Intraductal injection as an effective drug delivery route in the management of salivary gland diseases

While conservative approaches for chronic sialoadenitis are in current use, the utility of intraductal injection therapy remains unclear. The purpose of this study is to provide evidence that substances delivered through intraductal injection of the salivary gland are able to be effectively distributed throughout the gland. Methylene blue dye (0.1 %) was injected intraductally into a porcine parotid gland (5 ml) of one group and the porcine submandibular gland (1 or 2 ml, n = 6 for each preparation) of another group. After the injection, the ductal systems were evaluated, sectioned, and observed microscopically. Color area analysis was performed on submandibular gland sections, and the infiltration ratio of the dye was calculated. The papillae of both Stensen’s and Wharton’s duct openings were easily identified with intraductally delivered methylene blue dye. The dye infiltration began from the central ductal region of the gland and could be easily observed to gradually disperse to the peripheral regions in each acinar. There were no statistically significant differences in infiltration ratios between anterior, midline, and posterior section of the submandibular gland. Also, there were no statistically significant differences in the ratios between 1 and 2 ml injections at all the three section positions. This study demonstrated that desired substances can be evenly delivered throughout the salivary gland through intraductal injections. The use of intraductal injections might serve as a potential therapeutic procedure in the management of salivary gland diseases.