Extended local anesthesia enabled by flavonoid permeation enhancers

Area of Science:

• Pharmacology
• Biomedical Science
• Pain Management

Background:

• Site 1 sodium channel blockers (S1SCBs) are potent local anesthetics but have short durations of action.
• High doses of S1SCBs can lead to systemic toxicity, limiting their clinical use.
• There is a need for safe and effective methods to prolong the action of local anesthetics.

Purpose of the Study:

• To investigate the potential of flavonoids as chemical permeation enhancers (CPEs) for S1SCBs.
• To evaluate the ability of flavonoids to prolong the nerve block duration of S1SCBs.
• To assess the safety profile of flavonoids as CPEs compared to conventional agents.

Main Methods:

• Tested puerarin (PUE), naringenin, and kaempferol for their effects on S1SCB duration.
• Utilized tympanic membrane (TM) permeation and sciatic nerve fluorescence models to assess drug penetration.
• Coencapsulated tetrodotoxin (TTX) and PUE into liposomes for sustained release studies.

Main Results:

• Flavonoids prolonged S1SCB nerve block duration by 4- to 25-fold.
• Flavonoids demonstrated increased drug penetration across biological barriers (TM, nerve).
• Liposomal coencapsulation of TTX and PUE resulted in anesthesia lasting over 25 days.

Conclusions:

• Flavonoids act as safe and effective chemical permeation enhancers for S1SCBs.
• Flavonoid compounds offer a promising platform for developing long-acting, nonopioid pain therapies.
• Flavonoids represent attractive alternatives to conventional CPEs in various biomedical applications.