Sustained-Release Microneedles for Local Delivery of Antibacterial Peptide in Acne Therapy

Area of Science:

• Dermatology
• Biomaterials Science
• Drug Delivery Systems

Background:

• Acne vulgaris is a common inflammatory skin condition with high recurrence rates, often involving Propionibacterium acnes (P. acnes).
• The stratum corneum presents a significant barrier to conventional topical acne treatments, limiting drug efficacy.
• Targeted delivery of antibiotics to pilosebaceous units is crucial for effective acne management.

Purpose of the Study:

• To develop and evaluate a novel detachable, sustained-release microneedle system for localized antibacterial delivery in acne therapy.
• To assess the efficacy of the Bacitracin@Hyaluronic Acid-Zein Microneedle (Bac@HA-ZMN) system in reducing P. acnes-induced inflammation and lesions.

Main Methods:

• Fabrication of a microneedle patch comprising a dissolvable hyaluronic acid base and zein microneedle tips loaded with bacitracin.
• Mechanical testing to evaluate microneedle fracture force and skin insertion depth.
• In vitro transdermal drug release studies and in vivo efficacy assessment in a murine acne model.

Main Results:

• The Bac@HA-ZMN system demonstrated sufficient mechanical strength for skin insertion, delivering bacitracin to approximately 500 μm depth.
• In vitro studies showed significantly higher cumulative bacitracin release (76.1% over 96 h) compared to controls.
• In vivo, the Bac@HA-ZMN treatment significantly reduced lesion area and inflammatory markers (IL-8, MMP-2, TNF-α) in the murine acne model.

Conclusions:

• The Bac@HA-ZMN microneedle system provides an effective platform for localized and sustained delivery of bacitracin.
• This innovative approach shows significant potential for improving acne treatment by directly targeting P. acnes and reducing inflammation.
• The system offers a promising alternative to conventional topical therapies for managing acne vulgaris.