Applications of Liposomal Drug Delivery System Technology
Liposomes are a novel drug delivery system (DDS). They are bimolecular
vesicles that form spontaneously when phospholipids are dispersed in water.
Liposomes vary in size, composition and charge and can be used as carriers
for a wide range of drug molecules, such as chemotherapeutic agents,
antimicrobial and antiviral drugs, antiparasitic drugs, genetic material,
vaccines, therapeutic proteins, and anti-inflammatory agents. Liposomal
formulations have unique advantages in both safety and efficacy, so they are
one of the most rapidly developing formulations in recent years. In the past 30
years, research in the field of liposomes has made great progress. Various
types of liposomes, such as liposomes with different particle sizes, the
composition of phospholipids, and suitable additives to meet clinical needs,
have been applied in various therapeutics.
Protect the drug from degradation
The lipids used in the liposomal formulation are sufficiently resistant to
enzymatic degradation to allow the liposomes to protect the encapsulated
drug during circulation. When the liposome enters the cell, the encapsulated
drug is released by membrane diffusion or by lysosomal degradation of the
lipid membrane. Liposomes can also protect their encapsulated drugs in the
gastrointestinal environment and facilitate the gastrointestinal transport of a
variety of substances. Due to their advantages of biodegradability and
non-toxicity, liposomes can be used as vaccine delivery vehicles. The
protective effect of loaded molecules makes liposomes a good candidate
carrier for oral vaccines.
Oral administration
It has been reported that the main factors affecting the stability of oral drugs
include bile, pH values and pancreatic enzymes in the gastrointestinal
environment. Microemulsions are prepared by using liposomes as
suspensions or solubilizers for highly insoluble or lipophilic drugs, and further
made into soft capsules for oral delivery can protect drugs from the
gastrointestinal environment and improve the oral bioavailability of drugs. In
addition, oral administration of liposome-antigen formulations may enhance
antigen delivery to antigen-presenting cells.
Topical drug administration
Liposomes can reduce the side effects of topical drugs because they require
only small doses when used as topical formulations. Furthermore, they
increase the permeability of the skin to the loaded drug. Liposomes are also
important in skincare and cosmetic applications. The enhanced skin transport
of drugs is attributed to the lipid properties of the vesicles as drug carriers.
Pulmonary administration
Many drugs such as peptides and proteins are highly unstable and degrade in
a poor gastrointestinal environment. Pulmonary administration is an ideal
and suitable route of administration for such sensitive drugs. As pulmonary
drug delivery vehicles, liposomal formulations have advantages over
