International Journal of Pharmaceutics 298 (2005) 219–232 Pharmaceutical Nanotechnology Micelle-like nanoparticles of PLA–PEG–PLA triblock copolymer as chemotherapeutic carrier Subbu S. Venkatraman a,∗ , Pan Jie a , Feng Min b , Boey Yin Chiang Freddy a , Gan Leong-Huat c a School of Materials Science and Engineering, N4.1-1-30 Nanyang Avenue, Nanyang Technological University, Singapore 639798, Singapore b Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong c Natural Sciences and Science Education, National Institute of Education, Nanyang Technological University, Singapore 637616, Singapore Received 14 December 2004; received in revised form 8 March 2005; accepted 18 March 2005 Abstract Triblock copolymer PLA–PEG–PLA were synthesized using ring opening polymerization with different LA/EG ratio. Micellar aggregates were prepared from these block copolymers and characterized. The degradation characteristics of selected copolymers were assessed in both micellar and film forms. Surface segregation of PEG was also quantified as a function of copolymer composition. Anti-cancer drugs 5-FU and paclitaxel were loaded into the micellar nanospheres with good efficiency. The drug release profile showed good control over the release of paclitaxel from these polymers. © 2005 Elsevier B.V. All rights reserved. Keywords: PLA; PEG; Drug carrier; 5-FU; Paclitaxel 1. Introduction Micelle like nanoparticles are smaller than typical blood cells, such as erythrocytes or lymphocytes (ca. 7–10 m), hence may be injected into the bloodstream. After intravenous injection, such particles may be able to achieve site- or tissue-specific delivery by exploit- ing physiological clearance mechanisms in the body. ∗ Corresponding author. Tel.: +65 6790 4259; fax: +65 6790 9081. The drug incorporated in the particles is then released after the uptake of the nanoparticles inside the cells of the target tissue. Several advantages may be envisaged, such as dose reduction as a consequence of targeting, enhanced efficacy and reduced side effects. However, most particulate delivery systems are eliminated by the reticuloendothelial system (RES) within minutes, irrespective of their chemical composition, after intra- venous injection. These particles accumulate in the liver and spleen following phagocytosis. For targeting 0378-5173/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.ijpharm.2005.03.023