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    Applications of chitosan in prevention and treatment strategies of infectious diseases
    (2024) Sinani, Genada; Sessevmez, Melike; Şenel, Sevda
    Chitosan is the most commonly investigated functional cationic biopolymer in a wide range of medical applications due to its promising properties such as biocompatibility, biodegradability, and bioadhesivity, as well as its numerous bioactive properties. Within the last three decades, chitosan and its derivatives have been investigated as biomaterials for drug and vaccine delivery systems, besides for their bioactive properties. Due to the functional groups in its structure, it is possible to tailor the delivery systems with desired properties. There has been a great interest in the application of chitosan-based systems also for the prevention and treatment of infectious diseases, specifically due to their antimicrobial, antiviral, and immunostimulatory effects. In this review, recent applications of chitosan in the prevention and treatment of infectious diseases are reviewed, and possibilities and limitations with regards to technical and regulatory aspects are discussed. Finally, the future perspectives on utilization of chitosan as a biomaterial are discussed.
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    Biodegradable polysaccharide aerogels based on tragacanth and alginate as novel drug delivery systems
    (2024) Al-barudi, Amenah; Sinani, Genada; Ülker, Zeynep
    Tragacanth, an anionic polysaccharide, is a natural material widely investigated for the synthesis of aerogels as drug delivery vehicles. Its biocompatibility, biodegradability, and affordability are all key features for its use in pharmaceutical applications. In this study, tragacanth and tragacanth alginate composite aerogels were prepared using the sol-gel technique followed by supercritical drying. Paracetamol was selected as a model drug for drug loading and release studies owing to its high solubility in ethanol and low solubility in supercritical carbon dioxide. The paracetamol loading into the aerogel pores was confirmed by infrared spectroscopy (IR) and x-ray diffraction (XRD) spectra of the resulting samples. Scanning electron microscopy (SEM) images showed that all aerogels were porous with a macroporous-mesoporous network. Due to the high porosity of the prepared aerogels, a loading of 99 wt% (mg drug/mg aerogel) for tragacanth and 114 wt% (mg drug/mg aerogel) for composite aerogels was achieved. Moreover, the release rate of the drug could be modified by manipulating the aerogel composition. Tragacanth aerogels had a faster release rate, while the addition of alginate prolonged the release rate of the model drug. Various empirical release models were investigated and the release rate was found to follow the Korsmeyer-Peppas (Power Law) model suggesting a diffusion-based release kinetics. Based on the results, the feasibility of utilizing tragacanth for the preparation of drug-loaded aerogels was shown. Tragacanth is a suitable polysaccharide for the synthesis of aerogels.Macropores/mesopores of all synthesized aerogels are suitable for drug loading.The presence of alginate retards the release of the model drug up to 20% at each time point.The release kinetics of the synthesized aerogels follow the Korsmeyer-Peppas model.
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    Current state of lipid nanoparticles (SLN and NLC) for skin applications
    (2023) Eroğlu, Cemre; Sinani, Genada; Ülker, Zeynep
    The increasing knowledge on skin physiology, formulation science and nanotechnology has led to continuous improvements in cosmetics, and introduction of dermocosmetics has been increasing particularly for the management of skin disorders such as acne, eczema, psoriasis, etc. Nowadays, research has been focused on the development of products which can efficiently administer active compounds to the target skin layers while minimizing side effects. The use of multifunctional lipid nanoparticles for cosmetic and dermocosmetic purposes is promising not only because biocompatible ingredients are used in their composition, but also because of their ability to show enhanced skin penetration. Although the introduction of liposomes has been a hallmark of lipid nanoparticles, development of novel systems capable of encapsulating active compounds with tunable release profiles, that show good stability, are easy to manufacture and handle remains a necessity. Solid lipid nanoparticles (SLN) were introduced as alternative formulations for emulsions, liposomes and polymeric nanoparticles, whereas nanostructured lipid carriers (NLC) were developed later as second-generation nanoparticles. However, both SLN and NLC show many inherited advantageous properties to be used for dermal applications including ability to provide occlusion and photoprotective effect and skin hydration, and various SLN and NLC based products are already in the market. This review provides an overview on the current state-of-art of SLN and NLC particularly for cosmetic and dermocosmetic purposes, discuss their formulation composition, structures and preparation techniques. Their use for the topical delivery of active compounds in different skin disorders is highlighted along with examples of commercialized products.
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    Formulation, optimization and in vitro evaluation of polymer-coated liposomes encapsulating nebivolol hydrochloride
    (2023) Sessevmez, Melike; Sinani, Genada; Çevikelli, Tilbe
    Hypertension, also known as high blood pressure, is a serious medical condition that affects billions of people worldwide. Nebivolol hydrochloride, a & beta;1-adrenergic blocking agent, is used by the oral route in the treatment of hypertension and congestive heart failure. However, its lipophilic nature and poor aqueous solubility restricts its oral bioavailability. To overcome limitations related with conventional oral formulations of the drug, uncoated and polymer-coated liposomes were developed and evaluated. Liposomes loaded with nebivolol hydrochloride were prepared by thin-film hydration method and characterized. The influence of chitosan or pluronic (F127) coating on the liposome properties was evaluated in terms of physicochemical characteristics, stability in simulated gastrointestinal fluids, mucin interaction, in vitro drug release and cytotoxicity studies. It was observed that coating the liposomes with either chitosan or pluronic affected the size, surface charge and encapsulation efficiency of the formulations. The surface morphology studies confirmed the vesicular shape of liposomes. The results obtained indicated that both polymer-coated liposome formulations maintained their stability in simulated gastrointestinal fluids and showed significant in vitro interaction with mucin. Polymer-coated liposome formulations showed much better cumulative release of the drug than uncoated liposomes. No aggregation was observed at the end of four-week storage period and low toxicity in Caco-2 cells was measured. The results demonstrated that polymer coating of liposomes could enhance the in vitro release of nebivolol hydrochloride and interaction with mucin following oral administration and might be attractive alternative nanocarriers to traditional oral formulations.
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    Induction of humoral and cell-mediated immunity in mice by chitosan-curdlan composite nanoparticles administered intranasally and subcutaneously
    (Editions de Sante, 2023) Sessevmez, Melike; Sinani, Genada; Okyar, Alper; Alpar, Hazire Oya; Cevher, Erdal
    Infectious diseases seriously threaten human life. The need for novel delivery systems and adjuvants suitable to be used in clinic for antigens remains a challenge. Among various attempts that have been made to provide optimum immune responses for protein antigens with poor immunogenicity, polymeric nanoparticles offer great opportunities. In this study, carboxymethyl curdlan (CMC) as a polyanionic polymer and chitosan chloride (CC) and N-trimethyl chitosan (TMC) as polycationic polymers were synthesised in-house and composite nanoparticles (CC-CMC-BSA and TMC-CMC-BSA) loaded with bovine serum albumin (BSA) as a model antigen were prepared via polyelectrolyte complexation and reported here for the first time. Nanoparticles with an average size ranging from 153 nm to 615 nm, positive surface charge (from +24 mV to +55 mV) and encapsulation efficiency as high as 90% were obtained depending on the concentration of polymers in the formulation. The nanoparticles showed good physical stability for three months and low toxicity in Calu-3 and A549 cells. Furthermore, SDS integrity of antigen was maintained. In vivo studies in mice indicated that nasal and subcutaneous administration of composite nanoparticles could provide long-term humoral and cellular immunity as determined by serum antibody titres (IgG, IgG1, IgG2a) and cytokine (IL-2, IL-4, IL-6, IL-10 and IFN-γ) levels. Elevated sIgA levels after nasal administration of the nanoparticles showed that mucosal immunity was successfully stimulated. These findings suggest that chitosan-curdlan composite nanoparticles show optimum properties to be used as nanovaccine for nasal immunisation of protein antigens.
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    Modified chitosan-based nanoadjuvants enhance immunogenicity of protein antigens after mucosal vaccination
    (Elsevier, 2019) Sinani, Genada; Sessevmez, Melike; Gök, M. Koray; Özgümüş, Saadet; Alpar, H. Oya; Cevher, Erdal
    Nasal vaccination is considered to be an effective and convenient way of increasing immune responses both systemically and locally. Although various nanovaccine carriers have been introduced as potential immune adjuvants, further improvements are still needed before they can be taken to clinical usage. Chitosan-based nanovaccine carriers are one of the most widely studied adjuvants, owing to the ability of chitosan to open tight junctions between nasal epithelial cells and enhance particle uptake as well as its inherent immune activating role. In present study, bovine serum albumin (BSA) loaded nanoparticles were prepared using novel aminated (aChi) and aminated plus thiolated chitosan (atChi) polymers, to further enhance mucoadhesiveness and adjuvanticity of the vaccine system by improving electrostatic interactions of polymers with negatively charged glycoproteins. Nanocarriers with optimum size and surface charge, high encapsulation efficiency of model antigen and good stability were developed. Negligible toxicity was observed in Calu-3 and A549 cell lines. In vivo studies, revealed high levels of systemic antibodies (IgG, IgG(1) and IgG(2a)) throughout the study and presence of sIgA in vaginal washes showed that common mucosal system was successfully stimulated. Cytokine levels indicated a mixed Th1/Th2 immune response. A shift towards cellular immune responses was observed after nasal immunisation with antigen loaded nanoparticle formulations. These nanoparticles exhibit great potential for nasal application of vaccines.
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    Nasal vaccination with poly(beta-amino ester)-poly(D,L-lactide-co-lycolide) hybrid nanoparticles
    (Elsevier Science Bv, 2017) Sinani, Genada; Sessevmez, Melike; Gök, M. Koray; Özgümüş, Saadet; Okyar, Alper; Alpar, H. Oya; Cevher, Erdal
    Mucosal vaccination stimulates both mucosal and systemic immunity. However, mucosal applications of vaccine antigens in their free form generally result in poor systemic immune responses and need adjuvantation. In this study, bovine serum albumin loaded, new hybridised poly(beta-amino ester)-poly( D, Llactide-co-glycolide) nanoparticles were prepared by double emulsion-solvent evaporation method, characterised and evaluated in vivo as nasal vaccine carriers. Cationic spherical particles with a mean size of 240 nm, good physical stability and high encapsulation efficiency were obtained. Protein structure was not affected throughout preparation and minimal toxicity was shown in Calu-3 and A549 cells. Nasal vaccination with these nanoparticles revealed markedly higher humoral immune responses compared with free antigen following intranasal and subcutaneous immunisation. Mucosal immune response was also stimulated and cytokine titres indicated that Th1 and Th2 pathways were successfully activated. This study shows that the formulated hybrid nanoparticles can be a promising carrier for nasal immunisation of poor antigenic proteins. (C) 2017 Elsevier B.V. All rights reserved.
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    Oral tablet formulations containing cyclodextrin complexes of poorly water soluble cefdinir to enhance its bioavailability
    (Elsevier, 2020) Morina, Deniz; Sessevmez, Melike; Sinani, Genada; Mulazimoğlu, Lutfiye; Cevher, Erdal
    Cefdinir (CFD) is an oral cephalosporin antibiotic commonly used in the treatment of community-acquired infections. The oral bioavailability of CFD is limited due to its poor aqueous solubility. Cyclodextrins (CyDs) and their chemically modified derivatives are used in the pharmaceutical field to form inclusion complexes with drug molecules to improve their aqueous solubility as well as stability and to prevent side effects. In this study, CFD was complexed with CyDs such as beta-cyclodextrin (beta-CyD), gamma-cyclodextrin (gamma-CyD), hydroxypropyl-beta-cyclodextrin (HP-beta-CyD), and sulphobutyl ether 7-beta-cyclodextrin (SBE7-beta-CyD) to increase its aqueous solubility and to reduce its side effects without decreasing the antimicrobial activity. Phase solubility studies were performed and the stability constant of the CFD:CyD inclusion complexes was determined. The solubility of CFD was increased after complexation with CyDs as indicated by phase solubility studies, in the order beta-CD < HP-beta-CyD < gamma-CyD < SBE7-beta-CyD, a result that depends on the conditions of complexation formation. Complex formation between CFD and CyDs was evaluated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and powder x-ray diffractometry (PXRD) studies. The antimicrobial activity of the complexes against Staphylococcus aureus and Escherichia coli strains were evaluated and the strains showed higher susceptibility to CFD:HP-beta-CyD complex. Oral tablet formulations were fabricated using Avicel (R) PH 102 or Ludipress (R) as direct compression agent and magnesium stearate as lubricant. Using CFD:HP-beta-CyD complex in tablets significantly improved the dissolution rate of the drug when compared with that of formulation containing CFD alone.
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    Polymeric-Micelle-Based delivery systems for nucleic acids
    (2023) Sinani, Genada; Durgun, Meltem Ezgi; Cevher, Erdal; Özsoy, Yıldız
    Nucleic acids can modulate gene expression specifically. They are increasingly being utilized and show huge potential for the prevention or treatment of various diseases. However, the clinical translation of nucleic acids faces many challenges due to their rapid clearance after administration, low stability in physiological fluids and limited cellular uptake, which is associated with an inability to reach the intracellular target site and poor efficacy. For many years, tremendous efforts have been made to design appropriate delivery systems that enable the safe and effective delivery of nucleic acids at the target site to achieve high therapeutic outcomes. Among the different delivery platforms investigated, polymeric micelles have emerged as suitable delivery vehicles due to the versatility of their structures and the possibility to tailor their composition for overcoming extracellular and intracellular barriers, thus enhancing therapeutic efficacy. Many strategies, such as the addition of stimuli-sensitive groups or specific ligands, can be used to facilitate the delivery of various nucleic acids and improve targeting and accumulation at the site of action while protecting nucleic acids from degradation and promoting their cellular uptake. Furthermore, polymeric micelles can be used to deliver both chemotherapeutic drugs and nucleic acid therapeutics simultaneously to achieve synergistic combination treatment. This review focuses on the design approaches and current developments in polymeric micelles for the delivery of nucleic acids. The different preparation methods and characteristic features of polymeric micelles are covered. The current state of the art of polymeric micelles as carriers for nucleic acids is discussed while highlighting the delivery challenges of nucleic acids and how to overcome them and how to improve the safety and efficacy of nucleic acids after local or systemic administration.