Related Experiment Video
Updated: May 25, 2026
08:19
Hollow Microneedle-based Sensor for Multiplexed Transdermal Electrochemical Sensing
Published on: June 1, 2012
Dissolving polymeric microneedle arrays for electrically assisted transdermal drug delivery
Martin J Garland1, Ester Caffarel-Salvador, Katarzyna Migalska
1School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, UK
Summary
This study optimized microneedle (MN) geometry for enhanced transdermal drug delivery. Combining MNs with iontophoresis (ITP) significantly improved peptide and protein delivery, showing promise for macromolecule transdermal applications.
Area of Science:
- Biomedical Engineering
- Materials Science
- Pharmaceutical Sciences
Background:
- Microneedles (MNs) and iontophoresis (ITP) are emerging technologies for transdermal drug delivery.
- Combining MNs with ITP offers potential for enhanced drug permeation and precise delivery control.
- No prior studies have investigated ITP with in situ drug-loaded polymeric MN systems or systematically explored MN geometry's impact on performance.
Purpose of the Study:
- To investigate the effect of MN height and density on transdermal delivery of small hydrophilic compounds.
- To evaluate the potential of optimized MN arrays for electrically facilitated delivery of peptide and protein macromolecules.
- To assess the combined effect of MNs and ITP on transdermal delivery of various molecules.
Main Methods:
- Systematic investigation of MN height and density on transdermal delivery of theophylline, methylene blue, and fluorescein sodium across neonatal porcine skin in vitro.
- Evaluation of optimized MN array design (361 MNs/cm², 600 µm height) for delivering bovine insulin and fluorescein isothiocyanate-labeled bovine serum albumin (FTIC-BSA) with and without anodal ITP.
- In vitro permeation studies using neonatal porcine skin model.
Main Results:
- Transdermal delivery extent increased with higher MN height and density.
- The optimal MN design (361 MNs/cm², 600 µm height) maximized transdermal drug delivery for small molecules.
- While MN/ITP did not enhance small molecule delivery, it significantly boosted peptide and protein delivery (e.g., insulin and FTIC-BSA).
Conclusions:
- Optimized soluble polymeric MN arrays show significant potential for transdermal delivery of biomacromolecules.
- The combination of MNs and ITP is particularly effective for enhancing the delivery of peptides and proteins.
- This approach offers a promising one-step strategy for electrically controlled transdermal delivery of macromolecules.
Related Concept Videos
01:18Transdermal Drug Delivery Systems
Transdermal drug delivery systems (TDDS) enable the controlled release of drugs across the skin into systemic circulation. They are particularly advantageous for drugs with short half-lives or narrow therapeutic indices, as they maintain consistent plasma concentrations and reduce the risk of subtherapeutic or toxic levels.TDDS are categorized into monolithic, reservoir, and mixed systems. Monolithic systems embed the drug in a polymer matrix, where diffusion governs release. Reservoir systems...
01:24Site-Targeted Drug Delivery Systems: Polymeric Carriers
Polymeric carriers enhance targeted drug delivery by increasing efficacy while minimizing off-target effects. These carriers comprise a biodegradable polymeric backbone integrated with functional elements that enable targeting, improve physicochemical properties, and regulate drug release.Targeting MechanismsThe targeting ability of polymeric carriers is mediated by a homing device, which is a molecular recognition component designed to selectively bind to specific tissues or cells. Monoclonal...
01:30Modified-Release Drug Delivery Systems: Stimuli-Activated
Stimuli-activated drug delivery systems are designed to release drugs in response to specific physical, chemical, or biological stimuli. These systems often utilize hydrogels—three-dimensional, hydrophilic polymer networks capable of swelling in aqueous environments and retaining significant fluid volumes. Upon exposure to particular stimuli, these hydrogels undergo structural transitions that allow the embedded drug to be released. Due to this adaptive behavior, such systems are also called...
01:27Drug Delivery Systems: Different Types
Conventional oral drug products, termed immediate-release (IR) formulations, are engineered to promptly release their active pharmaceutical ingredient (API) upon ingestion, typically in tablets or capsules. This rapid release often results in swift drug absorption and consequent pharmacodynamic effects, although the timing and intensity can vary depending on the drug's properties. Prodrugs within these formulations require metabolic conversion to activate their pharmacodynamic effects,...
01:19Modified-Release Drug Delivery Systems: Rate-Programmed II
Rate-programmed drug delivery systems release drugs in a controlled manner to maintain therapeutic levels. Three main designs include reservoir, matrix, and hybrid systems.Reservoir systems consist of a drug core enclosed within a membrane that controls drug release. In non-swelling reservoir systems, polymers like ethyl cellulose or polymethacrylates are used. These do not hydrate in aqueous media and control release through membrane thickness, porosity, or insolubility. This type includes...
01:28Parenteral Drug Delivery Systems: Injectables, Implants, and Infusion Devices
Parenteral drug delivery systems play a crucial role in modern therapeutics by enabling the direct administration of drugs into the systemic circulation, bypassing the gastrointestinal tract. These systems are particularly valuable for poorly absorbed oral medications that are unstable in the digestive environment or require rapid onset or sustained therapeutic levels. Delivery is achieved through intravenous, intramuscular, or subcutaneous routes, each selected based on the drug's properties...