The increased popularity of liposomal delivery systems is found in the pharmaceutical and cosmetics industries for a variety of products that are currently applied to a wide range of applications.
Liposomal technologies provide an innovative alternative for drug development that addresses many issues traditionally associated with protein-based therapies such as efficacy, clinical response and toxicity.
This paper will explore how liposomal delivery systems can be used to improve the current formulations used in these industries while also outlining limitations they may face. Specifically, this paper will focus on formulation optimization, design modifications and current applications of liposomes applied to beauty products, nutraceuticals, immunotherapies and vaccines.
Liposomes were first introduced in the 1960s by Bangham et al. as a novel drug delivery system for antigens and antineoplastics . Since then, numerous studies have been conducted to modify these systems to enhance their performance and prolonged their viability to ultimately maximize the therapeutic efficacy of these drugs.
Liposomes are composed of a phospholipid bilayer surrounded by aqueous solution, mimicking the situation in biological cells. This biocompatible structure will protect encapsulated therapeutics, improving their stability while also providing direct access to the delivery system via endocytosis.
However, liposomes are also extremely sensitive to changes in formulation, which can affect the system’s stability and ultimately the performance of the drug. This sensitivity is due to the relatively large size of these systems (ranging from 100-300 nm), which has been shown to confer limited solubility within aqueous solutions .
As a result, poorly formulated liposomes may have compromised efficacy in delivery due to low encapsulation efficiencies and short circulation times. In addition, liposome stability depends on several factors that include pH, temperature and ionic strength , all of which must be carefully considered when developing a new formulation.
Where stability is concerned, the degradation rates of liposomes are dependent on several parameters including interaction with relevant components in the medium. Liposomal degradation is determined by the loss of membranal integrity over time, resulting in an energetically unfavorable dissolution of liposomes into the surrounding aqueous medium.
Changes in formulation can have a profound effect on the efficacy and safety of liposome-encapsulated therapeutics. The application of these delivery systems to gene therapy has shown to improve the efficiency and viability of these nanoreactor systems. Among other strategies, new deprotection methodology has been employed to enhance liposome performance.