Liposomes, drug leakage from

An alternative approach to avoid drug leakage from the liposomes on storage is to minimize the volume of the external water phase by... 

Liposomes The pH-sensitive liposomes so developed were able 56 to overcome the three main problems associated with liposomes, i.e., low stability, slow drug release and accumulation In liver/spleen. The ECM targeting liposome could prevent protein adsorption and drug leakage from liposome due to the biotin 2-PEG cross-linker located on interface of liposome. The uptake within the cancer cell is improved and could actively target tumor in tumor ECM to increase tumor accumulation. Also the drug release was enhanced at low pH, thus the potential bioavailability and drug resistance problem are also avoided. 

Liposomes that remain impermeable to their contents cannot release these compounds without interaction with cells. This cellular interaction occurs by three different mechanisms (Fig. 11) [57], Of these, fusion and adsorption usually involve drug leakage, whereas effective drug delivery results from en-docytosis. 

Virosomes are virus-mimicking systems that contain liposomal bilayer and pH-dependent protein impregnated in the liposomal wall. Virosomes are produced by a detergent dialysis procedure. Many researchers have demonstrated that the virosomes facilitate the leakage of the encapsulated drugs from the endosomes into the cytoplasm. This is, however, complicated technology and, so far, no virosome products are used in the clinical practice. 

CF-charged liposomes (25 ig/mL) were incubated for 30 min in the absence or presence of modulators or other agents. Following excitation at 490 nm with a Perkin-Elmer MPF-44B spectrofluorometer, the fluorescence emitted from CF that leaked out of permeabilized liposomes was collected at 520 nm. Values are presented as the average of two experiments. None, indicates that no measurable liposome leakage was observed even when using a drug concentration of 200 pM. 

Self assembly using amphiphilic components to trap drug in solution within a hydrophobic or hydrophilic core has been explored for decades for the delivery of drugs. The most notable example is that of the liposome, which, however, suffered from low entrapment efficiency, leakage, and rapid clearance by the reticuloendothelial system of the liver. This rapid clearance was reduced by the use of PEGylated phospholipids to form of the so-called sterically stabilized or stealth liposomes. ... 

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