N. Sivagangi Reddy

Synthesis, characterization, and metal uptake capacity of a new polyaniline and poly(acrylic acid) grafted sodium alginate/gelatin adsorbent

AbstractThe present work reports the development of new (sodium alginate-gelatin (SAG))-g-poly(acrylic acid)/polyaniline (SAPAPN) from sodium alginate/gelatin blend by cross-linking with glutaraldehyde, followed by grafting with poly(acrylic acid) and polyaniline by free radical polymerization using ammonium persulfate. The structure, thermal stability, and morphology of SAPAPN adsorbent was characterized by Fourier transform infrared spectroscopy, thermo gravimetric analysis, and scanning electron microscopy, and results were consistent with the expected structures. The influence of various experimental conditions like pH, time, and initial feed concentrations on the uptake of metal ions like Cu2+, Ni2+ by SAPAPN adsorbent was tested. It was seen that the adsorption equilibrium data could be fitted to the Langmuir isotherm. Desorption studies were performed in acid media and EDTA, to examine whether the SAPAPN adsorbent can be recycled for the metal ion removal. The results showed that with SAPAPN adsorb...

Phosphate crosslinked pectin based dual responsive hydrogel networks and nanocomposites: Development, swelling dynamics and drug release characteristics

Potential dual responsive hydrogel networks (PPAD) are fabricated from pectin, poly((2-dimethylamino)ethyl methacrylate)) and phosphate crosslinker bis[2-methacryloyloxy] ethyl phosphate (BMEP) by a simple free radical polymerization. These hydrogel networks are successfully utilized for encapsulation of an anti-cancer drug, 5-fluorouracil (5-FU) and also employed as versatile platforms for production of silver nanoparticles. Fabricated hydrogel networks and silver nanocomposites were characterized by FTIR, SEM, EDX, TEM, DLS, DSC, TGA and XRD. Different polymer network parameters such as MC¯, χ, ξ and υe and diffusion constant (D) were evaluated to assess the drug release profile. The 5FU loaded PPAD hydrogels were used to perform in vitro release studies in both gastric and intestinal conditions of GIT (pH 1.2 & pH 7.4) at two different temperatures (25 and 37°C). On the other hand various kinetic models (zero, first, Higuchi & Koresmeyer-Peppas) have also been employed to fit drug release profile. In addition, the antibacterial activity of PPAD silver nanocomposites were tested against four bacterial species Escherichia coli (-ve), Klebsiella pneumoniae (-ve), Bacillus cereus (+ve) and Staphylococcus aereus (+ve) using zone of inhibition test.

Development of temperature-responsive semi-IPN hydrogels from PVA-PNVC-PAm for controlled release of anti-cancer agent

ABSTRACT A series of semi-interpenetrating polymeric network (semi-IPN) hydrogels were synthesized using poly(vinyl alcohol) (PVA), monomers N-vinylcaprolactam (NVC) acrylamide (Am), and cross-linker bis[2-methacryloyloxy] ethyl phosphate (BMEP). The hydrogels were synthesized by using free-radical polymerization using ammonium persulphate (APS) as an initiator at 60°C. The hydrogels were characterized by various techniques such as Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM) to confirm the formation, crystallinity, and morphological behavior. The swelling behavior at various temperatures and pH conditions showed that the semi-IPN hydrogels were good candidates for temperature-responsive nature. 5-Flurouracil (FU), a model anticancer drug, was successfully encapsulated and the encapsulation efficiency was found in range of 50–74% for different hydrogels. Further, in-vitro release studies were performed to investigate the release mechanism. The cumulative release studies showed that the developed hydrogels are potentially efficient for the gastrointestinal drug delivery of FU.

Synthesis of Novel Hydrogels based Poly(4-Hydroxyphenylazo-3-N-(4-hydroxyphenyl)maleimide) for Specific Colon Delivery of Chemotherapeutic Agent -

In recent years azo functionalized polymeric hydrogels are very interesting; it is due to their promising applications in various fields especially in the colon drug delivery. 4-Hydroxyphenylazo-3-N-(4-hydroxyphenyl)maleimide (HPM) was synthesized and used for development of hydrogels by free radical polymerization with acrylamide (Am) and N,N-methylene bis acrylamide. Synthesized poly(Am-co-HPM) (PAH) hydrogels were used for encapsulation of 5-fluorouracil (5-FU) an anticancer drug. Structural, thermal, morphological and drug distribution of PAH hydrogels were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction techniques, respectively. Maximum percentage of encapsulation efficiency i.e. 78.25±1.3 was observed for AZ1 PAH hydrogels. 5-FU release studies were performed by in vitro method in simulated gastro intestinal fluids (pH 1.2 & 7.4). To support the 5-FU release mechanism from PAH hydrogels, swelling and deswelling kinetics were studied in doubly distilled water.