Liposomal

Liposomal refers to systems that use liposomes as carriers. A liposome is a spherical vesicle composed of one or more phospholipid bilayers that enclose an aqueous core. Liposomes can encapsulate hydrophilic substances in the core and hydrophobic compounds within the bilayer, protecting contents from degradation and altering their distribution in the body. Sizes commonly range from tens to hundreds of nanometers, with surface properties influencing stability and interactions with biological systems.

Liposomes are typically prepared by forming a phospholipid film, hydrating it to create vesicles, and then reducing their size by methods such as sonication, extrusion, or microfluidic techniques. Surface modification, including polyethylene glycol (PEG) coating (PEGylation) or attachment of targeting ligands, can extend circulation time and enable selective delivery to tissues or cells. Liposomes can be composed of various phospholipids and cholesterol to tune stability, permeability, and release characteristics.

In medicine, liposomal formulations are used to improve the delivery and safety of drugs. They are approved for cancer, fungal infections, and eye diseases, among others. Notable products include Doxil (liposomal doxorubicin), AmBisome (liposomal amphotericin B), Myocet (non-pegylated liposomal doxorubicin), and Visudyne (liposomal verteporfin). Beyond therapeutics, liposomes are studied for vaccines, gene therapy, and cosmetic applications where controlled release and enhanced penetration are desired.

Challenges include manufacturing complexity, cost, stability during storage, and variability between batches. While liposomal carriers can improve pharmacokinetics and reduce toxicity for some drugs, benefits are not universal, and formulation-specific risks must be managed through rigorous quality control and clinical evaluation.