Single Polysaccharide Dissolvable Microneedles for Painless Local Anesthesia: Fabrication, Characterization, and In...

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Dermatology

Background:

• Microneedles (MNs) offer a minimally invasive alternative to conventional drug administration methods.
• Polysaccharide-based MNs present a promising biodegradable platform for transdermal drug delivery.
• Lidocaine is a widely used local anesthetic requiring effective and rapid delivery methods.

Purpose of the Study:

• To develop and characterize single-component pullulan microneedles for transdermal lidocaine delivery.
• To evaluate the mechanical strength, skin penetration, and dissolution properties of the pullulan MNs.
• To assess the safety and efficacy of the pullulan MN-based lidocaine delivery system.

Main Methods:

• Micromolding was used to fabricate pullulan microneedles.
• Mechanical testing assessed needle strength.
• Excised human skin and skin models were used to evaluate stratum corneum penetration and dissolution.
• Cytocompatibility was tested using resazurin metabolic assays on HaCaT, 3T3, and RAW 264.7 cell lines.
• Time-lapse fluorescence microscopy compared lidocaine release efficacy.

Main Results:

• Pullulan microneedles demonstrated high mechanical strength (up to 1.5 N/needle).
• Successful penetration of excised human abdominal skin and dissolution in skin models within 10 minutes.
• Lidocaine retention in the patch was 26% (agarose gel) and 32% (porcine skin) after 10 minutes.
• Over 80% cell viability confirmed cytocompatibility across multiple cell lines.
• MN-delivered lidocaine showed comparable activity to a pure solution on sensory neurons.

Conclusions:

• Dissolvable pullulan microneedles are a safe and effective system for transdermal lidocaine delivery.
• This system offers rapid onset of action (<10 min) and efficient drug release.
• Pullulan MNs represent a promising alternative to conventional local anesthetic administration methods.