Person: UĞURLU, TİMUÇİN
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UĞURLU
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TİMUÇİN
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Publication Metadata only Scintigraphic evaluation of colon targeting pectin-HPMC tablets in healthy volunteers(ELSEVIER SCIENCE BV, 2009) UĞURLU, TİMUÇİN; Hodges, L. A.; Connolly, S. M.; Band, J.; O'Mahony, B.; Ugurlu, T.; Turkoglu, M.; Wilson, C. G.; Stevens, H. N. E.The in vivo evaluation of colon-targeting tablets was conducted in six healthy male volunteers. A pectin-hydroxypropyl methylcellulose coating was compressed onto core tablets labelled with 4 MBq (99m)Tc-DTPA. The tablets released in the colon in all subjects: three in the ascending colon (AC) and three in the transverse colon (TC). Tablets that released in the TC had reached the AC before or just after food (Group A). The other three tablets released immediately upon AC entry at least 1.5 h post-meal (Group 13). Release onset for Group B was earlier than Group A (343 min vs 448 min). Group B tablets exhibited a clear residence period at the ileocaecal junction (ICJ) which was not observed in Group A. Prolonged residence at the ICJ is assumed to have increased hydration of the hydrogel layer surrounding the core tablet. Forces applied as the tablets progressed through the ICJ may have disrupted the hydrogel layer sufficiently to initiate radiolabel release. Conversely, Group A tablets moved rapidly through the AC to the TC, possibly minimising contact times with water pockets. Inadequate prior hydration of the hydrogel layer preventing access of pectinolytic enzymes and reduced fluid availability in the TC may have retarded tablet disintegration and radiolabel diffusion. (C) 2008 Elsevier B.V. All rights reserved.Publication Metadata only Nanocarriers: Novel Approaches to Oral Delivery of Insulin(MARMARA UNIV, INST HEALTH SCIENCES, 2017) KERİMOĞLU, OYA; Ozer, Setenay; Kerimoglu, Oya; Ugurlu, TimucinDiabetes is among the major chronic diseases at present, and no medication has been developed that can replace the roles of endogenous insulin, especially for type 1 diabetes patients. However, insulin can be frequently administered by the subcutaneous route as a protein macromolecule because enzymatic and absorption-associated problems. It leads to immunogenic symptoms, adipose tissue complaints such as lipodystrophy, and hyperinsulinemia risks because of pharmacokinetic properties that do exactly overlap with those of endogenous insulin. In a remarkable number of patients, failure to attain permanent glycemic control by subcutaneous insulin treatment has shown by clinical trials based on noncompliance. Oral drug administration has always been the most preferred administration pathway for drugs with high patient compliance and convenience. Difficulties in the use of subcutaneous insulin have prompted scientists to find solutions for the oral administration of insulin. Similar to many other fields, nanotechnology has recently come to the fore in the pharmaceutical field. Compared with conventional systems, nanopharmaceuticals are drug delivery systems that enable promoted absorption, protection of the active ingredient from the external environment, lower dose applications, higher bioavailability, controlled release, and prolonged residence time. In vitro and in vivo studies have been performed with varied nanopharmaceutical systems in order to administer insulin orally for this purpose.Publication Metadata only Colonic delivery of compression coated nisin tablets using pectin/HPMC polymer mixture(ELSEVIER, 2007) GÜRBÜZ, BURÇAK; Ugurlu, Timucin; Turkoglu, Murat; Gurer, Umran Soyogul; Akarsu, Burcak GurbuzNisin containing pectin/HPMC compression coated tablets were prepared and their in vitro behavior tested for colonic delivery. Nisin is a 34-amino-acid residue long, heat stable peptide belonging to the group A lantibiotics with wide antimicrobial activity against Grampositive bacteria. The invention can be useful for treating colonic infectious diseases such as by Clostridium difficile, and also by colonization of vancomycin-resistant enterococci. In this study, each 100 mg core tablet of nisin was compression coated with 100% pectin, 90% pectin-10% HPMC, 85% pectin-15% HPMC, 80% pectin-20% HPMC 75% pectin-25% HPMC, 100% HPMC at a coat weight of 400 mg. The concentration and the activity of nisin were quantified using Well Diffusion Agar Assay. Drug release studies were carried out in pH 3.3 buffer solution. System degradation/erosion experiments were carried out in pH 1.2, 3.3, and 6.8 buffers using a pectinolytic enzyme. The biological activity and NMR studies were performed to assess the stability of nisin during the processing and after the in vitro tests. It was found that pectin alone was not sufficient to protect the nisin containing core tablets. At the end of the 6 h 40% degradation was observed for 100% pectin tablets. HPMC addition required to control the solubility of pectin, a 5% increase in HPMC ratio in pectin/HPMC mixture provided a 2-h lag time for nisin release. Eighty percent pectin-20% HPMC appeared to be an optimum combination for further evaluation. Tablets maintained their integrity during the 6-h dissolution test, approximating the colon arrival times. Nisin was found to be active/stable during processing and after in vitro tests. Effect of polymer hydration on pectin degradation was found to be crucial for the enzyme activity. Sufficiently hydrated pectin degraded faster. The pectin/HPMC envelope was found to be a good delivery system for nisin to be delivered to the colon. (c) 2007 Elsevier B.V. All rights reserved.Publication Open Access Preparation and characterization of poly(lactic-co-glycolic acid) nanoparticles containing TGF-beta 1 and evaluation of in vitro wound healing effect(MARMARA UNIV, 2020-03-12) SEZER, ALİ DEMİR; Soysal, Aysun Celik; Sahbaz, Sevinc; Ugurlu, Timucin; Sezer, Ali Demir( )Wound healing involves many complex mechanisms, and many growth factors are effective in this process. Growth factors are biologically active polypeptides. They perform activities such as cell growth, differentiation, proliferation and migration with molecular cascades by binding to specific receptors. Transforming growth factor stimulates (TGF-beta) different cell types in the wound healing process. Poly(lactic-co-glycolic acid) (PLGA) degradation produces lactate that expedites angiogenesis, activates pro-collagen factors. Therewith, we hypothesized to combine the therapeutic effect of the TGF-beta 1with the positive effect of the drug delivery system including PLGA nanoparticles (TGF beta-PLGA NP). The burst effect decreases as the polymer concentration increases in PLGA nanoparticles. The inhibitory effect of TGF-beta 1 on keratinocytes was reduced by the improved nanoparticle formulations. It showed a proliferative effect of up to 92.5 per cent on fibroblast cells involved in wound healing. Although TGF-beta 1 has an inhibitory effect on keratinocytes, it induces migration both NIH-3T3 and HaCaT cell lines in the scratch assay.