Intranasal Corticosteroids: Topical Potency, Systemic Activity and Therapeutic Index

Area of Science:

• Pharmacology
• Allergology
• Drug Development

Background:

• Intranasal corticosteroids (INCS) are preferred for allergic rhinitis (AR).
• Differences in INCS properties may affect clinical outcomes.
• Systemic exposure and adverse events in children are generally low.

Purpose of the Study:

• Assess the therapeutic relevance of INCS topical potency.
• Evaluate physicochemical and pharmacokinetic properties of INCSs.
• Examine the relationship between topical potency and therapeutic index.

Main Methods:

• Narrative review of INCS pharmacological features.
• Analysis of glucocorticoid receptor (GR) binding affinity.
• Comparison of lipophilicity, nasal retention, and bioavailability.

Main Results:

• Higher GR binding affinity correlates with increased lipophilicity, nasal retention, and topical potency.
• Higher topical potency is linked to lower oral bioavailability and systemic exposure.
• Clinical studies often show no significant differences between INCSs, despite varying potencies.

Conclusions:

• Higher GR binding affinity and topical potency may enhance an INCS's therapeutic index.
• Consider both efficacy and systemic exposure for therapeutic equivalence.
• Avoid assuming all INCS formulations are identical for clinical decision-making.