Sandeep Shukla

Water sorption through a semi-interpenetrating polymer network (IPN) with hydrophilic and hydrophobic chains

Abstract Dynamics of water uptake by semi-interpenetrating polymer networks (IPNs) of poly(acrylamide-co-styrene) and poly(vinyl alcohol) were investigated at room temperature (27±0.2°C) and constant pH. The nature of the swelling process of the IPN was investigated in light of the Fickian transport and the effects of varying experimental conditions such as the change in the composition of the IPN, pH and ionic strength of the swelling medium were studied on the swelling kinetics of the IPN. The networks obtained were also characterized by IR spectral analysis and the molecular weight between crosslinks ( M c ) and crosslink density ( q ) of the networks were evaluated.

Release dynamics of tetracycline from a loaded semi-interpenetrating polymeric material of polyvinyl alcohol and poly(acrylamide-co-styrene)

A semi-interpenetrating polymer network (IPN) of polyvinyl alcohol (PVA) and poly(acrylamide-co-styrene) (PAMS) was prepared and its potential for controlled release of tetracycline was assessed. The IPN was characterized by IR spectral analysis and network parameters such as the average molecular weight between crosslinks (M_c), crosslink density (q) and number of elastically effective chains (V_e) were evaluated. The influence of various experimental conditions such as different percent loadings, composition of the IPNs, thickness of the loaded device, pH and nature of the release medium were investigated on the release profiles of the drug. Various kinetic constants such as the diffusional exponent (n), diffusion constant (D) and penetration velocity (v) were evaluated for different release processes and based on the dynamic release data, an analysis of transport mechanisms of tetracycline was made using Ficks equations.

Swelling Controlled Delivery of Antibiotic from a Hydrophilic Macromolecular Matrix with Hydrophobic Moieties

A hydrophilic macromolecular network containing hydrophobic moieties has been prepared by free radical copolymerization of acrylamide and styrene in the presence of poly(vinyl alcohol) (PVA) and its potential as controlled drug delivery carrier was evaluated with tetracycline as a model antibiotic drug. The amount of drug was assayed spectrophotometrically. The network was characterized by optical microscopy, infra-red spectroscopy and structural parameters such as average molecular weight between crosslinks (Mc), crosslink density (q) and number of elastically effective chains (Ve) were evaluated. It was found that with increasing concentration of PVA, ST and MBA in the hydrogel, the release rate initially increases but after definite concentrations of the above components the release rate falls. In the case of AM, release rate constantly decreases with increasing AM concentration in the hydrogel.

Modulation in sorption dynamics of a pH-sensitive interpenetrating polymer network (IPN)

Abstract The water sorption dynamics of a binary interpenetrating polymer network (IPN) composed of polyvinyl alcohol (PVA) and poly(acrylamide‐co‐acrylic acid) was studied gravimetrically. The IPN was characterized by IR spectral analysis and various network parameters such as molecular weight between crosslinks (M c), crosslink density (q) and number of elastically effective chains (V e) were also evaluated. The effects of various parameters such as composition of the IPN, pH, and temperature of the swelling medium and addition of inorganic salts were investigated on the kinetics of the swelling process. The dynamic swelling parameters such as the swelling exponent, diffusion constants and penetration velocity were evaluated and the possible mechanisms of water sorption were evolved on the basis of the swelling exponent (n), diffusion constant (D), and penetration velocity (v). The enthalpy of mixing of the IPN and the solvent (water) was also calculated using the Gibbs–Helmholtz equation.

MODULATION OF IN VITRO RELEASE OF CRYSTAL VIOLET FROM A BINARY POLYMER HYDROGEL SYSTEM

ABSTRACT A macromolecular vehicle entrapping crystal violet (CV) as a model drug was developed by crosslink polymerization of acrylamide and styrene in the presence of a hydrophilic polymer poly(vinyl alcohol). The loaded polymer matrix was monitored for the controlled release of the crystal violet by a spectrophotometric method. The dynamics of the release process was investigated as a function of the composition of the gel and pH of the release medium. The mechanism of the release process was examined kinetically in terms of the quantitative parameters such as the diffusional exponent n and diffusion constant D evaluated using the Ficks equations.

Studies on Mechanical and Antithrombogenic Behaviors of Polyvinyl Alcohol and Gelatin Based Novel Binary Polymer Blends with Grafted Polyacrylamide Chains

The aim of this study was to design a hydrophilic but mechanically strong macromolecular matrix to discover possible application as polymer scaffolds for tissue engineering and wound healing dressings. To achieve the objectives, acrylamide was polymerized by a redox couple in the immediate presence of polyvinyl alcohol, gelatin and a crosslinking agent (N, N′–methylene bis acrylamide). The structural and thermal characterization of the prepared hydrogels were carried out by Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) which confirmed the formation of polyacrylamide grafted network and presented combined thermal features of the constituent polymers in their thermogram. The Environmental Scanning Electron Microscopy (ESEM) techniques were utilized for morphological characterization and the hydrogels were found to exhibit a highly porous structure. The hydrogels were also investigated for water sorption capacity and the extent of water intake was found to depend on the chemical composition of the gel. The blend hydrogels were also tested for their tensile strength and it was found that for a definite composition of the constituents of the gel the hydrogel offered optimum mechanical properties like tensile strength, percent elongation and Youngs modulus. Thus, the intended objectives to design mechanically strong and blood compatible hydrogels were achieved.