The present invention relates to a reducing or non-reducing polynucleotide polymer using a nucleotide from AMP, ADP, ATP, GMP, GDP, GTP, CMP, CDP and CTP, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), and N-hydroxy-succinimide (NHS) for drug delivery and a method for preparing same, and provides a reducing or non-reducing polymer synthesized by using nucleotides, a method for preparing same, and a polymer composition for drug delivery containing the reducing or non-reducing polymer. The present invention relates to a drug delivery carrier for delivering proteins or peptides to a targeted area through electrostatic attraction, by obtaining a negatively (−) charged polymer by using nucleotides to synthesize the reducing or non-reducing polymer, which is easily breakable due to disulfide bonds, and then bonding the negatively (−) charged polymer with a positively (+) charged protein or peptide, wherein a polymer derived from a non-viral drug delivery carrier containing the novel reducing or non-reducing polymer is capable of effectively enabling escape of a drug, delivered by means of proton buffering activity, from an endosome to other organelles in a cell.
