Polymer Drugs and Polymeric Drugs X: Slow Release of 5-Fluorouracil from Biodegradable Poly(γ-Glutamic Acid) and its Benzyl Ester Matrices

We prepared poly(γ-glutamic acid)(γ-PGA) benzyl ester(γ-PBG) by the esterification of γ-PGA and benzyl bromide and evaluated the degradation behavior and its usefulness as a drug delivery system (DDS) matrix using 5-fluorouracil (5-FU) as a model drug. γ-PBG degraded in an acidic solution gradually for up to 130 days, and degraded very slowly in a phosphate buffer solution (pH 7.4). After 150 days, the weight loss of the γ-PBG film was only 10% in a phosphate buffer solution. A slow release of 5-FU from γ-PBG films was achieved. The release rate was affected by the pH of the outer solution and the loading drug. We observed an initial burst-release on the first day, after that, the release of 5-FU was diffusion-controlled. γ-PBG may be a novel biodegradable material that may be useful in the pharmaceutical, biomedical, and agricultural fields.