Green synthesis of silver nanoparticles from medicinal plants and evaluation of their antiviral potential against chikungunya virus.

The exploration of nanoscale materials for their therapeutic potential against emerging and re-emerging infections has been increased in recent years. Silver nanoparticles (AgNPs) are known to possess antimicrobial activities against different pathogens including viruses and provide an excellent opportunity to develop new antivirals. The present study focused on biological synthesis of AgNPs from Andrographis paniculata, Phyllanthus niruri, and Tinospora cordifolia and evaluation of their antiviral properties against chikungunya virus. Synthesized plants AgNPs were characterized to assess their formation, morphology, and stability. The cytotoxicity assays in Vero cells revealed that A. paniculata AgNPs were most cytotoxic with maximum non-toxic dose (MNTD) value of 31.25 µg/mL followed by P. niruri (MNTD, 125 µg/mL) and T. cordifolia AgNPs (MNTD, 250 µg/mL). In vitro antiviral assay of AgNPs based on degree of inhibition of cytopathic effect (CPE) showed that A. paniculata AgNPs were most effective, followed by T. cordifolia and P. niruri AgNPs. The results of antiviral assay were confirmed by cell viability test using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) dye, which revealed that A. paniculata AgNPs inhibited the virus to a maximum extent. The cell viability of CHIKV-infected cells significantly increased from 25.69% to 80.76 and 66.8%, when treated with A. paniculata AgNPs at MNTD and ½MNTD, respectively. These results indicated that use of plants AgNPs as antiviral agents is feasible and could provide alternative treatment options against viral diseases which have no specific antiviral or vaccines available yet.

In vitro release profile of anti-ulcer drug rabeprazole from biocompatible psyllium-PVA hydrogels.

The present article discusses the synthesis, characterization and haemocompatibility behaviour of the psyllium-PVA hydrogels prepared by chemical method in the presence of N,N'-methylenebisacrylamide. These hydrogels have been characterized by Fourier Transform infrared spectroscopy, thermo gravimetric analysis, swelling and drug release studies. The release of model drug rabeprazole sodium from the drug loaded hydrogels occurred through non-Fickian diffusion mechanism. Psyllium itself acts as anti-ulcer agent and release of rabeprazole from the drug loaded hydrogels may enhance the curing potential of the drug delivery device. The haemocompatibility was evaluated by studying the blood interactions with hydrogels with reference to thrombogenicity and haemolytic potential. Thrombogenicity results indicate that hydrogels are non-thrombogenic as the weight of clot formed and thrombus percentage for hydrogels was less than the positive control. The haemolytic index has been observed <5%. These observations indicate that these hydrogels are haemo-compatible and hence could be used for oral administration of antiulcer drugs.

Design of psyllium-PVA-acrylic acid based novel hydrogels for use in antibiotic drug delivery.

In order to exploit the potential of gel forming medicinally important polysaccharide, we have developed psyllium based hydrogels through graft copolymerization. The optimum conditions for the synthesis of psyllium-poly(vinyl alcohol) (PVA)-poly(acrylic acid) blended hydrogels have been evaluated and their characterization has been carried out by SEMs, FTIR and swelling studies. The optimum conditions for the synthesis of hydrogels have been obtained as 1% (v/v) acrylic acid, 2% (w/v) PVA and 1g of psyllium. The use of very small amount of these petroleum products has developed the low energy, cost effective, biodegradable and biocompatible material for potential biomedical applications. It is the novelty of the present finding. The release of model antibiotic drug tetracycline HCl from the hydrogels has been observed more in pH 2.2 buffer hence these hydrogels are suitable for peptic ulcer caused by Helicobacter pylori. At the same time psyllium has also been reported to cure the ulcerative colitis. Hence, the present drug delivery system will have double potential to cure ulcer. The values of the diffusion exponent for the release of drug have been obtained as (0.774, 0.576 and 0.858) and gel characteristic constant have been (8.884x10(-3), 24.149x10(-3) and 3.989x10(-3)) respectively in pH 2.2 buffer, 7.4 buffer and distilled water. The release of the drug from the hydrogels occurred through non-Fickian diffusion mechanism.

Radiation crosslinked polymerization of methacrylamide and psyllium to develop antibiotic drug delivery device.

Psyllium is a medicinally important polysaccharide and its modification with methacrylamide through radiation crosslinked polymerization will develop hydrogels meant for drug delivery applications. The present paper deals with the preparation of hydrogels and their characterization by SEMs, FTIR, TGA and swelling studies. The release dynamics of model antibiotic drug rifampicin from the hydrogels has been studied for the evaluation of the release mechanism. The values of the diffusion exponent 'n' have been obtained (0.64, 0.58 and 0.57), respectively, in distilled water, pH 2.2 buffer and pH 7.4 buffer. The release of the drug from the hydrogels occurred through non-Fickian diffusion mechanism.