**8. Recent technologies for preparation of liposomes**

Different liposome technologies developed for preparation of liposome formulations. All these technologies have their unique characteristics with unique properties for drug delivery.

#### **8.1 Stealth liposomal technology**

In stealth liposomal technology method some strands of polymer are attached to drug molecule for safety to that therapeutic agents. In PEGylation process polyethylene glycol is used. Linkage of PEG to liposomes protects drug molecules in physiochemical properties along with changes in hydrodynamic size and prolongs circulatory time. PEGylation reduces frequency of dosage and provides hydrophilic nature for hydrophobic drugs. Drug efficacy will not be changed by this method and also shows reduced toxicity [68]. With the help of this technology a liposomebased formulation Doxil® which is intravenous injection was prepared for ovarian cancer, multiple myeloma, and Kaposi's sarcoma associated with HIV.

#### **8.2 Non-PEGylated liposomal technology**

Non-PEGylated liposome technology (NPLT) is another technology for liposomes delivery in cancer treatment which has more benefits compared to PEGylation process. This technology eliminates PEG side effects and hand foot syndrome (HFS) in chemotherapy treatment. Non-PEGylated liposome Doxorubicin (NPLD) decreases cardiac toxicity related with DOX and dose limiting toxicity with Doxil® like painful HFS [69]. Myocet® is another NPLD used in advanced stage IV breast cancer which was manufactured by company Elan Pharmaceuticals.

#### **8.3 DepoFoam™ liposome technology**

This technology was invented by Pacira Pharmaceuticals for preparation of multivesicular liposomes without changing molecular structure of encapsulated drug and releases drug for long period (1 to 30 days). DepoFoam® is a core technology for liposomal marketed products in names Depocyt(e)® containing cytarabine, DepoDur® contains morphine sulfate and Exparel® contains

bupivacaine. These formed vesicles are microscopic spheroids with 3–30 μm in size having granular structure with single layered lipid molecules composed like honeycomb and drug molecules are loaded in central aqueous core [70].
