K. Madhusudana Rao

Curcumin encapsulated pH sensitive gelatin based interpenetrating polymeric network nanogels for anti cancer drug delivery.

Interpenetrating polymeric network nanogels (IPN-NGs) composed of natural gelatin biological protein macromolecules and poly(acrylamidoglycolic acid) were produced by simple free radical emulsion polymerization. The developed IPN-NGs were characterized by Fourier-transform infra-red spectroscopy to confirm the formation of NGs. The hydrophobic curcumin drug was loaded successfully into these NGs using an in-situ method. The curcumin-encapsulated NGs were well dispersed in aqueous solutions and showed good bioavailability. Curcumin was dispersed molecularly in the IPN-NGs, which was confirmed by differential scanning calorimetry and X-ray diffraction. The NGs exhibited pH sensitive properties according to dynamic light scattering and the zeta size potentials. Transmission electron microscopy revealed the NGs to be spherical, approximately 100nm in size. The encapsulation efficiency of these IPN-NGs drug formulations ranged from 42 to 48%. In addition, the release of curcumin from the NGs was examined in phosphate buffer medium. The cytotoxicity of the IPN-NGs was studied using in vitro cultures of fibroblasts and a colorectal cancer cell line. The results suggest that the newly developed pH sensitive gelatin-poly(acrylamidoglycolic acid)-curcumin NGs can be applied for colorectal cancer drug delivery applications.

Synthesis of alginate based silver nanocomposite hydrogels for biomedical applications

Sodium alginate and poly(acrylamide-co-N-vinylcaprolactam-co-acrylamidoglycolic acid) based dual responsive 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 onto these semi-IPN hydrogels via equilibrium swelling method. The hydrogels were also used as templates for the production of 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 spectroscopy and 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 temperature conditions. In vitro release of 5-fluorouracil from these SA-PAVA hydrogels was carried out in gastro-intestinal fluids different temperatures. The SA-PAVA hydrogel/silver nanocomposites showed excellent anti-bacterial activity towards Escherichia coli and Bacilli.

Biodegradable sodium alginate-based semi-interpenetrating polymer network hydrogels for antibacterial application

A series of biodegradable, semi-interpenetrating polymer network (semi-IPN) hydrogels were synthesized from a combination of carbohydrate polymer and sodium alginate (NaAlg) with acrylamide and dimethyl aminoethyl methacrylate, and crosslinked with N,N-methylenebisacrylamide via radical redox polymerization. The cytocompatibility of the hydrogels with respect to their monomers and semi-IPN hydrogels was evaluated in vitro using cultures of mouse fibroblast cell lines. This study allowed the entrapment of silver nanoparticles (NPs) into semi-IPN hydrogel networks by the in situ reduction of Ag(+) ions using NaBH4 as a reducing agent. UV-visible spectroscopy confirmed the formation of silver NPs in the semi-IPN hydrogel matrix. The formation of silver NPs was also confirmed from a themogravimetric analysis weight loss difference between hydrogel and silver nanocomposite as 32%. The morphology and structure of the AgNPs present in the hydrogel networks were examined by scanning electron microscopy. Transmission electron microscopy revealed silver NPs with a size of ∼5 nm. The silver nanocomposite hydrogel exhibited good antibacterial activity against both gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria. These results suggest that the hydrogel can be applied as wound dressings and for water purification purposes.

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.