Ultra-Facile Fabrication of Hydrogels through Photopolymerization of Oleyl Methacrylate and Epoxidized Oleyl Methacrylate with N-Isopropylacrylamide

This study reports an ultra-facile, economical, and environmentally friendly hydrogel synthesis method using renewable raw materials. The synthesis and photopolymerization of oleyl methacrylate (OM) and the epoxidized derivative of OM monomers are evaluated. In the first step, oleyl alcohol is esterified with methacryloyl chloride and then epoxidized via the Prilezhaev reaction. These monomers are used for hydrogel synthesis. For this purpose, they are polymerized with N-isopropyl acrylamide, N,N-methylene bis(acrylamide), or ethylene glycol dimethacrylate (EDGMA) via the photopolymerization technique. Novel hydrogels are successfully fabricated using a green process. Epoxidized OM-based hydrogel achieves an excellent yield of 87.1%. Moreover, low-energy UV irradiation and short reaction times reduces energy consumption. The thermal properties of the gels are also considered by differential scanning calorimetry (DSC) and thermogravimetric analysis techniques. DSC results reveal that the epoxidized OM-based hydrogel exhibits a melting peak at 84.5 °C. The highest 5% weight loss temperature is obtained for the OM-EDGMA copolymer as an indicator of thermal stability. © 2022 Wiley-VCH GmbH

Effect of Plant Oil-Based Crosslinker on Drug Release Behaviour of Hydrogels

Thermoresponsive hydrogels have great potential in biomedical applications such as drug delivery systems and tissue engineering. Synthesis of hydrogels from renewable resources attracts attention day by day. In this study special type of thermoresponsive hydrogels were synthesized. These hydrogels are cross-linked hydrophilic polymers containing some biocompatible moieties which are derived from plant oils. Renewable resources based biocompatible materials are easily accessible, cost effective and also eco-friendly. This study is focused on synthesis of thermoresponsive hydrogels by using plant oil-based crosslinker. N-Isopropylacrylamide (NIPAM) was used as thermoresponsive monomer and acrylated methyl ricinoleate (AMR) was used as plant oil-based crosslinker. The effect of crosslinker to monomer ratio on polymerization was investigated. Spectrophotometric measurements of quercetin molecule, one of the phenolic flavonoids, were performed at room temperature (RT) and body temperature (37 degrees C). It was found that quercetin molecule released from hydrogels to aqueous medium is higher at body temperature compared to room temperature and also the molar ratio of crosslinker to monomer affects the release behaviour of hydrogels significantly. Finally plant-oil based crosslinker AMR, derived from renewable sources, can be used for hydrogel synthesis instead of other commercial crosslinker

Thermoresponsive hydrogels based on renewable resources

This work aims to synthesize novel thermoresponsive hydrogels from renewable resources, bacterial cellulose (BC), and castor oil (CO), and to investigate the effect of CO on physical and thermal behaviors of BC/Poly(N-isopropylacrylamide) (PNIPAM) hydrogels. The structural properties of the hydrogels are analyzed by Fourier-transform infrared (FTIR) spectroscopy. Differential scanning calorimeter (DSC) technique and thermogravimetric analysis (TGA) are also performed to examine the thermal properties of the hydrogels. The morphological differences of the hydrogels are analyzed by scanning electron microscope (SEM). The thermoresponsive performances of the hydrogels are examined by swelling and deswelling behaviors. The hydrogel with CO is found to be more sensitive to temperature changes than the one without CO. Deswelling study demonstrates 91 and 25% of water loss for hydrogels with and without CO, respectively. The present study shows a novel approach to synthesize thermoresponsive hydrogels with renewable resources for biomedical applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48861. © 2019 Wiley Periodicals, Inc

Edoxaban versus warfarin in patients with atrial fibrillation

Contains fulltext : 125374.pdf (publisher's version ) (Open Access)BACKGROUND: Edoxaban is a direct oral factor Xa inhibitor with proven antithrombotic effects. The long-term efficacy and safety of edoxaban as compared with warfarin in patients with atrial fibrillation is not known. METHODS: We conducted a randomized, double-blind, double-dummy trial comparing two once-daily regimens of edoxaban with warfarin in 21,105 patients with moderate-to-high-risk atrial fibrillation (median follow-up, 2.8 years). The primary efficacy end point was stroke or systemic embolism. Each edoxaban regimen was tested for noninferiority to warfarin during the treatment period. The principal safety end point was major bleeding. RESULTS: The annualized rate of the primary end point during treatment was 1.50% with warfarin (median time in the therapeutic range, 68.4%), as compared with 1.18% with high-dose edoxaban (hazard ratio, 0.79; 97.5% confidence interval [CI], 0.63 to 0.99; P<0.001 for noninferiority) and 1.61% with low-dose edoxaban (hazard ratio, 1.07; 97.5% CI, 0.87 to 1.31; P=0.005 for noninferiority). In the intention-to-treat analysis, there was a trend favoring high-dose edoxaban versus warfarin (hazard ratio, 0.87; 97.5% CI, 0.73 to 1.04; P=0.08) and an unfavorable trend with low-dose edoxaban versus warfarin (hazard ratio, 1.13; 97.5% CI, 0.96 to 1.34; P=0.10). The annualized rate of major bleeding was 3.43% with warfarin versus 2.75% with high-dose edoxaban (hazard ratio, 0.80; 95% CI, 0.71 to 0.91; P<0.001) and 1.61% with low-dose edoxaban (hazard ratio, 0.47; 95% CI, 0.41 to 0.55; P<0.001). The corresponding annualized rates of death from cardiovascular causes were 3.17% versus 2.74% (hazard ratio, 0.86; 95% CI, 0.77 to 0.97; P=0.01), and 2.71% (hazard ratio, 0.85; 95% CI, 0.76 to 0.96; P=0.008), and the corresponding rates of the key secondary end point (a composite of stroke, systemic embolism, or death from cardiovascular causes) were 4.43% versus 3.85% (hazard ratio, 0.87; 95% CI, 0.78 to 0.96; P=0.005), and 4.23% (hazard ratio, 0.95; 95% CI, 0.86 to 1.05; P=0.32). CONCLUSIONS: Both once-daily regimens of edoxaban were noninferior to warfarin with respect to the prevention of stroke or systemic embolism and were associated with significantly lower rates of bleeding and death from cardiovascular causes. (Funded by Daiichi Sankyo Pharma Development; ENGAGE AF-TIMI 48 ClinicalTrials.gov number, NCT00781391.)