Novel PDLLA/PEG copolymer micelles as drug carriers
- 1 January 1996
- journal article
- Published by Taylor & Francis Ltd in Journal of Biomaterials Science, Polymer Edition
- Vol. 7 (4), 359-373
- https://doi.org/10.1163/156856295x00373
Abstract
In this study we attempted to develop a novel drug delivery system in the form of polymeric micelles. In order to obtain polymer chains with micelle forming abilities, we have proposed to produce copolymers by transesterification of poly(DL-lactic acid) (PDLLA) (as the hydrophobic segment) and polyethylene glycol (PEG) (as the hydrophilic segment). We first produced homopolymers of PDLLA with low molecular weights by condensation polymerization of DL-lactic acid. The PDLLA homopolymer with an average molecular weight of 1866 ± 100 was then transesterified with PEG with a molecular weight range of 3300-4000. By changing the ratio of PEG to PDLLA, we were able to produce copolymers with different chain structures, and therefore, with different micelle forming abilities. FTIR, 1H-NMR, DSC, and GPC studies were performed to describe the structures of these PDLLA/PEG copolymers. Micelles of these copolymers were characterized by light scattering. We selected a model drug, i.e. adriamycin, and obtained the drug loadings to the PDLLA/PEG copolymer micelles. The maximum drug loading was about 12 mg g-1. We found that these micelles were degraded in phosphate buffer (pH 7.4 and temperature 37°C) in about 5-6 weeks. We also investigated the release of adriamycin from these PDLLA/PEG micelles, and concluded that the drug release from these micelles was mainly 'degradation controlled'.Keywords
This publication has 11 references indexed in Scilit:
- Effects of soft segments and hydrolysis on the crystallization behavior of degradable poly(oxyethylene)/poly(L‐lactide) block copolymersMacromolecular Chemistry and Physics, 1994
- Biodegradable Long-Circulating Polymeric NanospheresScience, 1994
- Polymerization of lactones, 17. Synthesis of ethylene glycol‐L‐lactide block copolymersDie Makromolekulare Chemie, 1993
- Prevention of protein adsorption and platelet adhesion on surfaces by PEO/PPO/PEO triblock copolymersBiomaterials, 1992
- Poly(ethylene oxide)-graft-poly(L-lysine) copolymers to enhance the biocompatibility of poly(L-lysine)-alginate microcapsule membranesBiomaterials, 1992
- Synthesis and characterization of block copolymers from D, L-lactide and poly(ethylene glycol) with stannous chlorideJournal of Polymer Science Part C: Polymer Letters, 1990
- Preparation, characterization, and properties of polylactide (PLA)–poly(ethylene glycol) (PEG) copolymers: A potential drug carrierJournal of Applied Polymer Science, 1990
- “Super microcapsules” (SMC). I. Preparation and characterization of star polymethylene oxide (PEO)-polylactide (PLA) copolymersJournal of Polymer Science Part A: Polymer Chemistry, 1989
- Biodegradable PEO/PLA block copolymersJournal of Biomedical Materials Research, 1988
- Preparation and properties of D,L-lactide and ethylene oxide copolymer: A modifying biodegradable polymeric materialJournal of Polymer Science Part C: Polymer Letters, 1986