Staphylococcus aureus is a common gram-positive bacterium of the human skin microbiota. It is also a dangerous pathogen that can cause serious and even lethal skin
infections. The
topical administration of
metronidazole via nanotechnology-based drug delivery systems, such as liquid crystalline systems, can modulate both the
drug permeation and activity, decreasing its side effects and increasing the
drug potent activity against the gram-positive bacteria. This study aimed at: (1) structurally developing and characterizing a liquid crystalline systems composed of
chitosan and
polyethyleneimine dispersion as the aqueous phase,
oleic acid as the oily phase, and ethoxylated and propoxylated
cetyl alcohol as the
surfactant (FPC) for
metronidazole incorporation (0.5% w/w); (2) evaluating the in vitro release and skin permeation and retention properties of the
metronidazole-loaded liquid crystalline systems (FPC-M); (3) investigating the in vitro antibacterial activity of FPC-M against Staphylococcus aureus. Polarised light microscopy indicated that both FPC and FPC-M are hexagonal systems. Rheological, texture, and bioadhesion assays showed that both are elastic and bioadhesive systems. According to the results of the in vitro release, permeation, and retention assays, FPC can modulate
metronidazole release and allow
metronidazole to stay for a longer time on the skin. The determination of FPC-M activity against Staphylococcus aureus showed that it could target the bacterial cell. In conclusion, the liquid crystalline systems developed in this study can improve the clinical performance of
metronidazole in the treatment of
staphylococcal skin infections.