Browsing by Subject "Cyclodextrin inclusion complexes"

Now showing 1 - 4 of 4

Open Access
Antibacterial electrospun nanofibers from triclosan/cyclodextrin inclusion complexes
(Elsevier, 2014) Celebioglu A.; Umu, O. C. O.; Tekinay, T.; Uyar, Tamer
The electrospinning of nanofibers (NF) from cyclodextrin inclusion complexes (CD-IC) with an antibacterial agent (triclosan) was achieved without using any carrier polymeric matrix. Polymer-free triclosan/CD-IC NF were electrospun from highly concentrated (160% CD, w/w) aqueous triclosan/CD-IC suspension by using two types of chemically modified CD; hydroxypropyl-beta-cyclodextrin (HPβCD) and hydroxypropyl-gamma-cyclodextrin (HPγCD). The morphological characterization of the electrospun triclosan/CD-IC NF by SEM elucidated that the triclosan/HPβCD-IC NF and triclosan/HPγCD-IC NF were bead-free having average fiber diameter of 520±250nm and 1100±660nm, respectively. The presence of triclosan and the formation of triclosan/CD-IC within the fiber structure were confirmed by 1H-NMR, FTIR, XRD, DSC, and TGA studies. The initial 1:1molar ratio of the triclosan:CD was kept for triclosan/HPβCD-IC NF after the electrospinning and whereas 0.7:1molar ratio was observed for triclosan/HPγCD-IC NF and some uncomplexed triclosan was detected suggesting that the complexation efficiency of triclosan with HPγCD was lower than that of HPβCD. The antibacterial properties of triclosan/CD-IC NF were tested against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. It was observed that triclosan/HPβCD-IC NF and triclosan/HPγCD-IC NF showed better antibacterial activity against both bacteria compared to uncomplexed pure triclosan.
Open Access
Encapsulation of active agents in electrospun nanofibers/nanowebs
(The Fiber Society, 2013) Kayaci, Fatma; Aytac, Zeynep; Celebioglu, Asli; Uyar, Tamer
In this study, we produce functional nanofibers/nanowebs containing active agents such as essential oils, antibacterials, antioxidants, flavors/fragrances via electrospinning technique. The encapsulation of these active agents into electrospun nanofibers/nanowebs was quite possible, however, their stability and/or shelf-life was limited due to their volatile nature. Nevertheless, by forming cyclodextrin inclusion complexes (CD-IC) with these active agents and incorporating CD-IC into electrospun nanofibers/nanowebs, we achieved high temperature stability, slow release and prolonged shelf-life for these active agents. These functional electrospun nanofibers/nanowebs containing active agents can be quite applicable in active food packaging, textiles, biotechnology, etc.
Open Access
Fast-dissolving electrospun nanofibrous films of paracetamol/cyclodextrin inclusion complexes
(Elsevier, 2019) Yıldız, Zehra İrem; Uyar, Tamer
The free-standing and fast-dissolving nanofibrous films from inclusion complexes (ICs) of paracetamol with two different cyclodextrins, hydroxypropyl-beta-cyclodextrin (HPβCD) and sulfobutylether-beta-cyclodextrin (SBEβ-CD) were produced through electrospinning without using polymer matrix. The morphology of the nanofibers (NFs) was uniform and bead-free as confirmed by scanning electron microscopy imaging. The chemical, structural and thermal characteristics of the electrospun paracetamol/CD-IC NFs were investigated by X-ray diffractometry, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermal gravimetric analyzer and proton nuclear magnetic resonance. The aforementioned methods indicated the successful formation of ICs of paracetamol with both CD types (HPβCD and SBE-β-CD). Besides, paracetamol/CD-IC NFs exhibited different features and properties from pristine paracetamol. For instance, the crystalline state of pristine paracetamol was transformed into amorphous state by CD-IC NFs formation which is important for the water-solubility increment of the drug molecules. Moreover, thermal studies indicated that paracetamol became thermally more stable in CD-IC NFs. The molar ratio of paracetamol:CD was found as ~0.85:1.00 for paracetamol/HPβCD-IC NFs and ~0.80:1.00 for paracetamol/SBE-β-CD-IC NFs. The dissolution behavior of paracetamol/CD-IC nanofibrous films was examined by exposing them to water. The electrospun paracetamol/CD-IC nanofibrous films showed fast-dissolving character in water due to the CD-ICs formation and high surface area of nanofibrous structure.
Open Access
Molecular encapsulation of cinnamaldehyde within cyclodextrin inclusion complex electrospun nanofibers: fast-dissolution, enhanced water solubility, high temperature stability, and antibacterial activity of cinnamaldehyde
(American Chemical Society, 2019) Yıldız, Zehra İrem; Kılıç, Mehmet Emin; Durgun, Engin; Uyar, Tamer
The electrospinning of nanofibers (NFs) of cinnamaldehyde inclusion complexes (ICs) with two different hydroxypropylated cyclodextrins (CDs), hydroxypropyl-β-cyclodextrin (HP-β-CD) and hydroxypropyl-γ-cyclodextrin (HP-γ-CD), was successfully performed in order to produce cinnamaldehyde/CD-IC NFs without using an additional polymer matrix. The inclusion complexation between cinnamaldehyde and hydroxypropylated CDs was studied by computational molecular modeling, and the results suggested that HP-β-CD and HP-γ-CD can be inclusion complexed with cinnamaldehyde at 1:1 and 2:1 (cinnamaldehyde/CD) molar ratios. Additionally, molecular modeling and phase solubility studies showed that water solubility of cinnamaldehyde dramatically increases with cyclodextrin inclusion complex (CD-IC) formation. The HP-β-CD has shown slightly stronger binding with cinnamaldehyde when compared to HP-γ-CD for cinnamaldehyde/CD-IC. Although cinnamaldehyde is a highly volatile compound, it was effectively preserved with high loading by the cinnamaldehyde/CD-IC NFs. It was also observed that cinnamaldehyde has shown much higher temperature stability in cinnamaldehyde/CD-IC NFs compared to uncomplexed cinnamaldehyde because of the inclusion complexation state of cinnamaldehyde within the hydroxypropylated CD cavity. Moreover, cinnamaldehyde still has kept its antibacterial activity in cinnamaldehyde/CD-IC NF samples when tested against Escherichia coli. In addition, cinnamaldehyde/CD-IC NF mats were fast-dissolving in water, even though pure cinnamaldehyde has a water-insoluble nature. In brief, self-standing nanofibrous mats of electrospun cinnamaldehyde/CD-IC NFs are potentially applicable in food, oral-care, healthcare, and pharmaceutics because of their fast-dissolving character, enhanced water solubility, stability at elevated temperature, and promising antibacterial activity.