Abstract: Application of nanoparticles based on hydrophilic polymers as pharmaceutical forms for the administration of active macromolecules. The nanoparticles (having a nanometric size and a hydrophilic character), also called nanospheres or latex, are colloidal systems comprised of the combination of hydrophilic polymers and an active ingredient having a high molecular weight (active macromolecule, molecular weight higher than 1000 daltons). The hydrophilic polymers are the chitosan (an aminopolysaccharide) or its derivatives and polyoxyethylene or its derivatives. The association of the active macromolecule to said nanoparticles takes place in an aqueous phase without having to use organic solvents or auxiliary toxic substances. The active ingredient charge capacity of the nanoparticles is extremely high and additionally said charge is released in a controlled and time extended way. Additionally, said nanoparticles have a positive surface electric charge whose intensity may vary in relation to its composition.