Nanotechnology-enabled topical delivery of therapeutics in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the paranasal sinuses which represents a significant health burden due to its widespread prevalence and impact on patients' quality of life. As the molecular pathways driving and sustaining inflammation in CRS become better elucidated, the diversity of treatment options is likely to widen significantly. Nanotechnology offers several tools to enhance the effectiveness of topical therapies, which has been limited by factors such as poor drug retention, mucosal permeation and adhesion, removal by epithelial efflux pumps and the inability to effectively penetrate biofilms. In this review, we highlight the successful application of nanomedicine in the field of CRS therapeutics, discuss current limitations and propose opportunities for future work. Plain language summary: Chronic sinusitis is a common inflammatory condition of the sinuses, which affects patients' quality of life and consumes significant healthcare resources. It is primarily treated with corticosteroids, a type of medication that reduces inflammation, as a nasal spray or taken orally. Nasal sprays are preferred, to minimize side effects elsewhere in the body. Recently, another class of drugs 'biologic agents' - has been approved for a subtype of chronic sinusitis that causes polyps (grape-like swellings of the sinus lining). However, a lasting cure is elusive, because inflammation frequently returns once these medications are stopped. As our understanding of what causes chronic sinusitis improves, researchers are seeking therapies that more accurately target the cause of inflammation, rather than broadly suppressing all types of inflammation using corticosteroids. The use of nanotechnology allows the design of drugs to overcome various challenges in treating chronic sinusitis, potentially enabling more accurate delivery of drugs into the sinuses, improving drugs' ability to remain on the sinus lining and penetrate it, reducing the amount of drug lost due to the action of outflow pumps and overcoming additional defenses built up by bacteria when they form thick films. Here we describe how nanomedicine has been used to develop drugs for chronic sinusitis, discuss current limitations and propose opportunities for future work.