title: Poly(ethylene oxide)-modified poly(beta-amino ester) nanoparticles as a pH-sensitive biodegradable system for paclitaxel delivery.
abstract: The main objective of this study was to develop and characterize a pH-sensitive biodegradable polymeric nanoparticulate system for tumor-selective paclitaxel delivery. A representative hydrophobic poly(beta-amino ester) (poly-1) was synthesized by conjugate addition of 4,4'-trimethyldipiperidine with 1,4-butanediol diacrylate. Poly-1 (M(n) 10,000 daltons) nanoparticles were prepared by the controlled solvent displacement method in an ethanol-water system in the presence of Pluronic) F-108, a poly(ethylene oxide) (PEO)-containing non-ionic surfactant. Control and PEO-modified nanoparticles were characterized by Coulter counter, scanning electron microscopy (SEM), zeta potential measurements, and electron spectroscopy for chemical analysis (ESCA). Polymer degradation studies were performed in phosphate-buffered saline (PBS, pH 7.4) at 37 degrees C. Paclitaxel loading capacities and efficiencies were determined and release studies were performed in Tween)-80 (0.1%, w/v)-containing PBS at 37 degrees C. Control and PEO-modified nanoparticles, labeled with rhodamine-123, were incubated with BT-20 cells to examine the uptake and cellular distribution as a function of time. PEO-modified nanoparticles with an average size of 100-150 nm and a positive surface charge of 37.0 mV were prepared. SEM analysis showed distinct smooth, spherical particles. The ether (-C-O-) peak of the C(1s) envelope in ESCA confirmed the surface presence of PEO chains. Polymer biodegradation studies showed that almost 85% of the starting material degraded after 6 days. The maximum paclitaxel loading efficiency attained was 97% at 1.0% (w/w) of the drug. Paclitaxel release studies showed that approximately 10% was released in the first 24 h, 80% after 3 days, and the entire content was released in approximately 5 days. After 1 h of incubation, a large fraction of the administered control and PEO-modified poly-1 nanoparticles was internalized in BT-20 cells. Results of this study demonstrate that PEO-modified poly-1 nanoparticles could provide increased therapeutic benefit by delivering the encapsulated drug to solid tumors.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, Northeastern University, 110 Mugar Life Sciences Building, Boston, MA 02115, USA.
authors.forename: Anupama
authors.initials: A
authors.lastname: Potineni
authors.forename: David M
authors.initials: DM
authors.lastname: Lynn
authors.forename: Robert
authors.initials: R
authors.lastname: Langer
authors.forename: Mansoor M
authors.initials: MM
authors.lastname: Amiji
mesh_terms: D016503:Drug Delivery Systems / Q000379:methods*; D004952:Esters / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008863:Microspheres; D036103:Nanotechnology / Q000379:methods*; D017239:Paclitaxel / Q000008:administration & dosage* / Q000737:chemistry; D010316:Particle Size; D011092:Polyethylene Glycols / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism
chemical_list: D004952:Esters; D011092:Polyethylene Glycols; D017239:Paclitaxel