Nasal mucosal surfactant film and epithelial surface

The nasal mucosal surfactant film and epithelial surface constitute the primary physical and immunological barrier of the upper respiratory tract [1.3.5]. The surfactant film, composed of phospholipids and surfactant proteins (SP-A, SP-B, and SP-D), reduces surface tension to facilitate mucociliary clearance and provides innate immune defense by opsonizing pathogens [1.1.1, 1.2.1]. The underlying epithelial surface consists of a pseudostratified layer of ciliated, goblet, and basal cells that regulate the transport of ions and water while maintaining a tight barrier against environmental insults [1.4.4]. This complex is a critical site for the initial entry of respiratory viruses, such as SARS-CoV-2, and serves as the primary portal for intranasal drug delivery [1.3.1, 1.3.3]. Therapeutic strategies often target this surface to enhance drug permeation, restore barrier integrity in conditions like rhinitis sicca, or provide a protective shield against allergens [1.1.1, 1.1.2]. For instance, liposomal formulations can stabilize the surfactant layer, while mucoadhesives increase the residence time of drugs on the epithelial surface [1.1.1, 1.3.2]. However, because it is a multi-component physiological structure rather than a single molecule, it is classified as a tissue-level target rather than a traditional pharmacological receptor [1.3.1]. Understanding the interaction between drugs and this surface is essential for optimizing the bioavailability of nasally administered therapeutics [1.3.4]. Safety considerations include the potential for ciliotoxicity or irritation when the barrier is disrupted by chemical enhancers [1.1.2, 1.1.5]. Overall, this surface is a dynamic environment that integrates mechanical, chemical, and biological defenses to protect the respiratory system [1.2.4].

Other names

Nasal lining fluidNasal surfactantNasal epithelial barrierNasal mucosa surface

Drugs interact with the nasal mucosal surfactant film and epithelial surface by modulating surface tension to improve mucociliary clearance, enhancing the physical barrier to prevent pathogen entry, or utilizing mucoadhesive and permeation-enhancing properties to facilitate the absorption of therapeutic agents into the underlying tissue and systemic circulation [1.1.1, 1.3.1, 1.4.1].