Anil Kumar Bajpai

Real time in vitro studies of doxorubicin release from PHEMA nanoparticles

BackgroundMany anticancer agents have poor water solubility and therefore the development of novel delivery systems for such molecules has received significant attention. Nanocarriers show great potential in delivering therapeutic agents into the targeted organs or cells and have recently emerged as a promising approach to cancer treatments. The aim of this study was to prepare and use poly-2-hydroxyethyl methacrylate (PHEMA) nanoparticles for the controlled release of the anticancer drug doxorubicin.ResultsPHEMA nanoparticles have been synthesized and characterized using FTIR and scanning electron microscopy (SEM), particle size analysis and surface charge measurements. We also studied the effects of various parameters such as percent loading of drugs, chemical architecture of the nanocarriers, pH, temperature and nature of the release media on the release profiles of the drug. The chemical stability of doxorubicin in PBS was assessed at a range of pH.ConclusionSuspension polymerization of 2-hydroxyethyl methacrylate (HEMA) results in the formation of swellable nanoparticles of defined composition. PHEMA nanoparticles can potentially be used for the controlled release of the anticancer drug doxorubicin.

Controlled pesticide release from biodegradable polymers

Polymers have been widely used in agriculture for applications including controlled release of pesticides and other active ingredients. The ability to predict their delivery helps avoid environmental hazards. Macromolecular matrices used as carriers in controlled release of agricultural active agents, especially pesticides, are reviewed. The review focuses on the advantages and mechanisms of controlled release. It includes biodegradable polymers in agriculture, their manufacturing methods, and their degradation mechanisms and kinetics. The article also presents a critical account of recent release studies and considers upcoming challenges.

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.

Evaluation of poly (vinyl alcohol) based cryogel–zinc oxide nanocomposites for possible applications as wound dressing materials

In this investigation cryogels composed of poly (vinyl alcohol) (PVA) were prepared by repeated freeze thaw method followed by in situ precipitation of zinc oxide nanoparticles within the cryogel networks. Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX) were used to characterize the nanocomposites. The morphologies of native PVA cryogels and PVA cryogel-ZnO nanocomposites were observed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) techniques. The SEM analysis suggested that cryogels show a well-defined porous morphology whereas TEM micrographs revealed the presence of nearly spherical and well separated zinc oxide nanoparticles with diameter<100nm. XRD results showed all relevant Braggs reflections for crystal structure of zinc oxide nanoparticles. Thermo gravimetric-differential thermal analysis (TG-DTA) was conducted to evaluate thermal stability of the nanocomposites. Mechanical properties of nanocomposites were determined in terms of tensile strength and percent elongation. Biocompatible nature was ascertained by anti-haemolytic activity, bovine serum albumin (blood protein) adsorption and in vitro cytotoxicity tests. The prepared nanocomposites were also investigated for swelling and deswelling behaviours. The results revealed that both the swelling and deswelling process depend on the chemical composition of the nanocomposites, number of freeze-thaw cycles, pH and temperature of the swelling medium. The developed biocompatible PVA cryogel-ZnO nanocomposites were also tested for antibacterial activities against both Gram-negative and Gram-positive bacteria.

Adsorption of Hg(II) Ions onto Binary Biopolymeric Beads of Carboxymethyl Cellulose and Alginate

The removal of Hg(II) ions from aqueous solution by adsorption onto cross-linked polymeric beads of carboxymethyl cellulose (CMC) and sodium alginate was studied at fixed pH (6) and room temperature 28 ± 0.2°C. The cross-linked polymeric beads were characterized by FTIR spectra. Sorption capacity of the polymer for the mercury ions was investigated in aqueous media consisting different amounts of mercury ions (2.5 to 100 mg dm−3) and at different pH values (2 to 8). Adsorption behavior of Hg(II) ions could be modeled using both the Langmuir and Freundlich isotherms. The dynamic nature of adsorption was quantified in terms of several kinetic constants such as rate constants for adsorption (k1) and Lagergreen rate constant (Kad). The influence of various experimental parameters such as effect of pH, contact time, solid-to-liquid ratio, salt effect, and temperature effect etc. were investigated on the adsorption of Hg(II) ions.

Designing polyethylene glycol (PEG) – plasticized membranes of poly(vinyl alcohol-g-methyl methacrylate) and investigation of water sorption and blood compatibility behaviors

Polyethylene glycol (PEG)-based semi-IPNs have been widely used as hydrogel matrices in tissue engineering applications because of their inherent hydrophilicity and biocompatibility. Today, synthetic scaffolds are being widely used in tissue engineering and allied applications because they offer the ability to precisely control the mechanical properties, morphology, and blood compatibility of the materials. In this regard, an attempt has been made to develop scaffolds membranes by judiciously combining PEG, polyvinyl alcohol, and polymethyl methacrylate. The so prepared hydrogel membranes were undertaken for structural, morphological, and thermal characterization using FTIR, scanning electron microscope (SEM), and DSC techniques, respectively. The hydrogel films were investigated for water sorption capacity under various experimental conditions such as changing chemical composition of the membrane, different pH, and temperature of the swelling media and varying simulated biological fluids. The hydrogel membranes were also studied for their catholicity and in vitro blood compatibility property by following several tests such as blood clot formation, percent haemolysis, and protein adsorption.

Dynamic and Equilibrium Studies on Adsorption of Cu(II) Ions onto Biopolymeric Cross-Linked Pectin and Alginate Beads

Binary biopolymeric beads of alginate and pectin were prepared and characterized by FTIR spectra. On to the surfaces of the prepared beads were performed static and dynamic adsorption studies of Cu(II) ions at fixed pH and ionic strength of the aqueous metal ion solutions. The adsorption data were applied to Langmuir and Freundlich isotherm equations and various adsorption parameters were calculated. The influence of various experimental parameters such as effect of time, pH, temperature, solid to liquid ratio, and the presence of salts were investigated on the adsorption of copper ions.

Removal of Cobalt Ions from Aqueous Solution by Adsorption onto Cross-Linked Calcium Alginate Beads

The removal of cobalt ions from dilute aqueous solutions using cross linked calcium alginate beads as the adsorbent is reported in this article. The influence of various experimental parameters such as pH, initial metal ion concentration, contact time and solid to liquid ratio were studied. The adsorption data were applied to Langmuir and Freundlich isotherm equations and various static parameters were calculated. It was observed that the uptake of cobalt ions was found to increase with time and that maximum adsorption was obtained within the first 60 minutes of the process. These results indicate that the cross linked calcium alginate beads have potential for removing cobalt ions from industrial waste water.

Removal of Chromium(VI) Ions by Adsorption onto Binary Biopolymeric Beads of Sodium Alginate and Carboxymethyl Cellulose

The removal of chromium ions from dilute aqueous solution using biopolymeric beads of cross-linked sodium alginate and carboxymethyl cellulose as the adsorbent is reported in this article. The biopolymeric alginate and carboxymethyl cellulose beads were prepared and characterized by FTIR spectra. On the surface of the prepared beads were performed static and dynamic adsorption studies of chromium ions at fixed pH and ionic strength of the aqueous metal ion solution. The adsorption data were applied to Langmuir and Freundlich isotherm equation and various static parameters were calculated. The dynamic nature of adsorption was quantified in terms of several kinetic constants such as rate constant for adsorption (k1) and Lagergreen rate constant (kad). The influence of various experimental parameters such as pH, time, temperature, solid–liquid ratio, presence of salt, and chemical composition of beads were investigated on the adsorption of chromium ions.

Fabrication of Interpenetrating Networks of Poly (vinyl alcohol-g-acrylamide) and Chitosan-g-polyacrylamide Chains and Evaluation of Water Sorption, Blood Compatibility and Cytotoxicity Behaviors

In the present study an interpenetrating polymer network (IPN) of poly (vinyl alcohol-g-acrylamide) and chitosan-g-polyacrylamide chains were prepared by the redox polymerization method. The prepared network was characterized by FTIR, DSC and ESEM techniques. The hydrogels were evaluated for their water intake potential and influence of various factors such as chemical composition of the hydrogels, pH and temperature of the swelling bath; various simulated biological fluids were investigated on the water sorption capacity of the IPNs. The in-vitro blood compatibility of the prepared IPN was judged by blood-clot formation, percent haemolysis, protein (BSA) adsorption, and cytotoxicity methods.