Exploring the possible targeting strategies of liposomes against methicillin-resistant Staphylococcus aureus (MRSA).

Multi antibiotic-resistant bacterial infections are on the rise due to the overuse of antibiotics. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the pathogens listed under the category of serious threats where vancomycin remains the mainstay treatment despite the availability of various antibacterial agents. Recently, decreased susceptibility to vancomycin from clinical isolates of MRSA has been reported and has drawn worldwide attention as it is often difficult to overcome and leads to increased medical costs, mortality, and longer hospital stays. Development of antibiotic delivery systems is often necessary to improve bioavailability and biodistribution, in order to reduce antibiotic resistance and increase the lifespan of antibiotics. Liposome entrapment has been used as a method to allow higher drug dosing apart from reducing toxicity associated with drugs. The surface of the liposomes can also be designed and enhanced with drug-release properties, active targeting, and stealth effects to prevent recognition by the mononuclear phagocyte system, thus enhancing its circulation time. The present review aimed to highlight the possible targeting strategies of liposomes against MRSA bacteremia systemically while investigating the magnitude of this effect on the minimum inhibitory concentration level.

Stabilising cubosomes with Tween 80 as a step towards targeting lipid nanocarriers to the blood-brain barrier.

Coating nanoparticles with the surfactant Tween 80 have been previously shown to enhance drug delivery across the blood-brain barrier (BBB). The aim of this study was to investigate whether Tween 80 could be used to stabilise phytantriol-based cubosomes thereby enabling potential application in delivering macromolecular therapeutics to the brain. Cubosome particles with their large internal and external surface area by virtue of their nanostructure are ideal for delivery of macromolecules. Phase behaviour studies were conducted using a combination of optical microscopy and small-angle X-ray scattering (SAXS) and the addition of Tween 80 to mixtures of phytantriol and water resulted in a rich array of lyotropic mesophases. In particular, a large cubic phase region and a two-phase region of readily dispersed cubosomes is observed. Cubosomes with different concentrations of Tween 80 and phytantriol as the liquid crystal forming lipid were prepared using the solvent precursor method and their physical properties were investigated. A combination of dynamic light scattering, cryogenic electron tomography and SAXS shows formation of well-defined cubosomes with a narrow size distribution and the Im3m cubic structure. Collectively, the results confirm that Tween 80 can effectively stabilize phytantriol cubosomes, opening the possibility for future application in drug delivery across the BBB. Moreover, well-defined, homogenous cubosome formulations prepared using the mild solvent precursor dilution method has significant implications for large-scale production of cubosomes, which currently is a major barrier to the application of cubosomes in the clinic.