The synthesis and characterisation of novel ultra-flexible lipidic vesicles using propanol

Abstract

There is a large population of microorganisms which reside deep within the skin and are not easily accessible or removed without damaging the skin layers. Therefore, it
would be useful to design an effective drug delivery system that could deliver the antimicrobial agent deeper into the outmost layer of the skin, the stratum corneum.
The main objective of this study was to prepare a nanosized lipidic particulate drug delivery system that has an innate antimicrobial activity as well as the ability to carry an antimicrobial agent with the potential to deliver the drug through the skin. Similar to ethosomes and transfersomes, the use of edge activators such as sodium cholate hydrate, Span 80 and Tween 80, could make these lipidic nanoparticles more elastic and have the ability to be deformed allowing deeper penetration into the skin or applied topically.
In this study, thin film hydration technique was used to prepare the conventional formulations of liposomes, ethosomes and transfersomes by first dissolving DPPC, SPC, cholesterol and edge activators (Sodium cholate hydrate, Span 80, Tween 80) in either chloroform or chloroform: methanol mixture. The samples were then hydrated by a PBS (pH 7.4), doubled distilled water or distilled water-ethanol mixture following rotary evaporation for 60 minutes. The conventional formulations either with or without the model drug (chlorhexidine) were compared with the purposely- designed ultraflexible lipidic formulation, which is termed as propanosomes.
Modifying the thin film hydration method, this study used propanol for the hydration step for the synthesis and optimisation of propanosomes.
Propanol was selected over other solvents due to its more bactericidal property.
All formulations were characterised using laser diffraction, zeta sizer and lipid extrusion techniques. The propanosomal formulations were visualised under TEM. The following size ranges were found with the following formulations: liposomes (1μm), ethosomes (6-8 μm), transferosomes (60-90 nm) and propanosomes (80-100 nm). These experiments alsoshowed that ethosomes were more ultradeformable than liposomes and transfersomes as there was no change of the size upon extrusion. The propanosomal results showed that the mean particle size was inherited by transfersomes and deformability and charge were inherited by ethosomes concluding that the combining preparatory method of using transfersomes and ethosomes was successfully achieved.
Antimicrobial studies on the formulations as disk diffusion testing was also conducted on the formulations. In conclusion, the results of this study have demonstrated that it is possible to synthesis and characterise novel lipidic particulate system and further optimisation on the nanolipidic system warrants potential application as drug delivery system for topical antimicrobial application.