Liposomes were discovered by Alec D. Bangham in 1965 (Allen and Cullis 2013) and were the first approved class of therapeutic nano particles for cancer treatment.
Liposomes are bilayer spherical vesicles composed by phospholipids and cholesterol that in water create at least one lipid bilayer surrounding an aqueous core, which may encapsulate both hydrophilic drugs (e.g., Doxil®, encapsulated doxorubicin in the aqueous core) and hydrophobic compounds (e.g., AmBisome®, trapped amphotericin B) immersed in the lamellae by Van der Waals forces (Senapati et al. 2018; Gonda et al. 2019; Gao et al. 2018),
Nano Particle Technology:
Liposomes represent a large proportion of clinical-stage nanotherapeutics (Shi et al. 2017; Bourquin et al. 2018) due to their biodegradable, biocompatible, non-toxic, and non-immunogenic composition (Bozzuto and Molinari 2015; Zamani et al. 2018).
The amphiphilic phospholipid bilayer of liposomes has close resemblance to the mammalian cell membrane, enabling efficient interactions between liposomes and cell membrane and subsequently effective cellular uptake (Gonda et al. 2019).
Since phospholipids are the main biological cell membrane components, both liposomal and cell membranes can coexist during the release mechanism (Rothfield 1971).
Beltrán-Gracia, E., López-Camacho, A., Higuera-Ciapara, I. et al. Nanomedicine review: clinical developments in liposomal applications. Cancer Nano 10, 11 (2019).
In recent years, disease treatment has evolved strategies that require increase in pharmaceutical agent’s efficacy and selectivity while decreasing their toxicity in normal tissues. These requirements have led to the development of nanoscale liposome systems for drug release.
Clinical trials have shown that liposomes are pharmacologically and pharmacokinetically more efficient than drug-alone formulations in treating acute myeloid leukemia, hepatitis A, pain management, ovary, gastric breast and lung cancer, among others.
Liposomal formulations are less toxic than drugs alone and have better pharmacological parameters.
‘Thanks to nanoparticles and liposomes, it has been possible to decrease the toxicity and improve the pharmacokinetics parameters, such as distribution, increased circulation time, targeted controlled release, increased intracellular concentration, and enhanced solubility and stability of drugs in the organism.’ (Medina-Alarcón et al. 2017; Ventola 2017).
‘Advantages have been reached by using drug delivery systems with 1–100 nm diameter nanoparticles, where a large surface leads to an increase in cellular interactions and multiple alterations of surface properties’ (Ud Din et al. 2017; Senapati et al. 2018; Gonda et al. 2019).
In addition, liposomes may be added with ligands to increase efficiency and specifically target damaged cells, thus improving liposome pharmacokinetics and their ability to pass through target membranes, reaching high concentrations inside cells while reducing toxicity and enhancing treatment efficacy (Li et al. 2014; Ud Din et al. 2017; Zamani et al. 2018; Hussain et al. 2017; Lombardo et al. 2016; Fouladi et al. 2017; Maranhão et al. 2017; Miller et al. 2016).
Another advantage of liposomes in their thermosensitive feature, i.e., an increase of temperature (to 40–41 °C) causes packing changes in the bilayer, favoring the release of the encapsulated drug. (Nardecchia et al. 2019).
The results of the clinical studies of liposomal vitamin C by oral delivery: 1.77 times more bioavailable than non-liposomal vitamin C.
Gopi S, Balakrishnan P. Evaluation and clinical comparison studies on liposomal and non-liposomal ascorbic acid (vitamin C) and their enhanced bioavailability. J Liposome Res. 2021 Dec;31(4):356-364. doi: 10.1080/08982104.2020.1820521. Epub 2020 Oct 6. PMID: 32901526.
‘Traditional pharmacological agents have to cross many barriers and hostile environments in the body that degrade them in the way, such as acidic stomach, intestinal wall barrier, liver, proteins, and enzymes in the bloodstream and the blood brain barrier to be able to reach the site where they are needed. Thus, they have to be ingested over and over again to be effective in the body. However, if ingestion exceeds certain doses, the therapeutic agent may become toxic and severely damage one or several organs in the body.
Nanomedicine emerges as a potential solution to these problems, where liposomes are one of the most effective, healthy, and safe nanoparticle structures developed thus far. Liposomes can go through the body and function like a vehicle that can reach the specific tissue, organ or receptor of interest.
Nanomedicine review: clinical developments in liposomal applications
Beltrán-Gracia, E., López-Camacho, A., Higuera-Ciapara, I. et al. Nanomedicine review: clinical developments in liposomal applications. Cancer Nano 10, 11 (2019).
The highly efficient encapsulation properties of such liposomal constructs are proposed to contribute to enhanced vitamin bioavailability.
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