Tridib Bhunia

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%).

SWELLING DESWELLING STUDIES AFTER FREEZE–THAW TREATMENT OF NANOSILICA REINFORCED POLY (VINYL ALCOHOL)-BASED ORGANIC–INORGANIC HYBRID HYDROGEL

Aqueous nanosilica sol (particle size range: 9–13 nm, pH: 9.0) was added at various low concentration range (0.5–2 wt.%) into aqueous poly (vinyl alcohol) (PVA) of different molecular weight (98% hydrolyzed, 20 wt.%) (pH: 5.0) at room temperature under constant stirring to synthesize organic-inorganic hybrid hydrogels in presence of sodium lauryl sulphate as a silica dispersant. Buffer tablets were added to arrest the pH at 9.0 (to prevent any silica aggregation due to change in pH). The resultant hybrids were cast on Teflon sheets and dried in an oven at 50°C to drive out all the unbound water. Those films were then subjected to freese-thaw treatment continuously for 5 h. The freese-thawed films appeared opaque. The swelling-de swelling experiments with the hydrogels were carried out in distilled water at room temperature and consequently allowed to de-swell naturally. Those observations were correlated with the microstructures of the hybrid hydrogels.