TY - JOUR
T1 - N,O6-partially acetylated chitosan nanoparticles hydrophobically-modified for controlled release of steroids and vitamin E
AU - Quinones, Javier Perez
AU - Gothelf, Kurt Vesterager
AU - Kjems, Jørgen
AU - Caballero, Angeles Maria Heras
AU - Schmidt, Claudia
AU - Covas, Carlos Peniche
PY - 2013/1/2
Y1 - 2013/1/2
N2 - Diosgenin, two synthetic analogs of brassinosteroids, testosterone and dl-α-tocopherol were covalently linked to synthetic water-soluble N,O6-partially acetylated chitosan, for their controlled release. Drug linking was confirmed by FTIR spectroscopy and proton NMR. Conjugates were also characterized by differential scanning calorimetry and wide-angle X-ray diffraction. These conjugates formed self-assembled nanoparticles in aqueous solution with particle sizes ranging from 197 to 358 nm and drug contents between 11.8 and 56.4% (w/w). Spherical 30–60 nm nanoparticles were observed by scanning electron microscopy and transmission electron microscopy upon drying. In vitro release studies performed at acid pH indicated a drug release dependence on substitution degree and particle sizes. Almost constant release rates were observed during the first 6–8 h. Brassinosteroids-modified nanoparticles showed good agrochemical activity in radish seeds bioassay at 10−1 to 10−4 mg mL−1. Tocopheryl-modified nanoparticles exhibited radical scavenging activity in DPPH test.
AB - Diosgenin, two synthetic analogs of brassinosteroids, testosterone and dl-α-tocopherol were covalently linked to synthetic water-soluble N,O6-partially acetylated chitosan, for their controlled release. Drug linking was confirmed by FTIR spectroscopy and proton NMR. Conjugates were also characterized by differential scanning calorimetry and wide-angle X-ray diffraction. These conjugates formed self-assembled nanoparticles in aqueous solution with particle sizes ranging from 197 to 358 nm and drug contents between 11.8 and 56.4% (w/w). Spherical 30–60 nm nanoparticles were observed by scanning electron microscopy and transmission electron microscopy upon drying. In vitro release studies performed at acid pH indicated a drug release dependence on substitution degree and particle sizes. Almost constant release rates were observed during the first 6–8 h. Brassinosteroids-modified nanoparticles showed good agrochemical activity in radish seeds bioassay at 10−1 to 10−4 mg mL−1. Tocopheryl-modified nanoparticles exhibited radical scavenging activity in DPPH test.
KW - Controlled release
KW - Chitosan
KW - Self-assembled nanoparticles
KW - Steroids
KW - Tocopherol
U2 - 10.1016/j.carbpol.2012.07.080
DO - 10.1016/j.carbpol.2012.07.080
M3 - Journal article
C2 - 23044115
SN - 0144-8617
VL - 91
SP - 143
EP - 151
JO - Carbohydrate Polymers
JF - Carbohydrate Polymers
IS - 1
ER -