Gradient Solvent Replacement-Mediated Formation of High-Strength Hydrogel-Forming Microneedle for Long-Term Drug...

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Nanotechnology

Background:

• Microneedles offer minimally invasive transdermal drug delivery.
• Hydrogel-forming microneedles (HFMs) have high drug loading and biocompatibility but require drying, which can affect drug activity and increase costs.

Purpose of the Study:

• To develop a high-strength, pH-responsive hydrogel-forming microneedle (HFM) patch for post-drug loading and long-term transdermal delivery.
• To enhance the mechanical properties of HFMs in a hydrated state for improved epidermal penetration.

Main Methods:

• Developed a novel HFM patch using an acrylonitrile-acrylic acid copolymer.
• Utilized gradient solvent replacement to create dipole-dipole and hydrogen bonding interactions within the cross-linked network, enhancing mechanical strength.
• Characterized the hydrogel's tensile strength, Young's modulus, and the microneedles' mechanical force.

Main Results:

• The developed hydrogel exhibited a tensile strength of 26 MPa and a Young's modulus of 407 MPa.
• The microneedles demonstrated a single needle mechanical force of 1.18 N, indicating high strength in the hydrated state.
• The pH-responsive design enabled post-drug loading and facilitated long-term drug release upon skin contact.

Conclusions:

• The high-strength, pH-responsive HFM patch overcomes the limitations of traditional HFMs by maintaining mechanical integrity in a hydrated state.
• This advanced HFM platform shows significant promise for efficient and sustained transdermal drug delivery.
• The developed microneedle technology offers a viable alternative for minimally invasive drug delivery applications.