Molecular weights of poly(butyl 2‐cyanoacrylate) produced during nanoparticle formation

The molecular weights and distributions of poly(buty1 2‐cyanoacrylate) produced during the formation of nanoparticles under a range of polymerisation conditions have been determined by gel permeation chromatography. The data indicate that the type of steric stabiliser and concentration of the monomer added to the polymerisation medium influences the resulting molecular weight of the polymer. In all systems the bulk of the polymer had a low molecular weight (<10000) but nanoparticles stabilised with dextrans or poloxamer 188 also yielded a high molecular weight component (>20000). The results are interpreted with regard to the possible effects on the degradation of nanoparticles and their drug release characteristics. Tentative proposals are made concerning the mechanisms of nanoparticle formation.