The Application of Self-Assembling Nanoemulsion (Sane) in the Delivery of the Antibiotic Cefazolin

Antimicrobial resistance is an important health issue. Recent developments in nanotechnology have made possible opportunities to develop novel delivery options for pharmaceuticals and other biological agents already on the market today. In this study, an oil-in-water nanoemulsion and an aqueous solution of Cefazolin at 30 ug/mL and serial dilutions thereof, were tested against a quality control strain of Staphylococcus aureus (S. aureus). A S. aureus bacterial suspension was streaked on to nutrient agar (NA) plates. Cefazolin preparations were added to wells aseptically bored out at 5 drops/well. The observed inhibitory zones were measured in millimeters. Our results demonstrated that the Cefazolin nanoemulsion formulation and Cefazolin aqueous solution at 30 ug/mL produced an inhibitory effect of 23 and 24 mm respectively. Quantitative plate counts of the Cefazolin preparations were also evaluated. Serial dilutions of both Cefazolin preparations were made in a 96- well microtiter plate using Mueller Hinton Broth (MHB). A suspension of Staphylococcus aureus equal to 1.0 x 107, was added to the wells and this plate was incubated at 37 C for 16-18 hr. Post incubation, the wells were subbed to NA plates and examined for CFU/mL. The NA plates containing the Cefazolin nanoemulsion formulation produced a decreased CFU/mL compared to the Cefazolin aqueous solution. Accordingly, the results of this study suggest that by decreasing the concentration of an antibiotic by its incorporation into a nanoemulsion formulation, we may reduce the amount of antibiotic needed to be delivered to produce both an inhibitory effect and a decrease in CFU/mL, thus reducing the potential for increased incidence of antibiotic resistant infections.