title: Cross-linked nanoassemblies from poly(ethylene glycol)-poly(aspartate) block copolymers as stable supramolecular templates for particulate drug delivery.
abstract: Block copolymer cross-linked nanoassemblies (CNAs) were developed as stable supramolecular templates for particulate drug delivery. Poly(ethylene glycol)-poly(aspartate) [PEG-p(Asp)] block copolymers, consisting of PEG (5 or 12 kDa) and Asp (5, 14, 25, 33, and 37 repeating units), were used as scaffolds and grafts in combination to prepare a nanoassembly library of grafted nanoassemblies (GNAs) and CNAs. Four synthesis routes were tested to maximize the number of drug-binding Asp units per nanoassembly. Grafting-onto-scaffold and grafting-from-scaffold methods were used for GNA synthesis. Either partially or completely deprotected PEG-p(Asp) was cross-linked with diamine compounds to prepare CNAs. (1)H NMR and GPC measurements showed that GNAs and CNAs contained the maximum 183 and 253 Asp units, respectively. Initial screening of the nanoassemblies revealed that GNAs would be impractical for further development as drug carriers due to variable grafting efficiency and low product yields. CNAs were obtained in high yields and identified as a promising supramolecular template that can entrap and release ionizable drugs (doxorubicin), enhancing the particle stability of nanoassemblies in the pharmaceutically relevant pH ranges between 4 and 9. Light scattering measurements demonstrated that the particle size of CNAs remained uniform before and after drug entrapment, causing neither aggregation nor dissociation (<5 mg/mL).
authors.affiliation: College of Pharmacy, Pharmaceutical Sciences, University of Kentucky, 789 South Limestone, Lexington, Kentucky 40536-0596, USA.
authors.forename: Hyun Jin
authors.initials: HJ
authors.lastname: Lee
authors.forename: Younsoo
authors.initials: Y
authors.lastname: Bae
mesh_terms: D003432:Cross-Linking Reagents / Q000138:chemical synthesis / Q000737:chemistry*; D004317:Doxorubicin / Q000737:chemistry*; D016503:Drug Delivery Systems; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances / Q000138:chemical synthesis / Q000737:chemistry; D015394:Molecular Structure; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism; D013499:Surface Properties
chemical_list: D003432:Cross-Linking Reagents; D046911:Macromolecular Substances; C493635:polyethylene glycol-block-polyaspartic acid; D011092:Polyethylene Glycols; D004317:Doxorubicin