Arindam Giri

Polymer hydrogel from carboxymethyl guar gum and carbon nanotube for sustained trans-dermal release of diclofenac sodium.

Novel carboxymethyl guar gum (CMG)-chemically modified multiwalled carbon nanotube (MCNT) hybrid hydrogels were synthesized at different MCNT levels as potential device for sustained trans-dermal release of diclofenac sodium. Spectroscopy together with morphology, thermogravimetry, and rheological studies proved relatively strong CMG-MCNT interaction at 0.5 and 1 wt% levels of MCNT whereas de-wetting was increased with higher MCNT concentration. Drug encapsulation tendency increased with addition of MCNT; maximum entrapment was noticed at 1 wt% MCNT level. Hydrogels containing 0.5, 1 and 3 wt% MCNT exhibited slower trans-dermal release than neat CMG due to slightly higher gel viscosity and more drug entrapment. Slowest but steady release was obtained from 1 wt% MCNT loaded hydrogel due to highest viscous resistance among all other hybrid nanocomposites.

Acrylic acid grafted guargum–nanosilica membranes for transdermal diclofenac delivery

Green, hydrophobic device for controlled transdermal release of diclofenac sodium was designed from in situ nanosilica/acrylic acid grafted guargum membranes. Best grafting condition was assigned and nanocomposites were formed in situ using varying proportions of aqueous nanosilica sol. Nanocomposite/drug conjugates were formed by bringing down the medium pH from 9.0 to 7.0. The conjugates were characterized through infrared and solid state NMR spectroscopy, electron microscopy, hydro-swelling, surface contact angle, viscometry and biocompatibility. Most balanced property was exhibited by the membrane containing 1wt% nanosilica. It also had shown the highest encapsulation efficacy vis-à-vis slowest release as compared to others during experimentation in a Franz diffusion cell.

Uniquely different PVA-xanthan gum irradiated membranes as transdermal diltiazem delivery device.

This paper reports interesting differences between physical and mechanical properties of various membranes prepared from high and low molecular weight poly (vinyl alcohol) (PVA) and xanthan gum (XG) blends irradiated under low dose electron beam. The membranes were designed for sustained delivery of diltiazem hydrochloride through skin. Electron beam irradiation produced crosslinks and turned PVA into crystalline phase from its amorphous organization in the unirradiated state. PVA crystals were fibrillar at low XG content (1 wt.%) when the molecular weight was high while similar orientation at higher XG content (5 wt.%) when the molecular weight was low. Low molecular weight PVA-XG membranes showed equivalent physical properties under dry condition but wet-mechanical properties were superior for high molecular weight PVA-XG hybrids. Both of them showed slow and sustained diltiazem release but the later induced slightly slower release despite low drug encapsulation efficiency due to its better wet mechanical strength.

Fabrication of acrylic acid grafted guar gum-multiwalled carbon nanotube hydrophobic membranes for transdermal drug delivery

Environmentally stable acrylic acid (AA) grafted guar gum (GG)-carboxy functionalized multiwalled carbon nanotube (f-MWCNT) in situ composite membranes for the sustained release of a hydrophobic drug, namely, diclofenac sodium, have been developed and characterized. Absolute matrix–filler interaction, particularly up to 1 wt% f-MWCNT concentration, instigated finer dispersion of the filler and subsequent increase in the water resistance and drug retention properties of the composites compared to the 2 and 3 wt% levels. The latter showed non-uniform filler networking and eventually resulted in poor water resistance and drug retention behaviors. The slowest drug release was achieved at the 1 wt% f-MWCNT level and fastest was observed at 3 wt% (21.5% vs. 48.5%). The releases followed a non-Fickian mechanism with the greater influence of viscoelastic relaxation at 0.5 and 1 wt% compositions compared to 2 and 3 wt% compositions, respectively.

A transdermal device from 2-hydroxyethyl methacrylate grafted carboxymethyl guar gum–multi-walled carbon nanotube composites

A hydrophobic and biocompatible transdermal device has been developed from 2-hydroxyethyl methacrylate (HEMA) grafted carnboxymethyl guar gum (CMG)-functionalized multi-walled carbon nanotube (MWCNT) in situ composite membranes. The developed composites may be used for sustained delivery of diclofenac sodium. Supreme matrix–MWCNT interaction at 0.5 and 1 wt% MWCNT concentrations induces excellent copolymer-adsorbed fibrillar orientation of MWCNT compared to that at 2 and 3 wt%. It successively leads to efficient encapsulation and more sustained release of the drug molecules at these compositions (65% vs. 17% at 1 wt%). Analyses show that the releases are dominated by the viscoelastic relaxation behavior (power law indices 0.75 and 0.80 and extremely high Deborah numbers) of the devices. Conversely, for the latter, the releases are comparatively less sustained and more swelling controlled (indices are 0.5 and 0.6 and low Deborah numbers). However, all devices have significantly increased the half life period of the drug molecules (2.5 h vs. 47 h at 1 wt%).

Polyelectrolytic aqueous guar gum for adsorptive separation of soluble Pb(II) from contaminated water

The article introduces the concept of homophase adsorption of soluble Pb(II) from contaminated water using aqueous guar gum (GG). The process appears to be extremely handy since it avoids hectic sample preparation and adsorbent recovery stages. The results show that, addition of only 1000 ppm GG removes 56.72% of the contaminated Pb(II) within 150 min at 303 K. The best working pH has been found to be at 4.5. At this point GG molecules show greatest balance between negative zeta potential and high molecular size. Mechanistically, the adsorption follows Langmuir model since on formation of a monolayer, the positive Pb(II) prevent subsequent adsorption through strong electrostatic repulsion. The adsorption kinetics follows pseudo second order model. Both kinetics and thermodynamics of the process complies with the conventional hetero facial adsorption models despite huge procedural differences.

In-situ silica incorporated carboxymethyl tamarind: development and application of a novel hybrid nanocomposite.

A novel hybrid nanocomposite has been prepared using in situ incorporation of nano-sized filler (silica) onto carboxymethyl tamarind kernel polysaccharide (CMT). Various characterizations were employed to confirm that silica nano particles have been incorporated onto the polymer matrix. Rheological characteristics reveal stronger CMT-Si interaction at 0.5 and 1 wt% level. Beyond 1 wt% Si concentration, the interaction is less and so there is little drop in shear viscosity. Flocculation efficiency increases with incorporation of nano filler, maximum efficacy being observed at 1 wt% silica concentration. All the nanocomposites exhibited better flocculation characteristics in comparison to pure CMT.