Abstract Importance of the field Transdermal delivery of macromolecules provides an attractive alternative route of drug administration when compared to oral delivery and hypodermic injection, because of its ability to bypass the harsh gastro-intestinal tract and deliver therapeutics non-invasively. However, the barrier properties of the skin only allow small, hydrophobic permeants to traverse the skin passively, greatly limiting the number of molecules that can be delivered via this route. The use of low-frequency ultrasound for the transdermal delivery of drugs, referred to as low-frequency sonophoresis LFS , has been shown to increase skin permeability to a wide range of therapeutic compounds, including both hydrophilic molecules and macromolecules. Recent research has demonstrated the feasibility of delivering proteins, hormones, vaccines, liposomes, and other nanoparticles through LFS-treated skin.
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PowerPoint Presentation: Advantages Virtually painless when properly applied. Provides option for patients unable to receive injections. Reduced risk of infection due to non-invasive nature. Medications delivered directly to the treatment site. Minimizes potential for tissue trauma from an injection. Treatments are completed in minutes. PowerPoint Presentation: An excessive current density usually results in pain.
Burns are caused by electrolyte changes within the tissues. The high current density and time of application would generate extreme pH, resulting in a chemical burn. This change in pH may cause the sweat duct plugging perhaps precipitate protein in the ducts. Electric shocks may cause by high current density at the skin surface.
Ionic form of drug in sufficient concentration is necessary for iontophoretic delivery. PowerPoint Presentation: A positive ion will be delivered from the positive electrode and a negative ion will be delivered by the negative electrode.
Here the choice of drug is very important whether it is ionized or unionize When a negatively charged drug is to be delivered it is placed under negatively charged active electrode from which it is repelled, attracted towards the positive electrode placed PowerPoint Presentation: Iontophoresis enhances transdermal drug delivery by three mechanisms Ion-electric field interaction provides an additional force that drives ions through the skin.
The flow of electric current increases the permeability of the skin. Electro-osmosis produces bulk motion of solvent that carries ions or neutral species with the solvent stream. Electro-osmotic flow occurs in a variety of membranes and is in the same direction as the flow of counter-ions.
Electrodes that contain and disperse the drug. Localized treatment site. PowerPoint Presentation: Selecting the Appropriate Ion Negative ions accumulating at the positive pole or anode Produce an acidic reaction through the formation of hydrochloric acid. Produce softening of the tissues by decreasing protein density-useful in treating scars or adhesions.
Some negative ions can also produce an analgesic effect salicylates. Positive ions that accumulate at the negative pole Produce an alkaline reaction with the formation of sodium hydroxide. Produce hardening of the tissues by increasing protein density. PowerPoint Presentation: Treatment Precautions Patient has a good understanding of the existing condition which is to be treated Uses the most appropriate ions to accomplish the treatment goal Uses appropriate treatment parameters and equipment set-up PowerPoint Presentation: Factors Affecting Iontophoretic Delivery of the Drug Operational Factors I.
Composition of formulation: Concentration of drug solution pH of donor solution Ionic strength Presence of co-ions II. Controlled and novel drugdelivery.
Sonophoresis:Biophysical basics of transdermal drug delivery. India:CBS publishers and Distributors;