The present invention relates to the field of nanotechnology, in particular, to the production of biodegradable polymeric nanoparticles. The present invention provides a biodegradable polymeric nanoparticle made up of a block copolymer and a process for producing the same. The nanoparticles are produced without the use of any emulsifiers and have a size ranging from 30-120 nm. The methods of controlling the drug loading capacity are disclosed along with the process of producing entity-loaded nanoparticles. Compositions comprising the nanoparticles and their use in therapeutics, diagnostics and theranostics are also disclosed.