Controlled release and stealthy circulation of polymersomes

F. Ahmed, P. J. Photos, I. Osmaswa, F. S. Bates, D. E. Discher

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

The biocompatibility and controlled release profiles of polymersome were investigated. These hyperstable self-assembled block copolymers were injected into rats to elucidate in vivo circulation lifetimes, thalf. For these synthetic vesicles, t-half is 20-30 hours, which is comparable to stealth liposomes. Clearance appears to be primarily mediated by opsonization inspite of the heavily PEGylated brush arising from the hydrophilic fractions of all these block copolymers. Nonetheless, the t-half of these polymersomes compares well with any stealth liposome system. Therefore, novel controlled release polymersomes were prepared by blending the hydrolysable block copolymer poly (ethyleneoxide)-poly(lactic acid) (PEO-PLA) with the diblock copolymer poly(ethyleneoxide)-(poly(butadiene) (PEO-PBD). The average time, t-release, for encapsulant release in vitro is obtained from exponential decays in the intact vesicle population and ranges from tens of hours to days or longer. Release kinetics showed minimal difference in plasma at 37°C and the rate depends linearly on the mean molar ratio of PEO-PLA incorporated into the vesicle membrane. We propose a mechanism of membrane poration wherein partially hydrolyzed PLA chains congregate and achieve the desired spontaneous membrane curvature by forming a pore and rupturing the membrane, synonymous with detergent-mediated poration, release, and degradation. Emerging studies probe the encapsulant release dynamics in vivo of systems with t-release ? t-half.

Original languageEnglish (US)
Title of host publicationAnnual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
Pages466-467
Number of pages2
Volume1
StatePublished - 2002
EventProceedings of the 2002 IEEE Engineering in Medicine and Biology 24th Annual Conference and the 2002 Fall Meeting of the Biomedical Engineering Society (BMES / EMBS) - Houston, TX, United States
Duration: Oct 23 2002Oct 26 2002

Other

OtherProceedings of the 2002 IEEE Engineering in Medicine and Biology 24th Annual Conference and the 2002 Fall Meeting of the Biomedical Engineering Society (BMES / EMBS)
CountryUnited States
CityHouston, TX
Period10/23/0210/26/02

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