The US FDA has issued guidance for liposome drug products. The norms highlight the submissions for a new drug application (NDA) or abbreviated new drug application (ANDA) for a liposome product. A liposome is a tiny bubble (vesicle), made out of the same material as a cell membrane. Liposomes can be filled with drugs, and used to deliver drugs for cancer and other diseases
 
The recommendations in this guidance focus on the technical aspects of liposome drug products. But his guidance does not provide suggestions on clinical efficacy and safety studies of drug-lipid complexes. There is need to provide drug product specification that accounts for specific attributes for your liposome products.
 
Liposomes are composed concentric series of multiple bi-layers which are separated by aqueous compartments formed by amphipathic molecules such as phospholipids. In a liposome product, the drug substance is generally contained in liposomes. Typically, water soluble drugs are contained in the aqueous compartment and hydrophobic drugs are contained in the lipid bi-layers of the liposomes.
 
We recommend expressing the composition of the drug product as milligram of drug substance per milliliter of drug product and also milligram of drug substance per vial for liquid drug products. For dry powders, only the total amount of the drug should be listed, stated the guidance.
 
Going by its pharmacological and toxicological properties the quality of a liposome product can vary significantly with changes in the formulation. Therefore the liposome structure and integrity are important physicochemical properties because it reflects the ability of the liposome drug formulation.
 
The properties useful to characterize a liposome drug formulation are morphology, surface characteristics and drug product viscosity. Besides drug encapsulation efficiency drug loading information should be supported by development data, including test results on batches of liposome drug used in pivotal clinical trials or bioequivalence studies, stated the guidance.
 
According to industry experts the need for a guidance is critical as liposome drug products are used in the treatment of cancer among other diseases. Therefore there is need to closely monitor the leakage rate of drug from the liposomes throughout shelf life. In addition, liposome integrity changes in factors such as salt concentration, pH, temperature, or addition of other excipients, need to be monitored.