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University of Tehran
Preparation of Magnetic Drug-Loaded PLGA Nanospheres as
Biodegradable Magneto-Responsive Drug Carriers
Mohsen Ashjari1, Sepideh Khoee 2, Ali Reza Mahdavian *,1
1
2
Polymer Science Department, Iran Polymer and Petrochemical Institute, Tehran, Iran
Polymer Chemistry Department, School of Science, University of Tehran, Tehran, Iran
E-Mail: [email protected]
Abstract
The aim of this study is preparation of drug-loaded
biodegradable magnetic PLGA nanospheres made
by emulsification - evaporation method. The
encapsulation procedure involves the formation of
oil-in-water emulsion in which consists of an oil
phase containing magnetite nanoparticles in an
aqueous solution of drug, emulsification in an oil
phase containing PLGA and a stabilizer and lastly
emulsification double emulsion in an aqueous PVA
solution lead to formation final multiple emulsion.
The mean diameters of the magnetic PLGA
nanospheres in this study were smaller than the
critical size required for the recognition by the
reticuloendothelial system (RES). The morphology
and size distributions of the prepared magnetic
PLGA nanospheres were investigated by SEM. The
micrographs showed that the magnetic nanospheres
were almost spherical in shape and the mean
diameter within the range of 100-300 nm with broad
size distributions.
Introduction
In order to avoid the inconvenient surgical insertion
of large implants, injectable biodegradable and
biocompatible polymeric particles (microspheres,
microcapsules, nanocapsules and nanospheres)
could be employed for controlled-release dosage
forms [1]. Intravenous (i.v.) administration of drugs
leads to systemic distribution throughout the body
resulting in undesirable side effects and as a
consequence only a suboptimal dosage of drugs
reaches the desired target site. Magnetic nanodevice
for
targeted
delivery
approach
involves
administration of a therapeutic agent bound or
encapsulated in a magnetic carrier [2]. These
magnetic nanodevices that have unique surface
properties permitting maximum biocompatibility
and biodegradability could be suitable for drug
delivery vehicles. Such systems can be driven and
held in the specific area for a desired period of time
by applying external localized magnetic fields.
Additional advantages of this drug delivery by
magnetic targeting include the maintenance of drug
levels within a desired range by reducing their
systemic distribution and the possibility of
administering lower but more accurately targeted
doses of the cytotoxic compounds used in these
treatments [3, 4].
Experimental part
In brief, magnetite nanoparticles were dispersed in
DCM. Next, the inner aqueous solution was
prepared by dissolving 5-flourouracil as a
hydrophilic drug in water. lsion.
Experimental
Then, this double emulsion was poured into an
aqueous PVA solution and the mixture was
ultrasonicated. The resulting emulsions were diluted
in PVA solution under mechanical stirring and the
DCM was eliminated by solvent evaporation. The
resulting magnetic PLGA nanospheres were
cleaneresuspending d by repeating procedure of
centrifuging and in distilled water for three times
and then were collected by a magnet.
Results
The presence of PLGA causes such a decrease in
Ms of the magnetic PLGA nanospheres relative to
the pristine magnetite nanoparticles. On the other
hand, it is well known that magnetic particles less
than 30nm will demonstrate the characteristic of
superparamagnetism, which can be verified by the
magnetization curve. behavior.
Results
The FTIR spectrum of freeze-dried magnetic
PLGA nanosphere was obtained by the KBr pellet
method. The FTIR spectrum shows the presence of
all bands of the PLGA (ester carbonyl C=O stretch
band at 1756 cm-1, strong), 1171 & 1090 (C-O-C in
ester group, strong), 2850–3010, 1360–1460
(saturated C-H, including CH3, CH2, and CH),
3500 (terminal OH, weak), a peak at 1660 cm-1
that is attributed to 5-FU and a peak at 580 cm-1
that represents the existence of magnetite
nanoparticles.
Scanning electron microscopy (SEM) is powerful
tools to characterize size, morphology and
structure of magnetic PLGA nanospheres. The
prepared samples were observed by SEM to obtain
information about the morphology and surface
characterization (shape, distribution, aggregation)
of the magnetite PLGA nanospheres. be identified
in certain areas of some nanospheres.
Figure 2: Magnetization vs. applied magnetic field for
magnetite nanoparticles and magnetic PLGA
nanospheres.
Conclusion
Magnetic drug targeting employing nanospheres as
carriers is a promising cancer treatment avoiding
side effects of conventional chemotherapy. This
study suggests that the modified multiple emulsion solvent evaporation process is a prospective
technique to prepare biodegradable magnetic
nanospheres containing water-soluble sensitive
agents. microspheres or nanospheres.
Acknowledgements
The financial support of Iran National Science
Foundation is greatly acknowledged.
SEM micrograph of the magnetic PLGA nanospheres.
References
To investigate the magnetic properties of magnetite
nanoparticles and drug-loaded magnetic PLGA
nanospheres, VSM measurement was used. Figure 2
shows the magnetization curve of the prepared
magnetite nanoparticles and drug-loaded magnetic
PLGA nanospheres.
[1] R. Jalil, J.R. Nixon: J. Microencapsulation, 7 (1990)
297.
[2] S.H. Hu, K.T. Kuo, W.L. Tung, D.M. Liu, S.Y. Chen,
Adv. Func. Mater. 19, (2009) 3396.
[3] S. Goodwin, C. Peterson, C. Hoh, C. Bittner, J. Magn.
Magn. Mater. 194, (1999) 132.