Zidovudine-Chitosan microspheres were prepared by a suspension cross-linking method. The chitosan was dissolved in 2% acetic acid solution and this solution was dispersed in the light liquid paraffin. Span-80 was used as an emulsifier and glutaraldehyde as cross-linking agent. The prepared microspheres were slight yellow, free flowing and characterized by drug loading, infrared spectroscopy (IR), differential scanning colorimetry (DSC) and scanning electron microscopy (SEM). The in-vitro release studies are performed in pH 7.4 buffer solution. Microspheres produced are spherical and have smooth surfaces, with sizes ranging between 60-210 µm, as evidenced by SEM and particle size analysis. The drug loaded microspheres showed up to 60% of entrapment and release was extended up to 18-24 h. Among all the systems studied, the 35% Glutaraldehyde crosslinked, microspheres with 1 : 6 drug/chitosan ratio showed 75% release at 12 h. The infrared spectra and DSC thermograms showed stable character of zidovudine in the drug loaded microspheres and revealed the absence of drug-polymer interactions. Data obtained from in vitro release were fitted to various kinetic models and high correlation was obtained in the Higuchi model. The drug release was found to be diffusion controlled.

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A novel adsorbent, poly(ethyleneimine)-modified poly(acrylic acid)-grafted nanocellulose=nanobentonite superabsorbent hydrogel (PEI-PAA-g-NC=NB) was prepared by free radical graft copolymerization technique and well characterized. Swelling behavior of adsorbent was studied under different pH and temperatures. The various adsorption parameters for the adsorption of the protein, b-Casein (bCN) onto the PEI-PAA-g-NC=NB were investigated. Sips adsorption isotherm and pseudo-first-order kinetic model were best suited for the present adsorbent. The adsorption-desorption experiments were conducted with 0.1 M NaSCN for four cycles. The results of the present investigation proved that PEI-PAA-g-NC=NB is highly effective for the separation of bCN from aqueous solutions.

The implications of the mold metabolites, aflatoxins, as toxic contaminates in human and animal foodstuffs and their suspected involvement in cases of liver cancer, have received widespread attention during the last decade.1) The fluorescence exhibited by afla toxins under ultraviolet light has been utilized as the basis of extremely sensitive method for their detection and estimation. As little as 10-10g can be detected in this way and affords the basis for most of the physicochemical assay procedures.2) Aflatoxins B2a, and G2a are the 2-hydroxy derivatives of aflatoxin B1 and G1 respectively. Carnaghan et al.3) reported the fluorescence properties of aflatoxins B1, B2, G1 and G2 in methanol solution. Later, fluorescence properties in ethanol, chloro form,4) acetonitrile,5) propylene glycol, water,