Challenges of liposomes include:

• Liposomes can be unstable, resulting in a short shelf life. 
• Some drugs can leak out of the liposome before it reaches the intended target. 
• Achieving consistent drug loading efficiency can be difficult, which can skew the results. 
• Production of liposomes is complex and expensive, involving intricate procedures and specialized equipment. 
• Liposomes can be rapidly taken up and cleared by the reticuloendothelial system (RES), especially if not designed to avoid detection.