Information about Iontophoresis
Iontophoresis is a non-invasive method of propelling high concentrations of a charged substance, normally medication or bioactive-agents, transdermally by repulsive electromotive force using a small electrical charge applied to an iontophoretic chamber containing a similarly charged active agent and its vehicle. To clarify, one or two chambers are filled with a solution containing an active ingredient and its solvent, termed the vehicle. The positively charged chamber, termed the cathode will repel a positively charged chemical, whilst the negatively charged chamber, termed the anode, will repel a negatively charged chemical into the skin.
Iontophoresis is well classified for use in transdermal drug delivery. Unlike transdermal patches, this method relies on active transportation within an electric field. In the presence of an electric field electromigration and electroosmosis are the dominant forces in mass transport. These movements are measured in units of chemical flux, commonly µmol/cm2h. For more information see Fick's Law of Diffusion.
The isoelectric point of the skin is ~4; therefore, under physiological conditions, with the surface of the skin also buffered at or near 7.4, the membrane has a net negative charge and electroosmotic flow is from anode (-) to cathode (+). The phenomenon of electroosmosis has been used as a means to augment the anodic delivery of (in particular) large, positively charged drugs, the transport numbers of which are often extremely small (and whose iontophoretic enhancement therefore depends heavily upon electroosmosis) and to promote the transdermal migration of uncharged, yet polar, molecules, the passive permeation of which is typically very small.
The application of a charge to the skin alters the skin’s permeability increasing migration of the active ingredient into the epidermis. There are a number of pathways that the ingredients could take, but research suggests that the majority of drugs permeate the skin via appendageal pores, including hair follicles and sweat glands, although some delivery is via the paracellular channels and minimal quantities are transcellular.
Transport of lipophilic drug molecules is believed to be facilitated by its dissolution into the lipid matrix of the stratum corneum however hydrophilic drugs which are thought to permeate through the open pores or cutaneous appendages (hair follicle and sebaceous glands) only accounts for 0.1% of the total skin surface area.[1]
Iontophoresis is commonly used by physical therapists for the application of anti-inflammatory medications. Common diagnoses treated with Iontophoresis include plantar fasciitis, bursitis and hyperhidrosis. Iontophoresis of Acetylcholine is used in research as a way to test the health of the endothelium by stimulating endothelium dependent generation of nitric oxide and subsequent microvascular vasodilation. Acetylcholine is positively charged and therefore placed in the anode.
Iontophoresis is well classified for use in transdermal drug delivery. Unlike transdermal patches, this method relies on active transportation within an electric field. In the presence of an electric field electromigration and electroosmosis are the dominant forces in mass transport. These movements are measured in units of chemical flux, commonly µmol/cm2h. For more information see Fick's Law of Diffusion.
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Iontophoresis
Mechanism
There are a number of factors that influence iontophoretic transport including skin pH, drug concentration and characteristics, ionic competition, molecular size, current, voltage, time applied and skin resistance. The current density of the treatment electrode is perhaps the most important variable relative to the degree of ion transfer. Studies suggest that comparable iontophoretic doses delivered at low currents over longer periods are more effective than those delivered by high currents over a short periods (Anderson et al, 2003).The isoelectric point of the skin is ~4; therefore, under physiological conditions, with the surface of the skin also buffered at or near 7.4, the membrane has a net negative charge and electroosmotic flow is from anode (-) to cathode (+). The phenomenon of electroosmosis has been used as a means to augment the anodic delivery of (in particular) large, positively charged drugs, the transport numbers of which are often extremely small (and whose iontophoretic enhancement therefore depends heavily upon electroosmosis) and to promote the transdermal migration of uncharged, yet polar, molecules, the passive permeation of which is typically very small.
The application of a charge to the skin alters the skin’s permeability increasing migration of the active ingredient into the epidermis. There are a number of pathways that the ingredients could take, but research suggests that the majority of drugs permeate the skin via appendageal pores, including hair follicles and sweat glands, although some delivery is via the paracellular channels and minimal quantities are transcellular.
Transport of lipophilic drug molecules is believed to be facilitated by its dissolution into the lipid matrix of the stratum corneum however hydrophilic drugs which are thought to permeate through the open pores or cutaneous appendages (hair follicle and sebaceous glands) only accounts for 0.1% of the total skin surface area.[1]
Uses
Reverse iontophoresis is the term used to describe the process whereby molecules are removed from within the body for detection. In reverse iontophoresis the negative charge of the skin at buffered pH causes it to be permselective to cations causing solvent flow towards the anode. This flow is the dominant force allowing movement of neutral molecules, including glucose, across the skin. This technology is currently being used in such devices as the GlucoWatch which allows for blood glucose detection across skin layers using reverse iontophoresis.Iontophoresis is commonly used by physical therapists for the application of anti-inflammatory medications. Common diagnoses treated with Iontophoresis include plantar fasciitis, bursitis and hyperhidrosis. Iontophoresis of Acetylcholine is used in research as a way to test the health of the endothelium by stimulating endothelium dependent generation of nitric oxide and subsequent microvascular vasodilation. Acetylcholine is positively charged and therefore placed in the anode.
See also
References
1. ^ Katrin Moser et al, Passive skin penetration enhancement and its quantification in vitro. 2001. J Pharm.
A cathode is an electrode through which (positive) electric current flows out of a polarized electrical device. Mnemonic: CCD (Cathode Current Departs). To dispel a common misconception, often incorrectly inferred from the correct fact that in all electrochemical
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An anode is an electrode through which (positive) electric current flows into a polarized electrical device. Mnemonic: ACE (Anode Current Enters).
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Electromigration is the transport of material caused by the gradual movement of the ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms.
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In electrochemistry, physics and vascular plant biology, electro-osmosis, also called electroendosmosis, is the motion of polar liquid through a membrane or other porous structure (generally, along charged surfaces of any shape and also through non-macroporous materials
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flux, both with rigorous mathematical frameworks.
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- In the study of transport phenomena (heat transfer, mass transfer and fluid dynamics), flux is defined as the amount that flows through a unit area per unit time, the volumetric flow rate.
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Fick's laws of diffusion describe diffusion and can be used to solve for the diffusion coefficient D. They were derived by Adolf Fick in the year 1855.
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First law
Fick's first law is used in steady-state diffusion, i.e...... Click the link for more information.
In electrochemistry, physics and vascular plant biology, electro-osmosis, also called electroendosmosis, is the motion of polar liquid through a membrane or other porous structure (generally, along charged surfaces of any shape and also through non-macroporous materials
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Epidermis is the outermost layer of the skin. It forms the waterproof, protective wrap over the body's surface and is made up of stratified squamous epithelium with an underlying basal lamina.
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Paracellular transport refers to the transfer of substances between cells of an epithelium.[1][2]
It is in contrast to "transcellular transport", where the substancees travel through
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It is in contrast to "transcellular transport", where the substancees travel through
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Paracellular transport refers to the transfer of substances between cells of an epithelium.[1][2]
It is in contrast to "transcellular transport", where the substancees travel through
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It is in contrast to "transcellular transport", where the substancees travel through
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Anti-inflammatory refers to the property of a substance or treatment that reduces inflammation. Anti-inflammatory drugs make up one half of analgesics, remedying pain by reducing inflammation as opposed to opioids which affect the brain.
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Plantar fasciitis
Classification & external resources
Areas of pain caused by inflammation of the plantar fascia which connects the area of the foot near the toes with the heel.
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Classification & external resources
Areas of pain caused by inflammation of the plantar fascia which connects the area of the foot near the toes with the heel.
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MeSH D002062 Bursitis is the inflammation of one or more bursae, or small sacs of synovial fluid, in the body. Bursae rest at the points where internal functionaries, like muscles and tendons, slide across bone.
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Hyperhidrosis
Classifications and external resources
ICD-10 R 61.
ICD-9 780.8
Primary hyperhidrosis is the condition characterized by abnormally increased perspiration, in excess of that required for regulation of body temperature.
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Classifications and external resources
ICD-10 R 61.
ICD-9 780.8
Primary hyperhidrosis is the condition characterized by abnormally increased perspiration, in excess of that required for regulation of body temperature.
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The chemical compound acetylcholine, often abbreviated as ACh, was the first neurotransmitter to be identified. It is a chemical transmitter in both the peripheral nervous system (PNS) and central nervous system (CNS) in many organisms including humans.
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endothelium is the thin layer of cells that line the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. Endothelial cells line the entire circulatory system, from the heart to the smallest capillary.
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Nitric oxide or Nitrogen monoxide is a chemical compound with chemical formula NO. This gas is an important signaling molecule in the body of mammals including humans and is an extremely important intermediate in the chemical industry.
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Iontocaine, known by the brand name Numby, is local anesthetic administered via iontophoresis through the skin. It can numb up to 10 mm of skin as quick as 10 minutes. It is a 2% lidocaine, 0.01 mg/ml epinephrine solution. It is currently only manufactured by IOMED, Inc.
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Electrophoresis is the most known electrokinetic phenomena. It was discovered by Reuss in 1809 [1]. He observed that clay particles dispersed in water migrate under influence of an applied electric field.
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Phonophoresis is the use of ultrasound to enhance the delivery of topically applied drugs. Phonophoresis has been used in an effort to enhance the absorption of topically applied analgesics and anti-inflammatory agents through the therapeutic application of ultrasound.
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