This article concentrates mainly on fabrication of porous nanoparticles, its characterisation and its use for controlled release of drug. It also encompasses the strategies that have been used to translate and fabricate a wide range of particulate carriers e.g., nanospheres, liposomes, micelles, oil-in-water emulsions, with prolonged circulation and/or target specificity. Sol-gel technique is one of the most widely used techniques to fabricate porous nanoparticles within the polymer. Such nanoparticles have also applications in vascular drug delivery and release, site-specific targeting, as well as transfusion medicine. With regard to the targeting issues, attention is particularly focused on the importance of physiological barriers. We have also critically reviewed and assessed the fate and activity of biodegradable polymeric drug delivery vehicles because the uniformity in degradation of these polymers is questionable. This article will highlight rational approaches in design and surface engineering of nanoscale vehicles and entities for site-specific drug delivery. Potential pitfalls or side effects associated with nanoparticles are also discussed.