Chitosan adsorbed microspheres containing tetanus toxoid were prepared in the size range of 10 μm to 75 μm, by emulsion-cross linking technique at different speeds of agitation. The amount of tetanus toxoid incorporated into chitosan microspheres were estimated by limes flocculation test and in vivo evaluation of tetanus toxoid adsorbed chitosan microspheres were determined by toxin neutralization method using albino mice. The results of in vivo release for the batches of 10 μm and 25 μm correlates with the results of in vitro in which both the batches passes the limit of IP standard (4 Lf) where as, for the batches of 50 μm and 75 μm, the in vitro release of tetanus toxoid was 2 Lf. But our in vivo studies for the batches of 50 μm and 75 μm fail to pass the limit stated in IP. The release of tetanus toxoid from the chitosan microspheres was found to be sustained for the period of 6 months.

In the recent decades, polymers are widely used as biomaterials due to their favourable properties such as good biocompatibility, easy design and preparation, structural varieties and interesting bio-mimetic character. The use of biodegradable polymeric nanoparticles (NPs) for controlled drug delivery has shown significant therapeutic potential. Concurrently, targeted delivery technologies are becoming increasingly important as a scientific area of investigation. The current review entails an in-depth discussion of biodegradable polymeric nanoparticles with respect to types, formulation aspects as well as site-specific drug targeting using various ligands modifying the surface of polymeric nanoparticles with special insights to the field of oncology. Ultimately the goal of polymeric nanoparticle drug delivery is the emergence of a nano-fabricated therapeutic drug release device with the capacity to enough hold and release of various active agents on demand.