Background & Objectives: Polymers as drug carriers are recent advances in drug delivery and led to the new advent field that called polymer treatment. In the present study, the toxic and teratogenic effects of BDP18 were evaluated against chicken embryos as a model.

  Methods: The BDP18 tri-block copolymer (PLA-PEG2000-PLA) was synthesized. The compound solution was injected in triplicate examination, in the air sac of the eggs, at third day of incubation, and survived fraction of the embryos and Morphological and skeletal changes were recorded .

  Results: The survived fraction of the embryos depends on the compound concentration. In concentration of 20 mg/ml , 33.3% of the embryos were survived and the LD₅₀ was 10.87 mg/egg . Morphological study of the treated embryos showed no abnormalities in embryos , and skeletal staining showed the deletion of caudal vertebrate in high concentration.

  Conclusion: The BDP18 copolymer had low toxic and teratogenic effects against the embryos, but it caused the deletion of caudal vertebrate at concentrations above the threshold (10 mg/ml). This polymer can be used as an effective drug -release system in low concentrations .