Histamine-induced intraperitoneal vascular permeability assay
To evaluate the changes of intraperitoneal vascular permeability induced by histamine, Evans blue dye was used as an
indicator according to the method previously described by Whittle [13]. Rats were injected intravenously with 5 mL/kg
of 1% Evans blue solution 60 min after the oral administration of AEBO, vehicle, or loratadine. Rats were killed 30 min after the intraperitoneal injection of histamine. The concentration of Evans blue in the peritoneal fluid was measured via spectrophotometry at 610 nm wavelength.