Environmental Engineering Reference
In-Depth Information
DepoCyt (Almac Pharma Services Ltd, Craigavon, UK), a commercially avail-
able liposomal formulation of cytarabine indicated for the treatment of meningeal
neoplasms. The specific multivesicular liposome technology like DepoFoam
(Pacira Pharmaceuticals, Inc.) consists of multiple nonconcentric aqueous cham-
bers within a single bilayer lipid membrane and a foam-like appearance. This
multivesicular liposome has greater drug entrapment efficiency, robust structural
stability with sustained release of the drug for targeting the meninges with least
cytotoxicity [
5
].
9.1.2 Nanoliposomes and Agents Delivered
Encapsulating both hydrophobic and hydrophilic compounds, liposomes serve as
effective platforms for intracellular drug delivery. Liposomes can serve as potent
delivery agent for cancer therapeutics, vaccine, analgesic drugs, and many others.
The triggered release of liposomes can be designed using external stimuli such as
pH, ultrasound, and temperature. Moreover, using different compounds and prep-
aration parameters, the vesicle size, surface properties, and surface charge can be
easily modified. Long-circulating liposomes were prepared by adding polymers like
polyethylene glycol (PEG) to the liposomal surface (PEGylation) to evade the RE
system, longer body stay, and extended release of the encapsulated drug over time.
For diagnostic imaging and targeted therapy, attaching antibodies and other
markers to liposome surfaces serves as better tool [
5
-
7
].
For the safe delivery and entrapment of 5-fluorouracil (5-FU), nanoliposome
carriers composed of endogenously occurring di-palmitoyl phosphatidyl choline
(DPPC), negatively charged dicetyl phosphate (DCP), cholesterol (CHOL), and
glycerol (3 %, v/v) were found to be effective. The release rate of 5-FU was
enhanced by adding high ratio of drug: lipid to the liposomes [
24
].
Imaging of neovasculature is a promising new field in tumor diagnosis. Para-
magnetic nanoliposomes targeted with RGD10, F56, and K237 peptides can bind to
Integrin
3 and VEGFR (vascular endothelial growth factor receptor)-1,
VEGFR-2, respectively, in tumor neovasculature. The imaging was developed as
potential tumor-specific Magnetic Imaging Resonance (MRI) contrast agents for
detecting small tumors in animal models. RGD10 and K237 targeted paramagnetic
nanoliposomes are helpful for tumor detection [
25
].
Hyaluronic acid-modified docetaxel-loaded liposomes (LMWHA-LPs) were
found to significantly increase the docetaxel recovery in lymph nodes, after subcu-
taneous injection site, and plasma, after subcutaneous administration, with longer
retention time compared to unmodified liposomes in vivo. LMWHA-LPs have been
observed to be a highly promising lymphatic targeting carrier for chemotherapeutic
drugs and diagnostic fluorescence agents [
26
].
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