Yazar "Cevher, Erdal" seçeneğine göre listele

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  • Küçük Resim
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    An alternative approach to wound healing field; New composite films from natural polymers for Mupirocin dermal delivery
    (Elsevier, 2019) Okur, Neslihan Üstündağ; Hökenek, Nesrin; Okur, Mehmet Evren; Ayla, Şule; Yoltaş, Ayşegül; Siafaka, Panoraia I.; Cevher, Erdal
    In this study, novel adhesive films were prepared for Mupirocin dermal delivery. Natural polymers as chitosan, sodium alginate and carbopol were used for films development to evaluate possible interactions and drug release properties. Solvent evaporation method was used for films preparation. Preliminary studies involved FT-IR spectroscopy and Scanning Electron Microscopy to specify interactions and morphology. Thickness, tensile strength and water uptake in phosphate buffer saline were evaluated whereas in vitro release studies were also performed. In vitro drug release studies demonstrated that mupirocin release was improved. Ex vivo bioadhesion and permeation studies using Balb-c mice were performed to check the suitability of the films. Antimicrobial ability was evaluated by agar well diffusion tests. Finally, excisional wound model applied to test the wound healing effect and evaluated macroscopic and histopathologically. One formulation was found more effective compared to the market product for wound healing at Balb-c mice.
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    Chitosan-based buccal mucoadhesive bilayer tablets enhance the bioavailability of tizanidine hydrochloride by bypassing the first-pass metabolism
    (2024) Arpa, Muhammet Davut; Üstündağ Okur, Neslihan; Gök, Mehmet Koray; Cevher, Erdal
    Tizanidine hydrochloride (TZN) is an antimuscarinic agent used in the treatment of pain-related spasms, multiple sclerosis, and stroke-related spasticity. It has low oral bioavailability (40 %) due to excessive first-pass metabolism in the liver. The aim of this project was to enhance the systemic bioavailability of TZN by developing buccal mucoadhesive bilayer tablet formulations using chitosan salts with molecular weights of 136 kDa (7 cP) and 169 kDa (10 cP). Structural characterisation of chitosans and their salts was performed by FTIR, 1H NMR, DSC, TGA, and XRD analyses. Soluble chitosan salts, chitosan glutamate and chitosan chloride, for the adhesive layer, and insoluble ethyl cellulose for the impermeable backing layer were selected as polymers to fabricate the buccal tablets by direct compression method. The tablets containing TZN demonstrated high swelling and good mucoadhesion characteristics as well as released all the drug within 8 h. While TC10, formulated with 10 cP chitosan chloride, showed the highest swelling properties, TG10, prepared with 10 cP chitosan glutamate, exhibited the highest mucoadhesion. Chitosan glutamate tablets (TG7 and TG10) demonstrated better mucoadhesive characteristics and stability than chitosan chloride ones (TC7 and TC10) in the buccal medium based on the results of swelling and drug release studies. The permeability studies performed by Franz diffusion cell demonstrated that the amount of TZN passing through the bovine buccal mucosa was between 13.4 and 14.4 %. Stability studies conducted at 5 ± 2 °C, 25 ± 2 °C and 40 ± 2 °C for 6 months showed that no changes in the content uniformity and pH were observed. The in vivo comparative bioavailability studies in female New Zealand rabbits were performed and TZN-containing buccal mucoadhesive bilayer tablets fabricated with both chloride (TC10) and glutamate (TG10) salts of chitosan demonstrated three times higher bioavailability than the commercial TZN product (Sirdalud® oral tablet) administered by the gastrointestinal route.
  • Küçük Resim
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    Chitosan-based buccal mucoadhesive patches to enhance the systemic bioavailability of tizanidine
    (Elsevier B.V., 2023) Arpa, Muhammet Davut; Üstündağ Okur, Neslihan; Gök, Mehmet Koray; Özgümüş, Saadet; Cevher, Erdal
    Tizanidine hydrochloride (TZN) is a muscle relaxant used to treat a variety of disorders such as painful muscle spasms and chronic spasticity. TZN has low oral bioavailability due to extensive first-pass metabolism and is used orally at a dose of 6–24 mg per day. In the present study, buccal patches were prepared by solvent casting method using chitosan glutamate (Chi-Glu) and novel chitosan azelate (Chi-Aze) which was synthesised in-house for the first time, to enhance the bioavailability of TZN by bypassing first-pass metabolism. The characterisation, mucoadhesion and drug release studies were performed. Chi-Aze patches retained their integrity longer in the buccal medium and showed higher ex vivo drug permeability compared to that prepared with Chi-Glu. In vivo studies revealed that buccal formulation fabricated with Chi-Aze (3%) showed approx 3 times more bioavailability than the orally administered commercial product. Results of the studies indicate that Chi-Aze, prepared by conjugation of chitosan and a fatty acid, the patch formulation is a promising buccal mucoadhesive system due to the physical stability in buccal medium, the good mucoadhesiveness and the high TZN bioavailability. Moreover, Chi-Aze patch might be an alternative to oral formulations of TZN to reduce the dose and frequency of drug administration.