چکیده (انگلیسی):

The purpose of this study was to investigate the effect of particle
size, storage temperature, and duration of storage on the
physical stability and morphology of polylactic-co-glycolic
acid (PLGA) nanospheres and microspheres. PLGA nanospheres
and microspheres containing the fluorescent dye,
Bodipy, were prepared in varying sizes by controlling the
method and degree of agitation during the emulsification
phase of preparation. Mean diameters of the particles were
measured by dynamic light scattering. To evaluate the effect
of storage temperature and duration of storage on the extent
of aggregation, nanospheres and microspheres were stored at
4°C, 25°C, 37°C, and 50°C for 6 days and then monitored
using both confocal and scanning electron microscopy. The
mean ± SD diameters of PLGA particles containing Bodipy
were: 266.9 ± 2.8, 351.6 ± 1.8, 988.8 ± 14.1, and 1865.9 ±
67.0 nm. The extent of aggregation of the particulate delivery
system decreased as the mean diameter increased, and
increased as the storage temperature increased. The maximum
extent of aggregation was observed with the smallest
(266 nm) nanospheres. Microspheres did not aggregate. The
aggregation of nanospheres was significantly reduced by
introducing an additional evaporation step during preparation,
suggesting that migration of residual dichloromethane
from within the nanospheres may have dissolved the PLGA
on the surface. The extent of aggregation of nanospheres
increased as the temperature was increased from 4°C to
50°C, and decreased as particle size increased. To avoid
aggregation, PLGA nanospheres should be stored at 4°C.