Clinical potential of pulsating aerosol for sinus drug delivery

Advancements in acoustic drug delivery for paranasal sinuses: A comprehensive review

Chronic rhinosinusitis (CRS) impacts patients' quality of life and healthcare costs. Traditional methods of drug delivery, such as nasal sprays and irrigation, have limited effectiveness. Acoustic Drug Delivery (ADD) using a nebulizer offers targeted delivery of drug to the sinuses, which may improve the treatment of CRS. This review examines the influence of aerosol particle characteristics, aero-acoustic parameters, inlet flow conditions, and acoustic waves on sinus drug delivery. Key findings reveal that smaller particles improve the ADD efficiency, whereas larger sizes or increased density impair it. The oscillation amplitude of the air plug in the ostium is crucial for the ADD efficiency. Introducing acoustic waves at the NC-sinus system's resonance frequency improves aerosol deposition within sinuses. Future research should address advanced models, optimizing particle characteristics, investigating novel acoustic waveforms, incorporating patient-specific anatomy, and evaluating long-term safety and efficacy. Tackling these challenges, ADD could offer more effective and targeted treatments for sinus-related conditions such as CRS.

The impact of geometrical parameters on acoustically driven drug delivery to maxillary sinuses

Acoustically driven nebulized drug delivery (acoustic aerosol delivery) is the most efficient noninvasive technique for drug delivery to maxillary sinuses (MS). This method is based on the oscillation of the air plug inside the ostium to transport drug particles from the nasal cavity (NC) to the MS. The larger the wavelength of the air plug oscillation in the ostium, the greater the penetration of drug particles to the MS. However, using this technique, the maximum drug delivery efficiency achieved to date is 5%, which means 95% of the aerosolized drugs do not enter the MS and are wasted. Since the largest amplitude of the air plug oscillation occurs at its resonance frequency, to achieve an improved MS drug delivery efficiency, it is important to determine the resonance frequency of the nose-sinus combination accurately. This paper aims to investigate the impact of geometrical parameters on the resonance frequency of the nose-sinus model. Both experimental and computational acoustic models, along with the theoretical analysis, were conducted to determine the resonance frequency of an idealized nose-sinus model. The computational modeling was carried out using computational fluid dynamics (CFD) and finite element analysis (FEA), whereas in the analytical solution, the mathematical relationships developed for a conventional Helmholtz resonator were employed. A series of experiments were also conducted to measure the resonance frequency of a realistic NC-MS combination. The results demonstrated a good agreement between the experimental and CFD modeling, while the FEA and theoretical analysis showed a significant deviation from the experimental data. Also, it was shown that the resonance frequency of the idealized nose-sinus model increases by up to twofold with increasing the ostium diameter from 3 to 9 mm; however, it has an inverse relationship with the ostium length and sinus volume. It was also reported that the resonance frequency of the nose-sinus model is independent of the NC width and MS shape.

The Lung in Primary Immunodeficiencies: New Concepts in Infection and Inflammation

Immunoglobulin replacement therapy (IGRT) has contributed critically to the management of primary antibody deficiencies (PAD) and the decrease in pneumonia rate. However, despite adequate IGRT and improved prognosis, patients with PAD continue to experience recurrent respiratory tract infections, leading to bronchiectasis and continuing decline in lung function with a severe impact on their quality of life. Moreover, non-infectious inflammatory and interstitial lung complications, such as granulomatous-lymphocytic interstitial lung disease, contribute substantially to the overall morbidity of PAD. These conditions develop much more often than appreciated and represent a major therapeutic challenge. Therefore, a regular assessment of the structural and functional condition of the lung and the upper airways with appropriate treatment is required to minimize the deterioration of lung function. This work summarizes the knowledge on lung complications in PAD and discusses the currently available diagnostic tools and treatment options.

Toward smart Nebulization: Engineering acoustic airflow to penetrate maxillary sinuses in chronic rhinosinusitis

Treating chronic rhinosinusitis (CRS) by nebulization requires an airflow capable to deliver medication to deep target sites beyond the nasal valve. Fixed frequency acoustic airflow technology is currently available, mainly as post-surgical therapy, but still have not been able to realize the full potential of direct nose to paranasal sinuses delivery. Reported herein are the application of frequency sweep acoustic airflow and the optimization of its frequency range, sweep cycle duration and intensity. The resonant frequencies of the model's maxillary sinuses can be estimated using the Helmholtz resonator theory. Results indicated a resonant frequency of 479 Hz for the right maxillary sinus and one of 849 Hz for the left maxillary sinus. The highest intrasinus deposition within the experiments are from sweep cycle duration of 1 s, intensity of 80 dB, and frequency range of 100-850 Hz. The optimal range of frequency determined from experiments is in good agreement with the corresponding frequency range obtained from the Helmholtz resonator theory. Results reveal a significantly enhanced maxillary sinus drug deposition. This technique affords the potential of treating CRS.

Intranasal Deposition of Accuspray™ Aerosol in Anatomically Correct Models of 2-, 5-, and 12-Year-Old Children

BACKGROUND

To our knowledge, quantification of intranasal deposition of aerosol generated by Accuspray(™) (AS) in children has never been published. We hypothesized that deposition would vary significantly with age and with placement of the device within, or outside, of the nostril.

METHODS

We tested these hypotheses in anatomically-correct physical models based on CT scans of 2-, 5-, and 12-year-old children with normal, intranasal airways. Models included a removable anterior nose (AN) with exterior facial features and interior nasal vestibule and nasal valve area and a main nasal airway (MNA), subdivided into upper (superior turbinates and olfactory area), middle (middle turbinates), and lower (inferior turbinates and nasopharynx) thirds. Aerosol was generated from distilled water admixed with (99m)technetium pertechnetate and administered during static airflow by AS inserted inside the right nostril (eight runs/model), or outside the right nostril (six runs/model). Mean aerosol Dv(50) ± standard deviation was 67.8 ± 24.7 μm. Deposition was quantified by 2D gamma scintigraphy and expressed as percentage of the emitted dose.

RESULTS

When placed inside the nostril, mean (± standard deviation) deposition within the MNA was significantly less in the 2-year-old, compared to the 5- and 12-year-old, averaging 46.8 ± 33.8% (AN:55.4 ± 29.9%), 75.4 ± 26.7% (AN:23.3 ± 13.6%), and 72.1 ± 18.5% (AN:25.8 ± 18.5%), respectively (p<0.05). When placed outside the nostril, MNA was significantly less in the 2- and 5-year-old compared to the 12-year-old, with 1.4 ± 2.5% (AN:69.7 ± 40.7%), 7.4 ± 9.0% (AN:77.8 ± 32.8%), and 21.1 ± 29.1% (AN:29.2 ± 19.3%), respectively (p<0.05). Deposition in the MNA of all age models was highest when AS was placed inside the nostril (p<0.05). Deposition in the lower third was significantly increased for the 5- and 12-year-old and in the middle third of the 5-year-old when AS was placed inside the nostril.

CONCLUSIONS

These results indicate that age and device placement play important roles in terms of intranasal deposition, when administering aerosol with Accuspray(™) to children.

Assessing sinus aerosol deposition: benefits of SPECT-CT imaging

PURPOSE

Aerosol inhalation therapy is one of the methods to treat rhinosinusitis. However the topical drug delivery to the posterior nose and paranasal sinuses shows only limited efficiency. A precise sinusal targeting remains a main challenge for aerosol treatment of sinus disorders. This paper proposes a comparative study of the nasal deposition patterns of micron and submicron particles using planar gamma-scintigraphy imaging vs. a new 3-dimensional (3D) imaging approach based on SPECT-CT measurements.

METHODS

Radiolabelled nebulizations have been performed on a plastinated model of human nasal cast coupled with a respiratory pump. First, the benefits provided by SPECT-CT imaging were compared with 2D gamma-scintigraphy and radioactive quantification of maxillary sinus lavage as reference for the sonic 2.8 μm aerosol sinusal deposition. Then, the impact on nasal deposition of various airborne particle sizes was assessed.

RESULTS

The 2D methodology overestimates aerosol deposition in the maxillary sinuses by a factor 9 whereas the 3D methodology is in agreement with the maxillary sinus lavage reference methodology. Then with the SPECT-CT approach we highlighted that the higher particle size was mainly deposited in the central nasal cavity contrary to the submicron aerosol particles (33.8 ± 0.6% of total deposition for the 2.8 μm particles vs. 1 ± 0.3% for the 230 nm particles).

CONCLUSION

Benefits of SPECT/CT for the assessment of radiolabelled aerosol deposition in rhinology are clearly demonstrated. This 3D methodology should be preferentially used for scintigraphic imaging of sinusal deposition in Human.

Topical gel therapy for sinonasal polyposis in Samter's triad: preliminary report

OBJECTIVES

Rhinosinusitis and polyposis are difficult to treat in patients with Samter's triad; they commonly recur despite sinus surgery, antibiotics, and/or nasal steroids. The present study assesses the efficacy of a multimodal regimen that includes topical corticosteroids and antibiotics delivered through a hydroxyethyl cellulose gel and by nebulization.

METHODS

Eleven patients with Samter's triad who had polyposis and rhinosinusitis that recurred despite endoscopic sinus surgery were treated with a 6-week course of multimodal topical therapy consisting of a hydroxyethyl cellulose gel that releases corticosteroids and antibiotics, topical nebulization of corticosteroids and antibiotics, saline solution rinses, and sinus debridement. Clinical outcomes were evaluated by Lund-Kennedy endoscopic and symptom scores. Histologic assessment was evaluated by hematoxylin and eosin staining before and after treatment.

RESULTS

Both Lund-Kennedy symptom and endoscopic scores showed.a progressive and statistically significant decline throughout the course of treatment, reaching at 6 weeks 42% of the pretreatment values (p = 0.005) for the Lund-Kennedy symptom score and 34% (p = 0.002) for the endoscopic score, respectively; however, the significance of the improvement was lost with time.

CONCLUSIONS

Topical gel therapy improves clinical symptoms, endoscopic findings, and sinus membrane histologic features in patients with refractory Samter's triad, but the improvement is transient, suggesting that a longer therapeutic period might be needed.