enhancing the ocular delivery of BRT in glaucoma therapy.
