排序方式: 共有163条查询结果,搜索用时 15 毫秒
71.
Sayyed A. Sajadi Tabassi Farnaz Sadat Mirzazadeh Tekie Farzin Hadizadeh Rahof Rashid Elham Khodaverdi Seyed Ahmad Mohajeri 《Journal of Sol-Gel Science and Technology》2014,69(1):166-171
Supramolecular hydrogels (SMGel) have attracted much attention as a drug and gene delivery system in recent years. In this study, SMGels based on the tri-block copolymer of poly-ε-caprolactone–polyethylene glycol–poly-ε-caprolactone (PCL–PEG–PCL) and α-cyclodextrin (α-CD) were prepared and evaluated for the delivery of two model drugs, naltrexone hydrochloride and vitamin B12. Tri-block copolymers were synthesized easily in 15 min by ring-opening polymerization using the microwave irradiation technique, and their structures were determined by gel permeation chromatography and nuclear magnetic resonance methods. SMGels composed of various concentrations of the copolymer and α-CD were prepared and characterized for their rheological behaviour, their gel formation time and in vitro drug release profile. The results indicated that copolymers with a PCL to PEG ratio of 1:4 are suitable for SMGel preparation. The most viscose system with good syringeability was prepared by mixing 12 % wt α-CD and 10 % wt of copolymer. The gelation was found to occur within a minute after mixing. The viscosity of the hydrogel systems was determined as a function of shear rate. Finally, in vitro B12 release through the hydrogel systems was studied. Up to 80 % of Vitamin B12 was released through this system during a period of 20 days. Rheological evaluation revealed that the hydrogel has shear thinning properties, and the system regained its ground rheological state in a time dependent manner. Polymer concentration did not affect the drug release profiles. Finally, it was concluded that such systems are appropriate drug delivery systems due to their ability to provide a controlled drug release profile and their shear thinning thixotropic behaviour, which makes them syringeable and injectable. 相似文献
72.
Malek T. Maghsoodlou Nourollah Hazeri Sayyed M. Habibi‐Khorasani Ghasem Marandi Mahmoud Nassiri 《合成通讯》2013,43(21):2771-2777
The highly reactive 1∶1 intermediate produced in the reaction of aryl isocyanides and acetylenic esters was trapped by the α‐dicarbonyl compounds to yield γ‐spiroiminolactone derivatives in good yields. 相似文献
73.
A clay catalyzed synthesis of 2-(2',2',2'-trichloro)ethylidene-3-oxo-3-(2''-chlorophenyl)propionate (2) and its application for the preparation of various N-alkyl-1,4-dihydro-4-oxo-3-quinolinecarboxylic acids (5a-e) has been described. 相似文献
74.
Malek T. Maghsoodlou Nourollah Hazeri Sayyed M. Habibi‐Khorasani Reza Heydari Ghasem Marandi Mahmoud Nassiri 《合成通讯》2013,43(19):2569-2574
The reactive 1∶1 intermediate generated by the addition of alkyl and aryl isocyanides to dialkyl acetylenedicarboxylate was trapped by 2,7‐dinitrofloren‐9‐one and floren‐9‐one to yield iminolactones in good yields. 相似文献
75.
Mohsen Rostamizadeh Malek Taher Maghsoodlou Nourallah Hazeri Sayyed Mostafa Habibi-khorassani Leila Keishams 《Phosphorus, sulfur, and silicon and the related elements》2013,188(2):334-337
Abstract For the first time, α-aminophosphonates were obtained by a simple and efficient one-pot method from the reaction between aldehyde, aniline, and triphenyl phosphite in the presence of acetic acid as a catalyst and solvent at room temperature. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT 相似文献
76.
Sayyed Hossein Hashemi Morteza Ziyaadini Massoud Kaykhaii Ahmad Jamali Keikha Nasrin Naruie 《Journal of separation science》2020,43(2):505-513
By synthesizing a molecular imprinted polymer as an efficient adsorbent, ciprofloxacin was micro‐extracted from seawater, human blood plasma and tablet samples by pipette‐tip micro solid phase extraction and determined spectrophotometrically. Response surface methodology was applied with central composite design to build a model based on factors affecting on microextraction of ciprofloxacin; including volume of eluent solvent, number of extraction cycles, number of elution cycles, and pH of sample. Other factors that affect extraction efficiency, such as type of eluent solvent, volume of sample, type, and amount of salt were optimized with one‐variable‐at‐a‐time method. Under optimum extraction condition, pH of sample solution was 7.0, volume of eluent solvent (methanol) was 200 µL, volume of sample solution was 10 mL, and the number of extraction and elution cycles was five and seven, respectively, amount of Na2SO4 (as salt) and MIP (as sorbent) were optimized at 150 and 2 mg, respectively. The linear range of the suggested method under optimum extraction factors was 5–150 µg/L with a limit of detection of 1.50 µg/L for the analyte. Reproducibility of the method (as relative standard deviation) was better than 7%. 相似文献
77.
Ghanwat A. A. Sayyed M. M. Wadgaonkar P. P. Maldar N. N. 《Journal of Thermal Analysis and Calorimetry》2009,98(2):539-545
Journal of Thermal Analysis and Calorimetry - Aromatic polyamides find many applications in diverse and critical areas due to their high thermal stability coupled with high mechanical properties.... 相似文献
78.
Ta VT Nimse SB Song KS Kim J Sayyed DR Nguyen VT Kim T 《Chemical communications (Cambridge, England)》2011,47(40):11261-11263
The mixed SAM obtained by the self-assembly of the monothiolated calix[4]crown-5 receptor 1 and the subsequent addition of the thiolated alkylferrocene guest 3 was characterized at the molecular scale by the favorable receptor-guest interactions by using cyclic voltammetry (CV). 相似文献
79.
The physisorption of methane in homogeneous armchair open-ended SWCNT triangular arrays for the tubes of diameter of 10.85, 13.57, 16.28 and 19.00 Å [(8,8), (10,10), (12,12) and (14,14), respectively] at temperature of 273, 298, 323 and 373 K and at fugacity of 0.5–9.0 Mpa is evaluated by means of Grand Canonical ensemble Monte Carlo simulation. The applied intermolecular forces are modeled using Lennard-Jones potential model. The absolute, excess and delivery adsorption isotherms of methane in various carbon nanotube arrays are calculated. Besides, specific surface areas and the isosteric heats of adsorption, Q st, are studied, also different isotherm models were fitted on the simulation adsorption data, and the model parameters are correlated. A novel geometrical relationship is introduced to calculate accessible interstitial and intratubular volumes. According to our simulation results, one can reaches to 96% of the US Department of Energy target for CH4 storage of 180 v/v at 298 K and 35 bar by using the SWCNT array with nanotube’s diameter of 19 Å as adsorbent. For intertube distance equal 3.4 Å, no gas adsorption is observed in interstitial channel except for the arrays bigger than 15.4 Å in nanotube’s diameter, and multi-layer adsorption starts to form in nanotube’s diameter of 16.28 Å at the pressure of 2.0 MPa. 相似文献