Abstract
The area of drug delivery through biodegradable microspheres and nanospheres has grown immensely in the past few years. The inherent limitation of these delivery systems in prolonging the release of the encapsulated drug is their uptake by the macrophages (located in the mononuclear phagocyte system) mainly in the liver and spleen. This factor limits their circulation time and hence the clinical effectiveness of the encapsulated drug. Therefore an agent is needed that can provide a chemical camouflage to these microspheres and nanospheres in order to make them long-circulating carriers.
Polyethylene glycol (PEG), a hydrophilic, US FDA-approved polymer, provides the solution to this difficult problem. Biodegradable microspheres and nanospheres possessing a hydrophilic, dysopsonic, PEG-based coating are suitable candidates for the fabrication of long-circulating carriers and have modified pharmacokinetic and pharmacodynamic properties that lead to an increase in the clinical effectiveness of the encapsulated drug. This review discusses the rationale behind the development of PEGylated microspheres and nanospheres and provides an insight into their preparation, characterization, and various drugs/proteins encapsulated in such systems. The PEGylated preparations currently available on the market and those that are about to enter the market are also discussed.
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We are thankful to the University Grants Commission for providing us financial assistance. The authors have no conflicts of interest that are directly relevant to the content of this review.
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Sinha, V.R., Aggarwal, A. & Trehan, A. Biodegradable PEGylated microspheres and nanospheres. Am J Drug Deliv 2, 157–171 (2004). https://doi.org/10.2165/00137696-200402030-00002
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DOI: https://doi.org/10.2165/00137696-200402030-00002