Fabrication of chitosan microspheres using vanillin/TPP dual crosslinkers for protein antigens encapsulation.

Microspheres were prepared from water soluble chitosan using dual vanillin/TPP crosslinkers. Placebo (C1), Bovine serum albumin (BSA) (C2), monovalent tetanus toxoid (TT) (C3) and divalent tetanus (TT) and diphtheria toxoids (DT) (C4) encapsulated microspheres were studied in terms of size (1-4 µm), encapsulation efficiency (75-80%), swelling and mucoadhesion (56-68%). FT-IR, TGA, XRD and SEM characterization of microspheres suggested specific interaction, more thermal stability, amorphous nature and rough surfaces of encapsulated microspheres. EDS confirmed the co-crosslinking and ninhydrin tests were showing higher crosslinking density. Zeta potential was 47.7 to 66.2 +mV indicating the potential stability of the colloidal system. Equilibrium adsorption isotherms described encapsulated microspheres followed the Langmuir isotherm model, suggesting monolayer adsorption of the mucin on microspheres. In-vitro release studies up to four weeks indicated zero order kinetics and obeyed swelling-controlled super case II transport release mechanism. Thus, the present study could be helpful in developing the multivalent oral vaccine.

An Exceptionally Stable Ti Superoxide Radical Ion: A Novel Heterogeneous Catalyst for the Direct Conversion of Aromatic Primary Amines to Nitro Compounds.

A matrix-bound superoxide radical anion, generated by treating Ti(OR)4 (R=iPr, nBu) with H2 O2 , is a selective heterogeneous catalyst for the oxidation of anilines to the corresponding nitroarenes with 50 % aqueous H2 O2 [Eq. (1)]. Yields of 82-98 % are obtained, even with anilines bearing electron-withdrawing substituents (R=NO2 , COOH).