The topic of the invited lecture was the influence of molecular polymer structure on the drug release from different dosage forms. In the case of complex anionic polyelectrolyte like xanthan (XAN); the polymer structure in aqueous environment is depends mostly on medium characteristics, whereas in the case of simple nonionic poly(vinyl alcohol) (PVA) the structure or polymer organization is influenced mostly by polymer and drug concentration. XAN adopts single chain conformation in water, whereas at pH 1.2 rigid double stranded structures are formed. The pentoxifylline release studies revealed faster drug release from tablets in pH 1.2 medium compared to pure water, even though the XAN molecular structure was more rigid. The diffusion barrier was thinner and, therefore, the release faster compared to water medium. The organization of PVA within the colloid solution has a great impact on nanofiber formation. The smooth nanofibers can be produced only, when PVA molecules form properly firm internal structures in solution, which can be oriented in the direction of applied electric field, enabling complete polymer elongation during electrospinning. The addition of sodium naproxenate (SN) influences on some PVA solution characteristics (density, conductivity, kinematic viscosity) in concentration dependent manner, meaning bigger changes with higher drug concentration. However, the concentration up to 10% did not change significantly the PVA structure in solution and did not influence on the nanofiber formation. The drug release from nanofibers was almost immediate regardless to the ratio between PVA and SN in nanofibers. Therefore, the influence of polymer structure on drug release from tablets has been proven for XAN, whereas in the case of PVA nanofibers the straight forward relationship has not been confirmed.
B.04 Guest lecture
COBISS.SI-ID: 3536753In the scope of the project 2 master thesis and 4 diploma thesis have been finished in the year 2013, indicating the direct transfer of the generated knowledge on young experts. Master thesis: - BERTONCELJ, Valentina. Formulation of nanofibers with growth factors and their effect on cell response in vitro [COBISS.SI-ID 3524977] - ZAVALOKA, Helena. Investigation of polyvinil alcohol nanofibers as drug delivery systems for nonsteroidal anti-inflammatory drugs [COBISS.SI-ID 3576177] Diploma thesis: - ERJAVEC, Tomaž. Preparation of two-layer nanofibers using electrospinning with coaxial nozzle [COBISS.SI-ID 3412081] - NOVAK, Ana. Preparation and evaluation of aligned elextrospun poly(vinyl) alcohol nanofibers. Ljubljana [COBISS.SI-ID 3517041] - JERAJ, Žiga. Effect of solvents on the formation of polycaprolactone nanofibers produced by electrospinning. [COBISS.SI-ID 3524209] ZUPANČIČ, Alenka. Influence of various added salts of the physical-chemical properties of poly(vinylalcohol) solution[COBISS.SI-ID 3487345]
D.10 Educational activities
COBISS.SI-ID: 3524209Dr. Romana Ročic recived Krka Prize for her doctoral thesis, which was prepared under the supervision of prof. dr. Juliana Kristl and co-supervision of assoc. prof. dr. Saša Baumgartner. The PhD thesis is the result of research performed in the scope of the project. It represents a comprehensive knowledge generated in the field of physico-chemical characterization of polymer solutions as well as production and final evaluation of the electrospun polymer nanofibres intended for biomedical applications. Scientific findings covered in the scope of the award-winning PhD thesis were published in 8 articles, namely 7 with an impact factor (5 original scientific and 2 review articles).
E.01 National awards
COBISS.SI-ID: 3553905