Nasal Administration
Drug delivery via the nasal mucosa, enabling peptide absorption into the systemic circulation while avoiding gastrointestinal degradation. Approved peptide nasal sprays include desmopressin, nafarelin, and calcitonin-salmon. Nasal bioavailability for peptides typically ranges from 1-10%.
Technical Context
The nasal cavity provides approximately 150-180cm² of mucosal surface area with a rich subepithelial capillary network (respiratory region) and direct access to the CNS (olfactory region). Nasal peptide delivery avoids GI degradation and hepatic first-pass metabolism. Limitations include the mucus layer (which traps particles and peptides), mucociliary clearance (removing deposited material within 15-20 minutes), limited volume per nostril (~100-150μL), and enzymatic degradation by nasal proteases. Approved nasal peptide products: desmopressin spray (10μg/spray for diabetes insipidus — bioavailability ~3-5%), nafarelin spray (200μg/spray for endometriosis/precocious puberty — bioavailability ~2-3%), calcitonin-salmon spray (200 IU/spray for osteoporosis — bioavailability ~3%). Absorption enhancers can improve nasal peptide bioavailability.