Nasal Drug Delivery Challenges
Despite easy access, the complex geometry of the nose makes reliable and efficient delivery of drugs to the mucosal surfaces challenging. The nasal valve is the narrowest segment of the respiratory tract, accounting for up to 80 percent of nasal resistance and almost half of total respiratory resistance. Sniffing causes additional narrowing of the elastic tissues of the valve.
Traditional spray pumps deliver a dose of medication primarily to the anterior segment of the nasal passage, which is lined with skin-like epithelial cells. Effective, targeted drug delivery requires drug to be delivered beyond the nasal valve to the mucosal surfaces that are lined by a single cell-thick columnar epithelium.
OptiNose Device Overcomes Traditional Spray Pump Challenges
The nasal valve area, located two to three centimeters into the nose, limits the percentage of particles that are able to penetrate further. The high velocity of the particles leaving a traditional spray pump also causes the larger particles, in particular, to hit the valve rather than float through and around the obstructing structures. In addition, the relatively wide plume angle of the mist leaving the nozzle may also reduce the distance the drug particles travel and cause drug to simply impact the sides of the nose before even reaching the nasal valve. Using a pressurized device to try and force drug in “harder” may simply exacerbate this problem.
Given the amount of spray delivered close to the nasal opening, it is not surprising that a considerable portion of the total drug dose is deposited in this region where it may drip and be wiped away, or eventually be blown out of the nose. The percentage that is transported toward the back of the nasal cavity has been shown to be mainly cleared along the floor of the nose, limiting its exposure to the entirety of the mucosal surface area where interchange with the cells and circulation takes place. Additionally, sniffing, which is recommended with many nasal sprays or that frequently takes place naturally to avoid drips, can cause a large part of the dose to be drawn rapidly into the throat where it is lost to swallowing.
OptiNose’s Bi-DirectionalTM Breath Powered® Exhalation Delivery Systems have the potential to reliably and effectively deliver drugs and vaccines deep into the nasal cavity, to overcome these challenges and enable the improved treatment of both local and systemic diseases.