The drug release and degradation behavior of two double-walled microsphere formulations consisting of a doxorubicin-loaded poly(d,. l-lactic-co-glycolic acid) (PLGA) core (~46 kDa) surrounded by a poly(d,. l-lactic acid) (PDLLA) shell layer (~55 and 116 kDa) were examined. It was postulated that different molecular weights of the shell layer could modulate the erosion of the outer coating and limit the occurrence of water penetration into the inner drug-loaded core on various time scales, and therefore control the drug release from the microspheres. For both microsphere formulations, the drug release profiles were observed to be similar. The degradation of the microspheres was monitored for a period of about nine weeks and analyzed using scanning electron microscopy, laser scanning confocal microscopy, and gel permeation chromatography. Interestingly, both microsphere formulations exhibited occurrence of bulk erosion of PDLLA on a similar time scale despite different PDLLA molecular weights forming the shell layer. The shell layer of the double-walled microspheres served as an effective diffusion barrier during the initial lag phase period and controlled the release rate of the hydrophilic drug independent of the molecular weight of the shell layer.
|Number of pages||10|
|State||Published - May 2013|
Bibliographical noteFunding Information:
The authors acknowledge the funding support from the National Institutes of Health (NIH, USA) and National Medical Research Council (NMRC, Singapore) under the grant numbers 1R01EB005181 and NMRC EDG11may084 , respectively. Qingxing Xu acknowledges the scholarship support from Agency for Science, Technology and Research (A*STAR, Singapore) for NUS-UIUC Joint Ph.D. Program.
- Double-walled microspheres
ASJC Scopus subject areas
- Ceramics and Composites
- Mechanics of Materials