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    Comparison of pharmacodynamics and celiac effects of olmesartan medoxomil formulations by using olmesartan-induced celiac-rat-model
    (2021) Kömesli, Yelda; Ergur, Bekir Uğur; Karasulu, Ercüment
    Introduction: Olmesartan Medoxomil (OM) is an angiotensin receptor blocker and has the adverse effect of celiac like enteropathy which was accepted by the FDA in 2013. This disease is characterized by severe diarrhea, weight loss and enteropathy. Although there are many case reports associated with olmesartan-related enteropathy in humans, it has not been described in a long-term animal model study so far. Aim: We developed a self-microemulsifying drug delivery system (OM-SMEDDS) in our previous study to reduce this side effect of the drug and to enhance bioavailability. Methods: In this study, an artificial hypertension model was established with a dose of 185 μmol /kg L-NAME (N ω-nitro-L-arginine methyl ester) twice in a day intraperitoneally in Wistar albino rats. To determine and compare side effects, the OM-Suspension and OM-SMEDDS were administered at 1.3 mg/kg therapeutic dose during one-month period to the rats. Results: Tension of rats was recorded by measuring from their tails with non invasive blood pressure system. We observed celiac like enteropathy findings like villous atrophy and intraepithelial lymphocytosis and clinical changes like weight loss and severe diarrhea after the treatment with OM-Suspension during one-month experiment. It was also observed that the antihypertensive efficacy of the OM-SMEDDS formulation was higher than the suspension during the experiment, which did not cause enteropathy, diarrhea and weight loss by reducing intestinal exposure. Conclusion: Hereby, we evaluated the side effects of two different pharmaceutical forms by designing a sustainable and reproducible celiac rat model that can be induced with olmesartan medoxomil.
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    Evaluation of anti-inflammatory, immunomodulatory effects and celiac-like side effect of olmesartan medoxomil as a vitamin D receptor agonist and angiotensin II receptor blocker
    (Journal of Research in Pharmacy, 2022) Karasulu, Ercüment
    Prodrug Olmesartan Medoxomil (OM) is an angiotensin II receptor blocker (ARB) and a vitamin D Receptor (VDR) agonist. Reducing the inflammation and improving the immune system OM prevents organ damage. Angiotensin II receptor blockers (ARBs) can raise serum and tissue levels of the membrane-bound form of monocarboxypeptidase angiotensin converting enzyme 2 (ACE2). Increased ACE2 activity causes the balance in the RAAS to shift towards the positive ACE2-Ang-(1-7). Therefore It can be useful with anti-inflammatory, anti-fibrotic and anti-oxidative stress signals in the treatment of immune system diseases. OM is also known to have adverse effects, such as celiac-like enteropathy which was accepted by the FDA. The mechanism of OM's intestinal injury is thought to be the excessive consumption of the enzymes POX1 and carboxymethylenebutenolidase, which are also responsible for the the digestion of gliadin during the hydrolysis of the drug. Cell-mediated immune response and genetic predisposition are the other factors. Our histopathological findings of olmesartan-induced celiac-like enteropathy in rat intestines were increased mononuclear cell infiltration and villous atrophy. In this study these various action mechanisms of OM and its possible immun system booster effects were discussed. The findings of our rat intestines after exposure to OM-Suspension supported and correlated clinical findings of OM. In conclusion, by making extensive evaluations, OM can be a promising immunomodulator agent in immune system diseases.
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    Permeability of olmesartan medoxomil from lipid based and suspension formulations using an optimized HDM-PAMPA model
    (2022) Komesli, Yelda; Karasulu, Ercüment
    Hexadecane membrane-parallel artificial membrane permeability assay (HDM-PAMPA) is based on an artificial hexadecane membrane that separates the two compartments (donor and acceptor compartment). This model is used to predict the permeability of drugs in gastrointestinal tract and to simulate the passive absorption. In vivo behaviour of the drugs can be estimated with these systems in drug development studies. In our study we optimized HDM-PAMPA model to determine permeability of olmesartan medoxomil (OM) lipid based drug delivery system (OM-LBDDS). In order to prove that LBDDS formulation facilitates the weak permeability of OM, permeation rates were compared with the OM suspension formula (containing 0.25% v/w CMC). The experiment was performed on a 96-well MultiScreen® PAMPA filter plate (MAIPN4510). The permeability of olmesartan formulations from the donor to acceptor compartment separated by a HDM membrane were determined by the previous validated HPLC method. We created positive control series without coating hexadecane membrane to present the LBDDS and suspension formulation permeability from uncoated plates. The effective permeability constant (Pe) was calculated by the formula and improvement of permeability of OM-LBDDS formulation from hexadecane membrane was confirmed. On the contrary there was no permeation of OM-Suspension in the hexadecane coated plates. As a result, the intestinal permeability of OM-LBDDS was calculated to be at least 100 times more than the suspension. OM-Suspension permeation was only observed in the hexadecane uncoated positive control plates. This was also manifestation of HDM-PAMPA mimicking permeability of intestines because of its lipidic construction.
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    Synthesis, molecular modeling, in vivo study and anticancer activity against prostate cancer of (+) (S)-naproxen derivatives
    (Elsevier Masson s.r.l., 2020) Birgül, Kaan; Yıldırım, Yeliz; Karasulu, H.Yeşim; Karasulu, Ercüment; Uba, Abdullah İbrahim; Yelekçi, Kemal; Küçükgüzel, Ş.Güniz; Cumaoğlu, Ahmet; Kabasakal, Levent; Yılmaz, Özgür
    In this study, (S)-naproxen thiosemicarbazides (3a-d), 1,2,4-triazoles (4a-c), triazole-thioether hybride compounds (5a-p) were synthesized and their structures (3a, 3d, 4a and 5a-p) were confirmed by FT-IR, 1H NMR,13C NMR, HR-Mass spectra and elemental analysis. These compounds are designed to inhibit methionine amino peptidase-2 (MetAP2) enzyme in prostate cancer. These compounds (3d, 5a-p) evaluated against androgen-independent prostate adenocarcinoma (PC-3, DU-145) and androgen-dependent prostate adenocarcinoma (LNCaP) cell lines by using MTS method. Compounds 5a, 5b, 5d and 5e showed 14.2, 5.8, 10.8 and 8.4 ?M anticancer activity against PC-3 cell lines, compounds 5e, 5g and 5n presented anticancer activity against DU-145 cell lines 18.8, 12.25 and 10.2 ?M, and compounds 5g, 5m and 5n exhibited anticancer activity against LNCaP cell lines 12.25, 22.76 and 2.21 ?M, respectively. Consequently, of these results, compounds 5e and 5n showed the highest activities against androgen dependent and independent prostate cancer cell lines, so these compounds could be potent small molecules against prostate cancer. Furthermore, mitogen-activated protein kinase (MAPK) pathway activation, AKT (protein kinase B) phosphorylation and androgen receptor activation of compound 5n (SGK636) were investigated in LNCaP cells by using Western blot method. Compound 5n (SGK636) was also tested against mRNA expression analysis of the Bax, Bcl-2, Caspase 3, Caspase 9 by using real-time PCR analysis. Compound 5n was given to nude male mice with cancer in comparison to the control group. Compound 5n was found to reverse the malignant phenotype in the nude male mice, whereas the prostate cancer progressed in the control group. Analysis of some blood parameters in the study showed that they were within the normal values with respect to the control. The blood values of the animals treated according to the control group also exhibited compliance with the blood limit values. Molecular docking and dynamics simulation of compound 5n binding to Methionine Aminopeptidase 2 (MetAP2) enzyme rationalized its potential activity. In addition, inhibition assay MetAP2 enzyme of compound 5n was evaluated. Taken together, we suggest compound 5n to be a potential candidate for prostate cancer therapy. © 2020 Elsevier Masson SAS