Micellization and sustained drug release behavior of EC-g-PPEGMA amphiphilic copolymers

Abstract

abstract The micellization and sustained drug release behavior of ethyl cellulose graft poly(poly(ethylene glycol)methyl ether methacrylate) (EC-g-PPEGMA) copolymers with well-defined structure were investigatedbyusingpyreneasthefluorescentprobeandmodeldrug.ItwasfoundthattheEC-g-PPEGMAcopolymershave a low critical micelle concentration (CMC) at about 5×10 −4 mg/mL. Drug loading experimentsindicate that a low graft density of the copolymers corresponds to a higher drug loading efficiency anda higher loading capacity of drug in the micelles. The release rate of the loaded pyrene depends on boththe length of the side chains and the loading capacity of pryene in the micelles. A shorter side chain ofthe copolymer and a higher ratio of the copolymer to the pyrene in the micelles correspond to a lowerrelease rate. The self-assembly system shows a potential application in controlled drug delivery.© 2010 Elsevier Ltd. All rights reserved. 1. IntroductionCellulose is the most abundant renewable biomacromoleculein nature. Cellulose and its derivatives have the advantagesof nontoxicity, biocompatibility, and biodegradability, and havebeen widely used in the fields of composites (CancheEscamilla,RodriguezTrujillo,HerreraFranco,Mendizabal,PHebeish,Waly,Abdel-Mohdy,ASrivastavaBWaly,Abdel-Mohdy,Aly, & Hebeish, 1998), drilling-mud additives (Zhang, Tan, & Li,1999), microfiltration membranes (Rajam & Ho, 2006), separation(Yu, Fu, Zhao, Liu, & He, 2006), absorbent resins (Pourjavadi &Mahdavinia, 2005), flocculants (Biswal & Singh, 2006), solid–solidphase change materials (Li, Liu, & Huang, 2008), and drug delivery(Dong et al., 2008).The micelle formation, as well as their application in the fieldsof medicine and biology has been investigated extensively in the