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    Effect of precipitation inhibitors on supersaturation and solubility of furosemide
    (Marmara Univ, 2021) Gulsun, Tugba; Ozturk, Naile; Kara, Asli; Sahin, Selma; Vural, Imran
    Furosemide is a widely used diuretic drug for the treatment of edema associated with heart, liver cirrhosis, renal diseases and hypertension. It is a Class IV drug with low aqueous solubility and low permeability according to Biopharmaceutics Classification System (BCS). Furosemide was chosen as a model drug to examine the effect of polymeric precipitation inhibitors (PPIs) on the supersaturation and solubility. Solubility and concentration change of furosemide as a function of time at pH 1.2 and 6.8 were determined to show the effects of PPIs on furosemide solubility. The 24 h equilibrium solubility of furosemide was 0.017 +/- 0.004 and 3.62 +/- 0.201 mg/mL at pH 1.2 and pH 6.8 buffer solutions, respectively. PPI type and concentration (0.05%, 0.25%) did not increase furosemide solubility at pH 1.2. However, both hydroxypropylmethylcellulose (HPMC) and polyvinylpyrrolidoneK17 (PVPK17) at two concentrations increased furosemide solubility at pH 1.2 and 6.8. In addition, viscosity of solutions was in the range of 2.2-3.7 centipoise, and it was not influenced by PPIs concentrations. Our results showed that designing supersaturated formulations using PPIs can be useful and promising to enhance solubility of furosemide.
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    Evaluation of Antitumor Activity of a Non-Steroidal Anti-Inflammatory Drug, Ibuprofen, by a Targeted Nanoparticulate System
    (Colegio Farmaceuticos Provincia De Buenos Aires, 2017) Ozturk, Naile; Kara, Asli; Vural, Imran
    In this study we aimed to develop a new targeted nanoparticulate system to obtain site specific delivery of ibuprofen and to determine its antitumor efficiency. The potential effect of ibuprofen as an antitumor agent was investigated on breast cancer cells based on a targeted delivery system. Ibuprofen was encapsulated to poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles. PLGA nanoparticles were fabricated by nanoprecipitation method and optimized in terms of certain parameters. Then, 520C9 monoclonal antibody (mAb) was chemically conjugated to carboxylic acid end group of PLGA nanoparticles (NPs) that specifically targeted human breast adenocarcinoma cell line (MCF-7), NP-mAb combined Ibuprofen encapsulated formulations were evaluated on characterization of particle size, encapsulation efficiency, drug loading capacity, and antitumor activity. The results demonstrated that optimized Ibuprofen loaded PLGA nanoparticles prepared by nanoprecipitation technique had an ideal particle size and polydispersity index. The encapsulation efficiency of optimized nanoparticles was relatively high, 92.9 +/- 9.0 %. Also, this system had significantly reduced the cell viability on MCF-7 cell line when compared with free ibuprofen solution at the same concentration. Above all, antibody-conjugated nanoparticles showed lower cell viability (12%) than the non-targeted system. Results indicated that ibuprofen-loaded nanoparticles had significant antitumor activity on MCF-7 cells even at relatively low concentrations. mAb conjugated drug-loaded nanoparticles were successfully fabricated and this system might be a promising approach for delivery of ibuprofen in treatment of breast cancer.
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    Exploiting ionisable nature of PEtOx-co-PEI to prepare pH sensitive, doxorubicin-loaded micelles
    (Taylor & Francis Ltd, 2020) Ozturk, Naile; Kara, Asli; Gulyuz, Sevgi; Ozkose, Umut Ugur; Tasdelen, Mehmet Atilla; Bozkir, Asuman; Yilmaz, Ozgur
    Aims This study was conducted to evaluate block copolymers containing two different poly(ethyleneimine) (PEI) amounts, as new pH-sensitive micellar delivery systems for doxorubicin. Methods Micelles were prepared with block copolymers consisting of poly(2-ethyl-2-oxazoline)-co-poly(ethyleneimine) (PEtOx-co-PEI) and poly(epsilon-caprolactone) (PCL) as hydrophilic and hydrophobic blocks, respectively. Doxorubicin loading, micelle size, pH-dependent drug release, and in vitro cytotoxicity on MCF-7 cells were investigated. Results The average size of drug-loaded micelles was under 100 nm and drug loading was between 10.7% and 48.3% (w/w). pH-sensitive drug release was more pronounced (84.7% and 68.9% (w/w) of drug was released at pH 5.0 and pH 7.4, respectively) for the micelles of the copolymer with the lowest PEI amount. The cell viability of doxorubicin-loaded micelles which were prepared by the copolymer with the lowest PEI amount was 28-33% at 72 h. Conclusions PEtOx-co-PEI-b-PCL micelles of this copolymer were found to be stable and effective pH-sensitive nano-sized carriers for doxorubicin delivery.
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    Formulation and In Vitro Evaluation of Telmisartan Nanoparticles Prepared by Emulsion-Solvent Evaporation Technique
    (Turkish Pharmacists Assoc, 2020) Ozturk, Naile; Kara, Asli; Vural, Imran
    Objectives: Telmisartan (TLM) is an antihypertensive drug that has been shown to have antiproliferative effects on cancer cells. It has low solubility and suboptimal oral bioavailability. To investigate the potential anticancer effect of TLM on breast cancer cells, poly (D, L-lactide) (PLA) nanoparticles were formulated with the benefit of improving its solubility. Materials and Methods: TLM-loaded PLA nanoparticles were prepared by emulsion solvent evaporation. The effects of sonication time and polymer:drug ratio on nanoparticle size and drug encapsulation were investigated. TLM-loaded nanoparticles were tested against MCF-7 and MDA-MB-231 breast cancer cell lines for antiproliferative effects. Results: Nanoparticles with mean particle size 272 nm and 79% encapsulation efficiency were obtained. Sustained release TLM nanoparticles (40% in 24 h) decreased cell viability to 45% for MCF-7 cells at 72 h, even at the lowest TLM concentration, indicating better anticancer efficiency than TLM solution. Conclusion: TLM nanoparticles could be potential anticancer agents for breast cancer and deserve further studies.
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    Poly(2-ethyl-2-oxazoline-co-ethyleneimine)-block-poly(?-caprolactone) based micelles: synthesis, characterization, peptide conjugation and cytotoxic activity
    (Royal Soc Chemistry, 2021) Gulyuz, Sevgi; Ozkose, Umut Ugur; Khalily, Melek Parlak; Kesici, Mehmet Seckin; Kocak, Polen; Bolat, Zeynep Busra; Kara, Asli
    Here we present self-assembled polymeric micelles as potential delivery systems for therapeutic agents with highly tunable properties. The major goal of this study is to design breast and prostate cancer specific targeting peptide modified PEtOx-co-PEI-b-PCL block copolymer based micelles as a targetable carrier system in cancer treatment. For this, a series of micelles based on poly(2-ethyl-2-oxazoline)-co-polyethyleneimine-block-poly(epsilon-caprolactone) [P(EtOx-co-EI)-b-PCL] copolymers with two different proportions of PEI (30% and 60% hydrolysis degrees of PEtOx) were successfully prepared. The block copolymers were synthesized using a combination of living cationic ring-opening polymerization and a copper(i)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction. Then, peptide 18 and peptide 563 were conjugated to P(EtOx-co-EI)-b-PCL through a thiol-ene click-type reaction to obtain the desired tumor-targeting. The structural properties of the copolymers were confirmed by H-1 NMR, FT-IR, UV-Vis spectrometry and GPC. Peptide and non-peptide-conjugated micelles with particle sizes between 82 +/- 0.6 and 170 +/- 10.7 nm were obtained by self-assembly with two different chain lengths of PEI blocks. The micelles containing the 60% PEI block showed increased zeta potential values. The cytotoxicity of the copolymers was evaluated under in vitro conditions. Overall, our results indicate that the micelles prepared with peptide-conjugated block copolymers can be used as potential nanocarriers for targeted therapeutic delivery systems.