Hydrophilic polymeric nanoparticles as drug carriers

Polymeric hydrophilic nanoparticles have attracted attention because of their potential usefulness as drug-carriers in target specific cells, tissues or nucleus. Applications are expected through injectable, oral, nasal or ocular routes. Hydrophilic nanoparticles have been prepared that are hydrophilic on the surface as well as inside the core; particles have also been made that are hydrophilic on the outer surface but are hydrophobic within the core. External stimuli responsive hydrophilic nanoparticles are yet another new addition to the spectra of new materials in drug delivery. Water soluble as well as insoluble drugs can be entrapped into these polymers by adjusting the hydrophilicity/hydrophobicity of the core of the nanoparticles. The review discusses the requirements that these hydrogel nanoparticles must meet to be effective in drug delivery, and the importance of the preparative methods for controlling their sizes below 100 nm, with narrow size distribution.