How the Adaptability of Liposomes is helping Overcome Drug Delivery Challenges
18 Oct 2020
The Biopharma Group has reported on recent investigations which indicate liposomes’ potential to be used as a drug carrier – overcoming the problem of low bioavailability.
The study of liposome-drug encapsulation is an expanding field due to their versatility and ease of manipulation in terms of physiochemical and biophysical properties. Conventional liposomes are composed of a lipid bi-layer and liquid core, allowing them to encapsulate hydrophilic and hydrophobic drugs such as Paclitaxel – a chemotherapeutic agent used to treat cancers.
The liposomes are relatively stable at physiological pH, though their contents release under acidic conditions. This has potential in providing targeted anti-cancer therapy, through the lower pH values observed in tumour tissue.
Many formulations of pH-sensitive liposomes are unstable in the blood; overcome by adding polyethylene glycol lipid derivatives to the formulation to produce PEGylated liposomes/stealth liposomes.
Ligand-targeted liposomes offer potential for targeted drug delivery by selectively expressing specific ligands at the site of disease. Theranostic liposome systems encapsulate a nanosized agent such as iron-oxide and gold nanoparticles – which is utilised for imaging. Theranostic liposomes can be PEGylated and ligand-targeted to produce a comprehensive diagnostic and therapeutic drug delivery system.
Overall, adaptability is the key advantage associated with liposomes for drug delivery.
In preparation of the desired liposomes, high pressure homogenisation (HPH), is often performed on pre-formed liposomes to produce small unilamellar vesicles. HPH also has the capability to load liposomes with drugs, allowing for a streamlined process.
Avestin’s range of high pressure homogenisers allow for the combination of homogenisation and extrusion which can reduce the number of cycles required to achieve a desired size distribution, making the process more efficient.