Physicochemical characterization of polymeric micelles constructed from novel amphiphilic polyphosphazene with poly(N-isopropylacrylamide) and ethyl 4-aminobenzoate as side groups.
An amphiphilic graft polyphosphazene (PNIPAm/EAB-PPP) composed of oligo-poly(N-isopropylacrylamide) (PNIPAm) as hydrophilic segments and ethyl 4-aminobenzoate (EAB) as hydrophobic groups was synthesized via ring-opening polymerization and subsequent substitution reaction. The molar ratio of the PNIPAm segment to EAB group was 1.85:0.15. The lower critical solution temperature (LCST) of copolymer was 32.6 degrees C as determined by turbidity method. Micellization behavior of PNIPAm/EAB-PPP in an aqueous phase was characterized by fluorescence technique, 1H NMR, dynamic light scattering (DLS) and transmission electron microscopy (TEM). The critical micelle concentration (CMC) of the graft copolymer in aqueous solution was 0.1mg/ml. The number-averaged particle size of spherical micelles was 80 nm at 25 degrees C with a narrow distribution. TEM also revealed that inter-micellar aggregation was induced in the micelle solution at temperature above LCST of graft copolymer. The thermosensitive PNIPAm/EAB-PPP micelles may be of help to regulate the loading and release of hydrophobic drugs.
Zhang
Jian Xiang
JX
College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310031, China.
Qiu
Li Yan
LY
Jin
Yi
Y
Zhu
Kang Jie
KJ
D000180:Acrylic Resins / Q000737:chemistry*; D001566:Benzocaine / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D046529:Microscopy, Electron, Transmission; D009943:Organophosphorus Compounds / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012542:Scattering, Radiation; D012996:Solutions; D013050:Spectrometry, Fluorescence; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
D000180:Acrylic Resins; D008823:Micelles; D009943:Organophosphorus Compounds; D011108:Polymers; D012996:Solutions; C469412:poly(N-isopropylacrylamide-co-acrylamide); C108974:poly(phosphazene); D001566:Benzocaine