Microneedle patch designs to increase dose administered to human subjects.

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Dermatology

Background:

• Microneedle (MN) patches offer potential for drug delivery but are often limited to sub-milligram doses.
• Larger MN patches face challenges in skin application and have limited human acceptability data.
• Optimizing MN patch design is crucial for enhancing dose delivery and patient acceptance.

Purpose of the Study:

• To fabricate and evaluate various large microneedle patch designs for enhanced drug delivery.
• To assess the impact of MN geometric parameters on dose delivery efficiency and skin penetration.
• To determine the human subject acceptability and safety of large MN patches.

Main Methods:

• Fabrication of 18 large MN patch designs using laser microfabrication with varied MN length, number, spacing, and base diameter.
• Manual application of MN patches to human participants.
• Assessment of dose delivery efficiency, total dose, dose per MN, penetration depth, and overall MN delivery efficiency.

Main Results:

• Dose delivery parameters generally improved with decreased MN length, increased MN number (for lengths ≤1000 μm), and increased MN-MN spacing.
• All tested MN patch designs were found to be less painful than a pinprick and generally acceptable to participants.
• MN patches induced mild to moderate transient erythema, with participants preferring them over conventional methods for long-acting contraception.

Conclusions:

• Optimized large microneedle patch designs can significantly enhance drug delivery efficiency and total dose.
• Large MN patches demonstrate high patient acceptability and safety, with minimal discomfort and transient skin reactions.
• Microneedle patch technology shows strong potential for applications like long-acting contraception, warranting further development.