Temperature-Triggered Nanosphere Formation Through Self-Assembly of Amphiphilic Polyphosphazene

• Published in: Macromolecular chemistry and physics Vol. 207; no. 14; pp. 1289 - 1296
• Main Authors: Zhang, Jian Xiang, Qiu, Li Yan, Wu, Xiao Li, Jin, Yi, Zhu, Kang Jie
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 24.07.2006; WILEY‐VCH Verlag; Wiley
• Subjects: amphiphilic copolymer; Applied sciences; Biological and medical sciences; drug delivery; Exact sciences and technology; General pharmacology; Inorganic and organomineral polymers; Medical sciences; nanospheres; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Physicochemistry of polymers; polyphosphazene; Preparation; self-assembly; polyphosphazene; Graft copolymer; Nanoparticle; nanospheres; Temperature effect; Drug carrier; Acrylamide derivative copolymer; drug delivery; Cloud point; amphiphilic copolymer; Ibuprofen; Molecular aggregation; Release; Amphiphilic polymer; Phosphazene copolymer; Control release polymer; In vitro; Non steroidal antiinflammatory agent; self-assembly; Morphology; Preparation; Monodispersed particle; Kinetics; Spherical particle; Aqueous solution; Lattice structure
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.200600139

An amphiphilic graft polyphosphazene with a molar ratio of poly(N‐isopropylacrylamide) (PNIPAm) to ethyl glycinate (GlyEt) of 0.54:1 was synthesized. This copolymer in aqueous solution exhibited two temperature induced phase transitions at 17.2 and 33.7 °C, which correspond to the transformation of primary aggregate morphology (at Tph1) and the collapse of PNIPAm chains (at Tph2) respectively. Network micelles were assembled in water at lower temperature (far below Tph1), and then narrowly dispersed nanoparticles were formed above Tph1, while inter‐nanoparticle aggregation occurred due to the collapse of PNIPAm chains surrounding the GlyEt core when the temperature was above Tph2. Through solubilization of the hydrophobic drug ibuprofen into polymeric aggregates at lower temperature, drug loaded nanospheres were prepared successfully. In vitro release revealed that sustained drug release was achieved with this novel delivery system. These results suggest that this novel copolymer could be used as a potential drug carrier, especially for the delivery of hydrophobic biocompounds through parenteral administration. Schematic illustration of the temperature‐triggered self‐assembly process of PNIPAm/GlyEt‐PPP in aqueous solution.