Nasal Spray Local Delivery Mechanism
Spray actuation deposits micro-droplets across the nasal mucosal surface.
- ~40 µm: Droplet size (optimized for mucosal deposition)
- <1%: Systemic absorption (largely localized action)
- Turbinates: Contact site (main mucosal surface)
- 50 µg: Dose per spray (typical fluticasone dose)
How the spray reaches tissue
Placeholder: droplets settle on mucosa and are absorbed locally.
Anti-Inflammatory Gene Transcription Effect
Steroid-receptor complex changes expression of inflammatory genes.
- GR-alpha: Receptor type (cytoplasmic glucocorticoid receptor)
- NF-κB inhibition: Key effect (suppresses cytokine genes)
- Hours: Onset of transcription (not immediate)
- IL-4, IL-5: Target cytokines (reduced expression)
Receptor binding to gene effect
Placeholder: receptor complex enters nucleus and shifts gene activity.
Gradual Inflammatory Cell Reduction
Mast cells and eosinophils in mucosa decline slowly with use.
- Eosinophils: Cell types affected (mast cells, basophils)
- Days: Reduction timeline (progressive decline)
- ~7–14 d: Peak reduction (with daily dosing)
- Apoptosis: Mechanism (induced cell turnover)
Cell population over time
Placeholder: inflammatory cell counts fall gradually, not instantly.
Onset Delay — Days, Not Minutes
Unlike decongestants, full steroid benefit takes days to appear.
- Minutes: Decongestant onset (vasoconstriction only)
- 12–48 h: Steroid onset (first improvement)
- 1–2 weeks: Full effect (with daily use)
- PRN use: Common mistake (expecting instant relief)
Why the delay happens
Placeholder: gene-mediated action is inherently slower than vasoconstriction.
Placeholder: patients often stop too early expecting fast relief.
Consistent Daily Use Importance
Regular daily dosing sustains and completes the anti-inflammatory effect.
- Higher: Adherence effect (faster full relief)
- Reset gains: Missed doses (partial reversal)
- Daily, fixed time: Recommended use (not as-needed)
- Favorable: Long-term safety (low systemic exposure)
Why adherence matters
Placeholder: steady daily dosing avoids restarting the delay each time.