Graft copolymers of bacterial polyesters were prepared by direct condensation of poly(3‐hydroxyoctanoate‐co‐9‐carboxy‐3‐hydroxydecanoate) (PHOD) and poly(ethylene glycol) (PEG) or poly(lactic acid) (PLA). Nanoparticles from PHO, PHOD, PHOD‐g‐PEG, and PHOD‐g‐PLA were obtained by solvent displacement without stabilizer, and their stability in different aqueous media with different salt concentrations were studied. The results showed that the presence of hydrophilic PEG on the particle surface prevents the aggregation promotion by salts in aqueous solution. PHOD‐g‐PEG appears to be a promising candidate for site‐specific drug delivery systems.
