Biomedical Engineering Reference
In-Depth Information
into the particle matrix, covalently bound to surface functional groups, or adsorbed into the particle.
Albumin was well reported to facilitate the endothelial transcytosis of bound constituents princi-
pally through binding to a cell surface glycoprotein receptor (albondin). This glycoprotein binds to
caveolin-1 (an intracellular protein) with the successive formation of transcytotic vesicles (known as
caveolae). Caveolin-1 is often present in some neoplasms (breast, lung, and prostate cancer), which
could explain why albumin is known to accumulate in some tumors and thus facilitates intratumor
accumulation of albumin-bound drugs [125,131]. In addition, the surface modification and introduc-
tion of targeting ligands can be attained with great ease to make the NP target specific (Figures 11.6
and 11.7) [129,130,145,146].
Albumin-bound paclitaxel (Abraxane ® ; Abraxis BioScience and AstraZeneca) is another exam-
ple of an EPR-based nanovector application for breast cancer. It represents one of the strategies
adopted to overcome the solvent-related problems of paclitaxel and it has been recently approved by
the U.S. Food and Drug Administration for pretreated metastatic breast cancer patients. This novel,
albumin-bound formulation of paclitaxel (size 130 nm) is used as a colloidal suspension derived
from the lyophilized formulation of paclitaxel and HSA diluted in saline solution (0.9% NaCl) [132].
Preclinical studies, conducted in athymic mice with human breast cancer, demonstrated that this
product has a higher penetration into tumor cells with an increased antitumor activity compared to
an equal dose of standard paclitaxel [133,134]. Similarly, albumin microspheres also represent an
inimitable class of biodegradable colloidal particles, which have been used for lung scanning and
circulating studies in both animal and human subjects. Bovine serum albumin (BSA) had been suc-
cessfully employed to prepare dry powder formulations for therapeutics [121]. BSA microspheres
loaded with Ciprofloxacin were prepared for lung delivery by a spray drying technique [122]. In
another study, BSA was used to deliver and retain tetrandrine in the lung so as to reduce any anti-
silicotic effects to other organs [135].
In spite of these delivery applications, several investigations related to the toxicity, distribution,
physiological response, and metabolism of the aggregated albumin have been published. Albumin
OH
OH
OH
OH
O
O
O
O
OH
HO
HO
NH
O
O
OH
HO
HO
HO
NH 2
O
NH 2 n
NH 2
O
O
HO
O
O
OH
O
OH
Chitosan
Hyaluronic acid
O
O
O
C
O
C
O
H
O
HO
Gelatin
Dextran
C
C
OH
O
O
n
O
O
C
C
OH H
C
C
O
O
O
O
OH
C
n
O
C
C
(
(
(
O
O
CH 2
O
CH
CH
Y
X
X
H 3 C
H 3 C
C
Poly ( DL -lactide-co-glycolide)
Poly (lactic acid)
O
FIGURE 11.6
Various biomaterials used as gene and drug delivery agents.
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