CLONAZEPAM RELEASE FROM CORE-SHELL TYPE NANOPARTICLES IN-VITRO

AB-type amphiphilic copolymers (abbreviated as LE) composed of poly (L -leucine) (PLL) as the A component and poly (ethylene oxide) (PEO) as the B component were synthesized by the ring-opening polymerization of L-leucine N-carboxy-anhydride initiated by methoxy polyoxyethylene am ine (Me-PEO-NH2) and characterized. Core-shell type nanoparticles were prepared by the diafiltration method. Particle size distribution obta ined by dynamic light scattering was dependent on PLL composition and the size for LE-1, LE-2 and LE-3 was 369.6+/-267, 523.4+/-410 and 561. 2+/-364 nm, respectively. Shapes of the nanoparticles observed by tran smission electron microscope (TEM) were almostly spherical. The critic al micelle concentration (CMC) of the nanoparticles determined by a fl uorescence probe technique was dependent on the composition of hydroph obic PLL, and the CMC for LE-1, LE-2 and LE-3 was 2. 0x10(-6), 1.7x10( -6) and 1.5x10(-6) (mol/l), respectively. Clonazepam release from core -shell type nanoparticles in vitro was dependent on PLL composition an d drug loading content.