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Reddy, P. Rama Subba,Eswaramma, S.,Krishna Rao, K.S.V.,Lee, Yong Ill Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.8
Novel dual responsive pectin hydrogels composed from poly(acrylamidoglycolic acid-co-vinylcaprolactam)/Pectin (PAV-PC) and also PAV-PC hydrogels are used as templates for the production of silver nanoparticles. 5-Fluorouracil is an anticancer drug and has been loaded in situ into PAV-PC hydrogels. Structure and morphology characterization of PAV-PC hydrogels were investigated by fourier transform infrared spectroscopy, differential scanning calorimetry, thermo gravimetric analysis, X-ray diffraction studies, scanning electron microscopy and transmission electron microscopy. The results revealed a molecular level dispersion of the drug in PAV-PC hydrogels. In vitro release of 5-fluorouracil from the PAV-PC hydrogels has been carried out in GIT fluids as well as in various temperatures. 5-Fluorouracil released from PAV-PC hydrogels was 50% at pH 1.2, and 85% at pH 7.4 within 24 h. The release profile was characterized with PAV-PC hydrogels and initial burst effect was significantly reduced in two buffer media (1.2 and 7.4), followed by a continuous and controlled release phase, the drug release mechanism from polymer was due to Fickian diffusion. In situ fabrication of silver nanoparticles inside the hydrogel network via the reduction of sodium borohydrate by PAV-PC chains led to hydrogel nanocomposites. The diameter of the nanocomposites was about 50-100 nm, suitable for uptake within the gastrointestinal tract due to their nanosize range and mucoadhesive properties. These nanocomposite PAV-PC hydrogels showed strong antimicrobial activity towards Bacillus subtilis (G+ve) and Escherichia coli (G-ve).
Reddy, Lakshmi C. Narayana,Reddy, Rama Subba P.,Rao, Krishna K.S.V.,Subha, M.C.S.,Rao, Chowdoji K. Korean Chemical Society 2013 대한화학회지 Vol.57 No.4
Chitosan (CS) and hydroxypropylmethyl cellulose (HPMC) blend microspheres were prepared by water-in-oil emulsion technique and were loaded with an anti-cancer drug 5-fluorouracil (5-FU). CS-HPMC microspheres were characterized by Fourier transform infrared spectroscopy to confirm the cross-linking reaction. Scanning electron microscopy (SEM) was also used to assess the surface morphology of particles prepared. The quantity of release of 5-FU from the microspheres have been studied in terms of blend composition and amount of cross-linking agent. Differential scanning calorimetry and X-ray diffraction techniques indicated a uniform distribution of 5-FU particles in microspheres, whereas SEM suggested the spherical structure of the microspheres with slight rough surface. The in vitro drug release indicated that the particle size and release kinetics depend upon blend composition, amount of cross-linking agent used and amount of 5-FU present in the microspheres.
P. Rama Subba Reddy,S. Eswaramma,K. S. V. Krishna Rao,이용일 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.8
Novel dual responsive pectin hydrogels composed from poly(acrylamidoglycolic acid-co-vinylcaprolactam)/ Pectin (PAV-PC) and also PAV-PC hydrogels are used as templates for the production of silver nanoparticles. 5-Fluorouracil is an anticancer drug and has been loaded in situ into PAV-PC hydrogels. Structure and morphology characterization of PAV-PC hydrogels were investigated by fourier transform infrared spectroscopy, differential scanning calorimetry, thermo gravimetric analysis, X-ray diffraction studies, scanning electron microscopy and transmission electron microscopy. The results revealed a molecular level dispersion of the drug in PAV-PC hydrogels. In vitro release of 5-fluorouracil from the PAV-PC hydrogels has been carried out in GIT fluids as well as in various temperatures. 5-Fluorouracil released from PAV-PC hydrogels was 50% at pH 1.2, and 85% at pH 7.4 within 24 h. The release profile was characterized with PAV-PC hydrogels and initial burst effect was significantly reduced in two buffer media (1.2 and 7.4), followed by a continuous and controlled release phase, the drug release mechanism from polymer was due to Fickian diffusion. In situ fabrication of silver nanoparticles inside the hydrogel network via the reduction of sodium borohydrate by PAV-PC chains led to hydrogel nanocomposites. The diameter of the nanocomposites was about 50-100 nm, suitable for uptake within the gastrointestinal tract due to their nanosize range and mucoadhesive properties. These nanocomposite PAV-PC hydrogels showed strong antimicrobial activity towards Bacillus subtilis (G+ve) and Escherichia coli (G-ve).
Synthesis of Alginate Based Silver Nanocomposite Hydrogels for Biomedical Applications
P. Rama Subba Reddy,하창식,K. Madhusudana Rao,K. S. V. Krishna Rao,Yury Shchipunov 한국고분자학회 2014 Macromolecular Research Vol.22 No.8
Sodium alginate and poly(acrylamide-co-N-vinylcaprolactam-co-acrylamidoglycolic acid) based dualresponsive semi-IPN hydrogels (SA-PAVA) were successfully synthesized by free radical redox polymerization. N,N'-Methylene-bis-acrylamide was used as a crosslinker and 5-fluorouracil, an anti-cancer drug, was loaded ontothese semi-IPN hydrogels via equilibrium swelling method. The hydrogels were also used as templates for the productionof silver nanoparticles by using NaBH4 as reducing agent. In order to understand the polymer-drug interactions,pristine, as well as drug loaded, SA-PAVA hydrogels were characterized by Fourier transform infrared spectroscopyand differential scanning calorimetry. The formation of silver nanoparticles was confirmed by UV-visible spectroscopy,thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy(TEM). The swelling behavior of the hydrogel was investigated in distilled water under various pH and temperatureconditions. In vitro release of 5-fluorouracil from these SA-PAVA hydrogels was carried out in gastro-intestinal fluidsdifferent temperatures. The SA-PAVA hydrogel/silver nanocomposites showed excellent anti-bacterial activitytowards Escherichia coli and Bacilli.
B. Lakshmi,Krishna Reddy K. Rama,Gouda Avaji Prakash,K. N. Shivananda,K. N. Mahendra 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.5
A hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) containing Co(II), Ni(II) and Cu(II) ions was prepared by curing N-MPGE and tetradentate Schiff base Co(II),Ni(II) and Cu(II) complexes. The curing polymerization reaction of N-MPGE with metal complexes as curing agents was studied. The cured samples were studied for thermal stability, chemical (acid/alkali/solvent) and water absorption resistance and homogeneity of the cured systems. The tetradentate Schiff base, 3-[(Z)-2-piperazin-1-yl-ethylimino]-1,3-dihydro indol-2-one was synthesized by the condensation of Isatin (Indole-2, 3-dione) with 1-(2-aminoethyl)piperazine (AEP). Its complexes with Co(II), Ni(II) and Cu(II) have been synthesized and characterized by microanalysis, conductivity, Uv-Visible, FT-IR, TGA and magnetic susceptibility measurements. The spectral data revealed that the ligand acts as a neutral tetradentate Schiff base and coordinating through the azomethine nitrogen, two piperazine nitrogen atoms and carbonyl oxygen
Lakshmi, B.,Shivananda, K.N.,Prakash, Gouda Avaji,Rama, Krishna Reddy K.,Mahendra, K.N. Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.5
A hybrid thermosetting maleimido epoxy compound 4-(N-maleimidophenyl) glycidylether (N-MPGE) containing Co(II), Ni(II) and Cu(II) ions was prepared by curing N-MPGE and tetradentate Schiff base Co(II), Ni(II) and Cu(II) complexes. The curing polymerization reaction of N-MPGE with metal complexes as curing agents was studied. The cured samples were studied for thermal stability, chemical (acid/alkali/solvent) and water absorption resistance and homogeneity of the cured systems. The tetradentate Schiff base, 3-[(Z)-2-piperazin-1-yl-ethylimino]-1,3-dihydro indol-2-one was synthesized by the condensation of Isatin (Indole-2, 3-dione) with 1-(2-aminoethyl)piperazine (AEP). Its complexes with Co(II), Ni(II) and Cu(II) have been synthesized and characterized by microanalysis, conductivity, Uv-Visible, FT-IR, TGA and magnetic susceptibility measurements. The spectral data revealed that the ligand acts as a neutral tetradentate Schiff base and coordinating through the azomethine nitrogen, two piperazine nitrogen atoms and carbonyl oxygen.
B. Vikram Babu,M. Sushma Reddi,A. Rama Krishna,B. Sathish Mohan,G. Chandana,K. Anjani Devi,B. Sridhar,K. Samatha 한국전기전자재료학회 2022 Transactions on Electrical and Electronic Material Vol.23 No.5
This research article aims at reporting the influence of magnesium by studying the structural, electrical impedance and modulus properties of the Mg substituted Li 4 Ti 5 O 12 . These studies are useful for the electrochemical properties. The XRD reveals that the structure of all the Mg substituted materials belongs to the cubic spinel group having Fd-3m space symmetry. SEM images display the structural, morphological properties with the average size of grains falling in the vicinity of 1 μm. The electrical impedance of Li 4− x Mg x Ti 5 O 12 materials was analyzed at frequencies between 20 Hz and 1 MHz and in the 30–120 °C range of temperature by employing the complex impedance spectroscopy (CIS) method. The modulus formalism is also a suitable tool to understand the dynamical characteristics of electrical transport phenomena. The complex electric modulus spectrum signifi es quantifying the allocation of ion energies or confi gurations in the lattice. Also, it portrays the electrical relaxation of ion-conducting lattices as a feature of materials at a minuscule level. The obtained results of substitution of Mg in Li 4 Ti 5 O 12 anode materials improve the potential applications of conductivity and charge/discharge performance.