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Drug Delivery
Published in John G Webster, Minimally Invasive Medical Technology, 2016
Physical means as well as chemical means may enhance transdermal transport. Iontophoresis is a method in which an ionized drug is driven through the skin by means of a small electric current. Iontophoresis has been shown as an effective means to transport charged species, as well as water-soluble neutral species through the skin. Many of the compounds that are difficult to transport through the skin via chemical enhancement transport much more efficiently using iontophoresis. This is primarily because the more difficult species to transport through the skin by means of conventional enhancement are compounds that are charged or polar.
Stimulation of Excitable Tissue and Sensory Stimulators
Published in Leslie A. Geddes, Handbook of Electrical Hazards and Accidents, 1995
Iontophoresis employs a direct current to transport a drug through the skin. Because an electrical field is also present, the transport of water is facilitated, this process being known as electro-osmosis. Iontophoresis transports charged drug molecules; electro-osmosis facilitates the transport of neutrally charged molecules by virtue of enhanced water transport.
Recent advances in nanotechnology based combination drug therapy for skin cancer
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Shweta Kumari, Prabhat Kumar Choudhary, Rahul Shukla, Amirhossein Sahebkar, Prashant Kesharwani
Iontophoresis is a mechanism of electrotherapy used to enhance the permeation of medications across the skin by two principal mechanisms, electrorepulsion and electroosmosis and is generally used for the application of charged ionic molecules across the skin [150]. In this technique of iontophoresis, the two electrodes (cathode and anode) are attached to the skin surface, and a continuous electric current is applied over a solution containing the drug. In the presence of electric field, electromigration and electroosmosis are the main mechanisms of drug transport. This results in a drug iontophoretic flux across the skin, which is the summation of the electroosmosis and electromigration effects. These movements are measured in terms of chemical flux, generally µmol/cm2h.
PVP-microneedle array for drug delivery: mechanical insight, biodegradation, and recent advances
Published in Journal of Biomaterials Science, Polymer Edition, 2023
Keisham Nelson Mangang, Pragati Thakran, Jitu Halder, Kuldeep Singh Yadav, Goutam Ghosh, Deepak Pradhan, Goutam Rath, Vineet Kumar Rai
Among 72 articles, 62 reports are associated with normal PVP-based microneedle, which does not require any stimuli, whereas ten articles are related to near-infrared light, iontophoresis, and geothermal responsive release. Stimuli-responsive microneedle based on polymeric matrices facilitates situation-specific drug release. For the same purpose, various stimuli-responsive materials are used to respond to the change in the surrounding environment (Figure 8). Response mechanisms may include formulation dissociation, matrix degradation, and cleavage from matrices after matrix swelling. Furthermore, these mechanisms help release the payloads in response to an internal signal (pH, glucose, enzyme) and external stimuli (temperature, electric field, light, mechanical stress) [98]. Light-activated microneedles are commonly utilized for chemotherapy and photothermal therapy because they are non-invasive, have a significant spatial resolution, and can be controlled quickly. The spatiotemporal control helps in improving therapeutic efficacy and reducing side effects. The polymeric microneedles may be embedded with photosensitive metal or metal oxide nanoparticles (Au, Pt, and TiO2 nanoparticles) and photochromic agents such as melanin. For making light-activated MNs, the most common and valuable electromagnetic wave can be near-infrared (NIR) radiation. Polymeric MNs that can respond to light exposure are light-activated dissolvable MNs. Diabetic patients can benefit from its minimal risk of hypoglycemia and lack of in vivo toxicities due to the irradiation source controlling drug release and NIR-triggered MNs [98]. Iontophoresis is the process of transferring charged and uncharged molecules into the skin by applying an electric field where electron repulsion and electroosmosis are responsible for drug delivery into or across the skin. The positively charged drugs are repelled from the positively charged anode by electrostatic repulsion. In contrast, electroosmosis is accountable for drug transportation across the skin with the help of water molecules. The combination of iontophoresis and microporation is widely used for various therapeutic applications such as protein, peptide, and small molecule delivery to treat multiple disorders like hypertension, Parkinson’s, inflammatory skin disorders, prostrate cancer, and endometriosis. It enhances drug penetration and flexibility by 24-fold compared to passive permeation and 3-fold compared to microneedle-mediated delivery [89].