Macromolecular delivery into skin using a hollow microneedle

Area of Science:

• Biomedical Engineering
• Pharmaceutical Sciences
• Dermatology

Background:

• Transdermal drug delivery offers a minimally invasive alternative to traditional administration routes.
• Efficient delivery of large, hydrophilic molecules via the skin remains a significant challenge.
• Microneedle technology presents a promising approach to overcome the skin's barrier function.

Purpose of the Study:

• To investigate the efficacy of hollow microneedle array-patch systems for transdermal delivery of large molecular compounds.
• To determine the influence of various parameters on drug release kinetics from the skin.
• To gather data for the development of effective hollow microneedle delivery devices.

Main Methods:

• Utilized hollow microneedles to deliver fluorescein isothiocyanate (FITC)-dextran (FD-4, 4.3 kDa) into the skin of hairless rats.
• Investigated the effect of injected solution volume and multiple injections on FD-4 release rate.
• Analyzed drug release profiles using Fick's law of diffusion and compared release rates for compounds of varying molecular weights.

Main Results:

• Hollow microneedles successfully delivered FD-4 into the lower epidermis and superficial dermis.
• Increased injection volume and divided administration (multiple injections) accelerated FD-4 release.
• Larger molecular size of model compounds resulted in a slower release rate from the skin.
• Drug release profiles were predictable and could be controlled through formulation and microneedle parameters.

Conclusions:

• Hollow microneedle array-patch systems are effective for enhancing the transdermal delivery of large, hydrophilic molecules.
• Parameters such as injection volume, administration frequency, and molecular size significantly impact drug release kinetics.
• This study provides valuable insights for designing optimized hollow microneedle systems for advanced transdermal drug delivery.