Delivery of drugs through the nasal route provides an alternative, yet highly efficacious modality for administering both large and small pharmaceutic molecules. This method proves particularly advantageous for drugs that are unstable during oral administration, as they undergo significant degradation in the gastrointestinal tract or metabolization through the first-pass effect in the liver. Nasal administration stands as a viable alternative to parenteral therapy and is also suitable for long-term medical management. The nasal mucosa, characterized by high vascularity and permeability, facilitates rapid pharmaceutical absorption, ensuring a swift onset of therapeutic action. Despite its noninvasive nature, the nasal delivery technique finds broad applicability for both local treatment and systemic therapy, as the drug directly enters systemic circulation. This article explores the feasibility of a novel spray delivery mechanism for intranasal drug deposition. The study aims to determine whether users can correctly follow the state-of-the-art application instructions for a nasal spray with an optimal nozzle placement angle (namely, 12-15°) at the nostril while maintaining sufficient safety and efficacy, and without engaging in preventable usage errors that could harm the user. Additionally, the study evaluates the effectiveness of device labeling, instructions for use, and a short video in supporting the correct application of the nasal spray at the optimal angle (12-15°) and assesses whether users can differentiate the product from others with similar appearances. We have also performed physical spray tests to experimentally evaluate drug penetration to the nasopharynx (a key target site for viral infections) for two different nozzle placements – one for current package instructions coming with over-the-counter spray products and the other for the optimal spray usage procedure to enhance targeted drug delivery. Human Factors (HF) validation studies were also conducted, instructing users to follow the application instructions of the nasal spray bottle with the nozzle placed at the optimal angle to target the nasopharynx. The experimental tests consistently confirmed improved penetration with the 12-15° nozzle placement, with visual cues proving effective when used in tandem with written instructions for guiding the study participants to adhere to the recommended usage procedures.

This study aimed to determine shifts in microbial populations regarding richness and diversity from daily use of a popular over-the-counter nasal spray. In addition, the finding of nasal commensal bacterial species that overlap with the oral microbiome may prove to be potential probiotics for the “gateway microbiomes.” Nasal swab samples were obtained before and after using the most popular over-the-counter (OTC) nasal spray in 10 participants aged 18–48 years. All participants were healthy volunteers with no significant medical histories. The participants were randomly assigned a number by randomizing software and consisted of five men and five women. The sampling consisted of placing a nasal swab atraumatically into the nasal cavity, which is similar to the sampling performed for COVID-19 testing, with only very slight discomfort, if any. The samples were preserved and sent to Northwestern University Sequencing Center for whole-genome deep sequencing. After 21 days of OTC nasal spray use twice daily, the participants returned for further nasal microbiome sampling. The microbial analysis included all bacteria, archaea, viruses, molds, and yeasts via deep sequencing for species analysis. The Northwestern University Sequencing Center utilized artificial intelligence analysis to determine shifts in species and strains following nasal spray use that resulted in changes in diversity and richness.