Sanjeev Ganesh

Swelling and Diffusion Characteristics of Stimuli-Responsive N-Isopropylacrylamide and κ-Carrageenan Semi-IPN Hydrogels

Semi-IPN formation has been achieved in a system comprising N-isopropylacrylamide and κ-carrageenan by an electron beam irradiation technique. The conditions for obtaining mechanically stable gels have been optimized. The gels were characterized by DSC, SEM, and FTIR techniques. Dynamic swelling measurements were carried out under different pH and temperature conditions. The results revealed the structure, pH, and temperature-dependent swelling behavior of the gels. The % swelling (S) of the hydrogels at various pH followed the order 9.0 < 1.2 <4.0 < 7.0. Also, the gels exhibited temperature dependence, with swelling being highest around 30°C. The “n” values for these hydrogels were in the range 0.31–0.79, indicating that the mechanism of water transport changes from Fickian to anomalous diffusion, with change in the network structure of the gel matrix.

Sustained Release of Metoprolol Tartarate from Radiation-Grafted pH-Responsive Hydrogels

pH-responsive hydrogels composed of methacrylic acid (MAA) grafted on poly(ethylene oxide)-poly(vinylpyrrolidone)(PEO-PVP) network were made by electron beam irradiation technique. The grafting was carried out at various concentrations of MAA with different irradiation doses. The gels were characterized by IR, DSC and SEM techniques. The swelling behavior of the gels was studied under different pH conditions. The swelling parameters were evaluated. The mode of water diffusion into the gels was found to be structure-dependent. The pH responsiveness of the gels was evident from the enhanced swelling of the gels with increasing pH of the medium. The suitability of these gels as matrix materials for stimuli-responsive sustained-release drug formulations was studied. The in vitro release profile of an antihypertensive drug, metoprolol tartarate, from these gels was studied at pH 1.2 and 7.4. The extent of drug release is found to be pH-dependent. The data were analyzed to understand the mechanism of drug release from the gels. The gels exhibited diffusion-controlled release behavior. Drug release kinetic analysis indicated “first order” release where the amount of drug released is dependent on the matrix drug load and the value of the diffusion coefficient indicated anomalous diffusion.

Effect of electron beam irradiation on the structure and optical properties of nickel oxide nanocubes

This work reports the effect of electron beam (EB) irradiation on the structure and optical properties of nanocrystalline nickel oxide (NiO) cubes. NiO nanocubes were synthesized by the chemical precipitation method. The characterization was carried out by employing analytical techniques like X-ray diffraction, transmission electron microscopy, UV–visible and photoluminescence (PL) spectroscopy. The present investigation found that non-stoichiometry, defects and particle size variation caused by EB irradiation have a great influence on optical band gap, blue shift and band modification of absorption and PL spectra. Moreover, EB irradiation can result enhanced optical absorption performance and photo-activity in NiO nanocubes for optoelectronics and photo-catalytic applications. The study of International Commission on Illumination chromaticity diagram indicates that NiO can be developed as a suitable phosphor material for the application in near ultraviolet excited colour LEDs.

In-Vitro Release Study of Metoprolol Succinate from the Bioadhesive Films of Pullulan-Polyacrylamide Blends

In the present work, an attempt has been made to investigate the drug release profile of pullulan-polyacrylamide blend films with metoprolol succinate as a model drug. The drug diffusion behavior of pullulan/polyacrylamide films has been established by an open glass diffusion cell at 37 ± 1°C. The diffusion rate of the drug was determined by UV/visible spectroscopy. The kinetics of drug release are fitted to the Higuchi and Koresmeyer–Peppas model. The drug release kinetics for the blend was found to be fast and follows Fickian mechanism. This blend could be a promising approach for formulating a transdermal drug delivery system for immediate release with good film-forming property.

Influence of electron beam irradiation on structural and optical properties of α-Ag2WO4 nanoparticles

The influence of 8MeV electron beam irradiation on the structural and optical properties of silver tungstate (α-Ag2WO4) nanoparticles synthesized by chemical precipitation method was investigated. The dose dependent effect of electron irradiation was investigated by various characterization techniques such as, X-ray diffraction, scanning electron microscopy, UV-vis absorption spectroscopy, photoluminescence and Raman spectroscopy. Systematic studies confirm that electron beam irradiation induces non-stoichiometry, defects and particle size variation on α-Ag2WO4, which in turn results changes in optical band gap, photoluminescence spectra and Raman bands.

Swelling and Metal Ion Adsorption Characteristics of Radiation Synthesized Stimuli Responsive PAAm-KC Semi – IPN Hydrogels

The preparation of super absorbent hydrogels based on Kappa-carrageenan and polyacrylamide was carried out by electron beam irradiation technique. The gels were characterized for their temperature and pH responsive behavior by equilibrium swelling experiments and for their structure by FTIR, DSC, and SEM techniques. The effect of polymer composition, dose applied, pH, and temperature on swelling was evaluated. The suitability of these systems as matrix materials for the uptake of Cu2+ and Ni2+ ions from aqueous solutions was studied. The influence of gel structure and pH conditions on metal ion uptake capacity of gels were investigated. The metal ion uptake capacity has been correlated with the swelling ability of the gels.

Sustained Release of Atorvastatin from Radiation-Synthesized Stimuli-Responsive Hydrogels

The present paper deals with the study of suitability of interpenetrating network hydrogels comprising N-isopropylacrylamide and k-carrageenan as matrix materials for the sustained release of Atorvastatin. The drug was incorporated in various gels by the active-loading technique and the in-vitro release kinetics was studied at pH 1.2 and 7.4. When the release data were analyzed as per the Korsmeyer and Peppas equation, the release exponent “n” was observed to be dependent on temperature and pH conditions, indicating the influence of release conditions on gel structure and in turn on the drug release mechanism.

Miscibility and Thermal Behavior of Pullulan/Polyacrylamide Blends

Blends of Pullulan (PU) and Polyacrylamide (PAM) having biomedical applications were prepared and characterized in order to evaluate the miscibility of natural component with the synthetic one. Blends with different composition ratios were prepared using water as common solvent. Viscosity, ultrasonic velocity and density were measured at 30 and 40°C. Furthermore, the blend films were prepared by a solution casting method and analyzed by DSC, FTIR and TGA methods. Results of ultrasonic and density methods revealed the semi-miscibility of the blend. Using viscosity data, interaction parameters (Chees ‘μ’ and Suns ‘α’) were computed. The values confirmed that the blend is miscible when the Pullulan content is less than 20% in the blend. Change in temperature had no effect on the miscibility nature of the blends. Intermolecular interactions of hydrogen bonding type were confirmed by DSC and FTIR methods. Thermal behavior of blends was investigated using TGA method.