Synergistic antibacterial effect of highly permeable curcumin and ciprofloxacin containing self-emulsifying drug delivery system against urinary tract bacterial infections

Antibacterial properties of curcumin (Cur) and ciprofloxacin (Cip) against urinary tract bacterial infections can be improved by using self-emulsifying drug delivery system (SEDDS). Previously prepared Cur-SEDDS (lauroglycol FCC, tween 80, transcutol HP) alone and its combination with ciprofloxacin (Cip) were used to investigate the antibacterial activity against Staphylococcus aureus , Escherichia coli and Pseudomonas aeruginosa. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), dose response curve, checkerboard assay and time kill assay were performed to investigate the synergistic effect of Cur and Cip. FTIR, polydispersity index (PDI), zeta potential, permeability coefficient (K p ), cell viability assay of Cur, Cip and Cur-Cip containing SEDDS were performed. Average PDI of all SEDDS was 0.3±0.97 with negative charge -10.56±0.67mV at pH 6.8 and encapsulation efficiency 93.88%. Interestingly, Cur and Cip showed synergistic behavior at average MIC of 72±0.45 and 0.33±0.98 against three microorganisms. Stability analysis using Rgui software (R 4.1.3 version) estimates shelf life of 16 months. Improvement in the permeation rate was up to 10 times of Cur and 3 times of Cip in case of SEDDS as compared to their pure form. Enhanced permeation through SEDDS and synergistic antibacterial effect will help in establishing its therapeutic usefulness especially for bacterial urinary tract infections in humans.