Browsing by Subject "Drug synthesis"

Filter results by typing the first few letters
Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    Injectable in situ forming microparticles: A novel drug delivery system
    (2012) Yapar, E. A.; Inal, Ö.; Özkan, Y.; Baykara, T.
    Pharmaceutical formulation research has recently been focusing on delivery systems which provide long therapeutic effects and reduced side effects, and involving simplified production stages and facilitated application process. In situ forming microparticle (ISM) systems, one of the latest approach in this field, offer a new encapsulation technique and meet the objectives stated above. Factors such as the carrier used to form the multiparticles, amount and type of drug and the vehicle type can be taken as the main performance criteria for these systems. Ongoing studies have shown that this new multiparticulate drug delivery system is suitable for achieving new implant delivery system with low risk of dose-dumping, capable of being modulated to exhibit varying release patterns, reproducible, easily applicable and welltolerated compared with classically surgical implants.
  • Thumbnail Image
    ItemOpen Access
    Quinoides and VEGFR2 TKIs influence the fate of hepatocellular carcinoma and its cancer stem cells
    (Royal Society of Chemistry, 2017) Kahraman, D. C.; Hanquet, G.; Jeanmart, L.; Lanners, S.; Šramel, P.; Boháč, A.; Cetin-Atalay, R.
    Bioactivities of quinoides 1–5 and VEGFR2 TKIs 6–10 in hepatocellular cancer (HCC) and cancer stem cells (HCSCs) were studied. The compounds exhibited IC50 values in μM concentrations in HCC cells. Quinoide 3 was able to eradicate cancer stem cells, similar to the action of the stem cell inhibitor DAPT. However, the more cytotoxic VEFGR TKIs (IC50: 0.4–3.0 μM) including sorafenib, which is the only FDA approved drug for the treatment of HCC, enriched the hepatocellular cancer stem cell population by 2–3 fold after treatment. An aggressiveness factor (AF) was proposed to quantify the characteristics of drug candidates for their ability to eradicate the CSC subpopulation. Considering the tumour heterogeneity and marker positive cancer stem cell like subpopulation enrichment upon treatments in patients, this study emphasises the importance of the chemotherapeutic agent choice acting differentially on all the subpopulations including marker-positive CSCs.
  • Thumbnail Image
    ItemOpen Access
    Theoretical analysis of substituent effects on building blocks of conducting polymers: 3, 4'-substituted bithiophenes
    (American Chemical Society, 1999) Salzner, U.; Kızıltepe, T.
    Substituents are widely used to modify the properties of conducting polymers. To study substituent effects on energy levels and energy gaps systematically, CH3-, OH-, NH2-, CN-, and CCH-substituted bithiophenes were examined with density functional theory and NBO analysis. Total charges and :r-electron densities were analyzed separately to examine π- and σ-effects. Second-order perturbation theory was used to quantify conjugation in terms of orbital interactions. NBO orbital energies were employed to investigate the effect of alternating donor-acceptor substitution. Substituents in 3- and 4- positions shift HOMO and LUMO levels in parallel and hardly influence HOMO- LUMO gaps. For level shifting the π-donating and π-accepting abilities are most important; electronegativity mainly influences the σ-orbitals and is less crucial in determining energy gaps. Alternating donor-acceptor substitution leads to HOMO and LUMO energies that are average between those of the parent systems and has little effect on energy gaps.