Doxorubicin Hydrochloride Liposome (Pegylated) Injections

pegylated liposomal doxorubicin hydrochloride is a A liposome-encapsulated form of the hydrochloride salt of the anthracycline antineoplastic antibiotic doxorubicin. Detailed information such as uses, side-effects, reviews, questions, interactions, and precautions is given here.

Doxorubicin intercalates between base pairs in the DNA helix, thereby preventing DNA replication and ultimately inhibiting protein synthesis. Additionally, doxorubicin inhibits topoisomerase II which results in an increased and stabilized cleavable enzyme-DNA linked complex during DNA replication and subsequently prevents the ligation of the nucleotide strand after double-strand breakage. Doxorubicin also forms oxygen free radicals resulting in cytotoxicity secondary to lipid peroxidation of cell membrane lipids. Liposomal delivery of doxorubicin HCL improves drug penetration into tumors and decreases drug clearance, thereby increasing the duration of therapeutic drug effects; a liposomal formulation of doxorubicin also modulates toxicity, specifically the cardiac effects commonly seen with anthracycline antitumor drugs.
Pegylated liposomal doxorubicin is one of a new class of drug formulations that is delivered in vesicles called liposomes. The doxorubicin molecules in pegylated liposomal doxorubicin are encapsulated in a bilayer sphere of lipids. This vesicle is then surrounded by a dense layer of polyethylene glycol (PEG), hence the name pegylated liposomal doxorubicin. The size of the liposomes, approximately 100 nm, prevents them from entering tissues with tight capillary junctions, such as the heart and gastrointestinal tract, as well as selectively depositing the liposome into the tumor. In contrast to normal vessels, the vessels of the tumor are tortuous, dilated, have morphologically abnormal endothelial cells, and are leaky due to large spaces between pericytes.
These physical characteristics allow more extravasation of the vesicles into the tumor, thus encouraging more deposition of the chemotherapy agent into the tumor. The PEG coating on the liposome creates a hydrophilic layer around the liposome that buffers the liposome wall from the surrounding milieu. This decreases proteins from binding to the lipid bilayer. These proteins act as opsonins, attracting foreign particles that in turn activate the mononuclear phagocytic cells. This leads to break down of the liposome and release of the drug. Therefore, the PEG coating on the liposome increases the longevity of the liposome.