A large-volume low-pressure nasal irrigation delivers drug into the nasal cavity? An in vivo study

The nasal administration route emerged as an interesting route in systemic and brain drug delivery, and different modalities of nasal delivery are available. The nasal irrigation is one of them, but there is a lack of studies investigating the distribution of a large-volume irrigation. The main aim of this study was to assess the deposition of radiolabeled saline in the nasal cavities and paranasal sinuses following nasal irrigation by imaging. Five healthy males volunteered to perform large-volume low-pressure nasal irrigation, with a douching device containing 50 mL of radiolabeled isotonic saline. Participants underwent a scintigraphy immediately after. Both the nasal cavities and maxillary sinuses were systematically reached by the solution during nasal irrigation. The sinuses set in a lower position during nasal irrigation showed a tendency to be more irrigated than the sinuses set in a higher position (7.67% vs 22.72%; p = 0.086). Moreover, substantial inter- and intraindividual heterogeneity regarding solution deposition was observed. Large-volume low-pressure nasal irrigation is a good modality to reach the maxillary sinuses as well as the nasal cavities. In order to ensure adequate reaching of both nasal cavities and paranasal sinuses, nasal irrigation should be performed bilaterally.