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Yayın Determination of the toxicity preferences of ocular drug delivery system by comparing two different toxicity bioassays(Mary Ann Liebert, 2023) Üner, Burcu; Durgun, Meltem Ezgi; Özdemir, Samet; Taş, Çetin; Üner, Melike; Özsoy, YıldızOcular drug delivery methods are highly favored for boosting bioavailability, patient compliance, and lower adverse effects and dose frequency. In addition to preventing adverse effects from the active ingredient, the parts of drug delivery systems must be nontoxic and nonallergic as well. Mitochondrial toxicity test (MTT) and Hen's egg chorioallantois membrane (HET-CAM) assay are the most often utilized tests based on this dilemma. The toxicity of loteprednol etabonate loaded solid lipid nanoparticles, lipid nanostructured carriers, and nanoemulsion were compared. Oleic acid, Precirol®ATO5, and Pluronic® F68 were used in the preparation. Their toxicities were evaluated by using two different toxicity tests (MTT and HET-CAM). The results suggest that there are no significant differences between the HET-CAM and MTT assays. It is noteworthy that the HET-CAM assay offers a more cost-effective and environmentally friendly alternative to the MTT assay, as it does not require cell culture and generates less toxic waste. This information may be useful to consider when selecting between the two assays.Yayın 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; Durgun, Meltem Ezgi; Çelebi, Ali Riza Cenk; Özsoy, YıldızBackground/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.Yayın Nanodelivery approaches of phytoactives for skin cancers: Current and future perspectives(Bentham Science Publishers, 2025) Algın Yapar, Evren; Özdemir, Merve Nur; Durgun, Meltem Ezgi; Akbal Dağıstan, Özlem; Cavalu, Simona; Özsoy, Yıldız; Kartal, MuratIn recent years, there has been an increase in skin cancers due to external factors, especially environmental factors, and studies on treatment alternatives have gained importance. Nanomaterials are common, from sunscreen formulas to formulations designed to treat skin cancers at various stages. Using bioactives has multiple effects in treating skin cancers, which provides many advantages. In this regard, many phytochemicals gain importance with their antioxidant, anti-proliferative, anti-inflammatory, antiangiogenic, and analgesic effects. Their delivery with nanocarriers is on the agenda for phytochemicals to gain the targeted stability, effectiveness, and toxicity/safety properties. This review presents types of skin cancers, phytochemicals effective in skin cancers, and their nanocarrier-loaded studies from an up-to-date perspective.Yayın Preparation and in vitro characterisation of nanofibers for enhancing the water solubility of poorly soluble drugs(İstanbul University Press, 2025) Karamürsel, Elif; Uzel, Egemen; Aydilek, Neriman; Durgun, Meltem Ezgi; Özsoy, YıldızBackground and Aims: As the drug discoveries of the modern century have led to a rapid increase in the number of new drug candidates with low water solubility, nanofiber drug delivery systems have become a promising technology to increase the water solubility of drugs with a high surface-to-volume ratio. In this study, we aimed to prepare a nanofiber of a molecule with low water solubility and investigate its changing solubility properties. Methods: Three nanofiber dosage forms containing olanzapine (OLZ) active substance were developed by the electrospinning method using polyvinyl alcohol (PVA) polymer. Drug loading efficiency, zeta potential determination, electrical conductivity, rheology, field emission scanning electron microscopy (FESEM), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) analyses were performed to evaluate the in vitro characterisation of the formulations. The solubility profile of the optimised formulations in pH 7.4 phosphate buffer was evaluated. The stability of optimised formulations was evaluated in terms of physical properties (colour, shape, weight, diameter, and thickness) and drug amount for 35 days. Results: It was determined that the electrospinning property of the nanofiber preparation solution increased with the addition of ethanol to the polymer solvent medium. The active substance distribution in the nanofiber layer was more homogeneous in the N78 and N79 coded formulations with high zeta potential values compared to N69. Contrary to the homogeneous distribution problem, the loading efficiency of the N69-coded formulation containing chloroform (~29%) was higher than that of N79 (~9.8%). A 24-h solubility study in pH 7.4 phosphate buffer of the N78-coded formulation, which has an active ingredient loading efficiency of ~80.4%, confirmed the increased solubility of OLZ in water in the nanofiber drug delivery system. Conclusion: Further studies are needed to convert these model formulations into final drug products.Yayın Vesicular drug delivery systems: Promising approaches in ocular drug delivery(MDPI, 2024) Batur, Eslim; Özdemir, Samet; Durgun, Meltem Ezgi; Özsoy, YıldızOcular drug delivery poses unique challenges due to the complex anatomical and physiological barriers of the eye. Conventional dosage forms often fail to achieve optimal therapeutic outcomes due to poor bioavailability, short retention time, and off-target effects. In recent years, vesicular drug delivery systems have emerged as promising solutions to address these challenges. Vesicular systems, such as liposome, niosome, ethosome, transfersome, and others (bilosome, transethosome, cubosome, proniosome, chitosome, terpesome, phytosome, discome, and spanlastics), offer several advantages for ocular drug delivery. These include improved drug bioavailability, prolonged retention time on the ocular surface, reduced systemic side effects, and protection of drugs from enzymatic degradation and dilution by tears. Moreover, vesicular formulations can be engineered for targeted delivery to specific ocular tissues or cells, enhancing therapeutic efficacy while minimizing off-target effects. They also enable the encapsulation of a wide range of drug molecules, including hydrophilic, hydrophobic, and macromolecular drugs, and the possibility of combination therapy by facilitating the co-delivery of multiple drugs. This review examines vesicular drug delivery systems, their advantages over conventional drug delivery systems, production techniques, and their applications in management of ocular diseases.
