Abstract: An objective of the present invention is to provide a self-assembled polymer micelle-type ornithine donor, which has high bioavailability, low toxicity, and high therapeutic effectiveness, even when provided by oral administration. Another objective of the present invention is to provide a self-assembled polymer micelle-type ornithine donor which is effective in preventing or treating hepatic disorders. In order to achieve the above objectives, an acyl group is introduced into the primary amino group in the side chain of an ornithine unit in the poly(ornithine) segment of poly(ethylene glycol)-b-poly(ornithine), which spontaneously forms polymer micelles without polyion complex formation.

Abstract: [Object] To provide a derivative of a short chain fatty acid that can exhibit physiological functions inherent in the short chain fatty acid. [Solution] Provided is a block or graft copolymer including a hydrophobic segment of a repeat unit containing a short chain fatty acid ester that is hydrolyzable by esterase in vivo and a hydrophilic segment including a poly(ethylene glycol) chain. These copolymers are effective in the treatment or therapeutic treatment of various diseases or disorders, including cancer.