high performance liquid chromatography hplc using a hewlett packard series 1050 germany the antisense oligonucleotide isis 2922 was obtained from pharmacia biotech cambridge united kingdom and analyzed by zone capillary electrophoresis the sambucus nigra lectin was obtained from vector laboratories usa and determined by gel permeability chromatography the samples of nanoparticles were lyophilized using a virtis genesis 12el apparatus usa the process described below is valid for the preparation of colloidal pharmaceutical forms nanoparticle type which can be used for the administration of drugs or biologically active molecules in addition these nanoparticles can also be used for the film coating of macroscopic pharmaceutical forms such as tablets granules granulates and minigranules 100 mg of poly methyl vinyl ether co maleic anhydride copolymer are dissolved in 5 ml organic solvent acetone then under stirring 10 ml of a miscible organic solvent ethanol and 10 ml distilled water are added the resulting mixture is stirred for homogenization during 5 minutes and the suspension of nanoparticles is evaporated under reduced pressure for organic solvents elimination the final volume is adjusted with water or an aqueous solution to 10 ml the next step is to cross link the resulting nanoparticles with 1 3 diaminopropane dp in order to do this a dp solution is prepared in water 1 v v and a predetermined amount of cross linking agent is added to the suspension of nanoparticles for incubation for 5 minutes the suspension is then purified by ultracentrifugation 12 minutes at 10 000 rpm or tangential filtration the supernatants are eliminated and the residues are resuspended in water or in an aqueous solution of mannitol 5 w v finally the resulting suspension of nanoparticles is lyophilized maintaining all its properties poly methyl.