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Effect of the inclusion of PEG on the solid‐state properties and drug release from polylactic acid films and microcapsules
Author(s) -
Jonnalagadda Sriramakamal,
Robinson Dennis H.
Publication year - 2004
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.20667
Subject(s) - crystallinity , polylactic acid , materials science , glass transition , chemical engineering , solvent , peg ratio , polymer chemistry , drug delivery , polyethylene glycol , organic chemistry , chemistry , nanotechnology , polymer , composite material , finance , engineering , economics
Abstract The use of poly(lactic acid) (PLA) for controlled drug delivery applications was limited by unfavorable physical properties such as hydrophobicity, high intrinsic crystallinity, low permeability, and high glass transition temperatures. This research used polyethylene glycols (PEGs) of varying molecular weights (300–18,500 g/mol) and concentrations (0–50% w/w) to modify the permeability, intrinsic crystallinity, glass transition temperature, residual solvent levels, and release of a model drug, 5‐flurouracil (5FU), from monolithic films and microcapsules fabricated with PLA. The films were fabricated by solvent casting from methylene chloride. The microcapsules were formed by a coacervation method by using a methylene chloride/hexane solvent/nonsolvent system. Compared to PLA films, all PLA : PEG films showed the following: (1) a glass transition temperature between 40 and 55°C, (2) 5–8% lower residual solvent levels, and (3) enhanced permeability to 5FU. These results suggested that the incorporation of PEG improves the physical properties of PLA films to enable fabrication of controlled release delivery systems. Similar to the films, incorporation of PEG also enhanced the permeability of PLA microcapsules to 5FU. However, high intrinsic crystallinity, dual endothermal character for PLA melting, and significant burst release of 5FU in PLA : PEG microcapsules may limit their development for controlled drug delivery applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2025–2030, 2004