Piperine

Initially, the surfactant, cosurfactant and/or co-solvent were added to the bioactive oil at various ratios. The produced mixture was efficiently homogenized and stored in an airtight 3 mL glass vial until use. To isolate the effect of oil type on formulation performance, each bioactive oil was formulated with a fixed amount of cosurfactant (I988) and surfactant (HCO-40) (F1–F4). In addition, the formulations were optimized by varying surfactants and/or cosolvents (Table 6). The prepared SNEDDS were thoroughly investigated using model drugs CUR and PP.

Mice were acclimated for one week. Viable E. coli DH5α resuspended in 0.5 ml of PBS was injected into the peritoneal cavity (i.p.), and the lethal (2×10⁹ CFU) and sub-lethal doses (1×10⁹ CFU) were determined by preliminary experiments, which induced peritonitis or even severe sepsis. Piperine (dissolved in 2% Tween-80 in PBS as a suspension) or vehicle (2% Tween-80 in PBS) was given intragastrically (i.g.) before or after bacterial infection. In the former model, mice were administered with piperine at a dose of 10 or 20 mg/kg once a day for 3 d consecutively prior to bacterial infection (2×10⁹ CFU); in the latter model, mice were infected with bacteria (1×10⁹ CFU) and 1 h later were given with 20 mg/kg piperine for only once. Mouse survival was monitored every 6 h for 4 d. In another experiment, the bacterial burden in the peritoneal cavity of mice was determined. The mice were sacrificed and peritoneal lavage fluids were collected with 1.5 ml PBS. Serial dilutions were made of the lavage fluids and then incubated overnight at 37°C on LB agar plates; CFUs of bacteria were counted and calculated.