International Journal of Pharmaceutics 181 (1999) 107 – 115 Release of adriamycin from poly(g-benzyl-L-glutamate)/poly(ethylene oxide) nanoparticles Injoon Oh a, *, Kayoung Lee, Hye-Young Kwon a , Yong-Bok Lee a , Sang-Chul Shin a , Chong-Su Cho b , Chong-Kook Kim c a College of Pharmacy and Research Institute of Drug De6elopment, Chonnam National Uni6ersity, Kwangju, 500 -757, South Korea b Di6ision of Biological Resources and Material Engineering, Seoul National Uni6ersity, Seoul, 151 -742, South Korea c College of Pharmacy, Seoul National Uni6ersity, Seoul, 151 -742, South Korea Received 8 June 1998; accepted 4 January 1999 Abstract Prolonged circulation of anticancer agent in blood is expected to decrease the host toxicity and enhance the anticancer activity. The purpose of this study is to develop and characterize the prolonged and sustained release formulation of anticancer agent using biodegradable poly(g-benzyl-L-glutamate)/poly(ethylene oxide) (PBLG/PEO) polymer nanoparticles. PBLG/PEO polymer is a hydrophilic/hydrophobic block copolymer and forms a micelle-like structure in solution. Spherical nanoparticles incorporating adriamycin were prepared by a dialysis method. The fluorescence intensity of adriamycin in the nanoparticles was increased when sodium dodecylsulfate was added. It is one of the evidences of entrapment of adriamycin in the polymer nanoparticles. Only 20% of entrapped drug was released in 24 h at 37°C a and the release was dependent on the molecular weight of hydrophobic polymer. The endothermic peak of adriamycin at 197°C disappeared in the nanoparticles system, suggesting the inhibition of a crystallization of adriamycin by polymer adsorption during the precipitation process. The mean residence time of adriamycin from the nanoparticles was more than threefold that from a free adriamycin. These results suggest usefulness of PBLG/PEO nanoparticles as a sustained and prolonged release carrier for adriamycin. © 1999 Elsevier Science B.V. All rights reserved. Keywords: Adriamycin; Nanoparticle; Poly(g-benzyl-L-glutamate)/poly(ethylene oxide); Sustained release * Corresponding author. E-mail address: ijoh@chonnam.chonnam.ac.kr (I. Oh) 0378-5173/99/$ - see front matter © 1999 Elsevier Science B.V. All rights reserved. PII:S0378-5173(99)00012-5