Intranasal Peptide Administration

Intranasal peptide delivery uses a metered-dose spray device. The peptide is reconstituted in bacteriostatic water or saline and loaded into a nasal spray bottle calibrated to deliver a specific volume per actuation (typically 0.1 mL = 100 mcL per spray).

Technique: gently blow the nose to clear mucus. Tilt the head slightly forward (not back — this drains solution into the throat instead of the nasal mucosa). Insert the spray tip into one nostril while gently closing the other. Spray during a gentle inhalation through the nose. Avoid sniffing forcefully — this pulls the solution past the absorptive mucosa into the pharynx. Wait 30 seconds between nostrils.

Absorption occurs primarily through the richly vascularized nasal respiratory epithelium. A secondary pathway — the nose-to-brain route via olfactory and trigeminal nerve endings — may provide partial direct CNS access, bypassing the blood-brain barrier. This route is particularly relevant for Semax, Selank, and oxytocin, where central effects are the therapeutic goal.

Bioavailability varies widely by peptide: 10–80% for small peptides, with molecular weight, charge, and formulation additives (absorption enhancers, mucoadhesive polymers) being key determinants.