Proliposomes for Nasal Delivery
Nasal delivery is a useful delivery route in vaccination. The nose is the first point of contact with inhaled pathogens, rich in lymphoid tissue and has a relatively large surface area through which uptake of antigenic material can take place.
This route is easy to access and eliminates the use of needles. Both systemic and mucosal immunity can be achieved following nasal vaccination in animal and man. Liposomes are made of layers of phospholipids very similar to the phospholipids that make up cellular membranes. Since their discovery, liposomes have attracted much interest due to their structure, chemical composition, colloidal size, amphiphilic properties and biological characteristics. The commercial success of liposome technology is limited due to the hydrolysis, oxidative degradation of phospholipids and fusion of the vesicles on prolonged storage.
Proliposomal systems and their potential in nasal vaccination are being investigated. Proliposomes are stable phospholipid formulations that generate liposomes upon addition of aqueous phase. Ethanol-based proliposomes are concentrated ethanolic solutions of phospholipids. The potential of this technology for nasal delivery of protein and immunoactive molecules has been investigated. Other liposome derivatives such as niosomes and cochleates are also being investigated as carriers of antiasthma drugs. Cochleates have potential in encapsulating and delivery of small molecules of various hydrophobic drugs such as, amphotericin B, to treat fungal infections, and protein vaccines to amplify immune responses.