Iontophoresis ppt

Iontophoresis-basics

1. IONTOPHORESIS PRESENTED BY: SANA ROOHI M. PHARMACY 1

2. Contents Introduction Principle of Iontophoresis Mechanism of Iontophoresis Factors affecting iontophoretic drug delivery Iontophoretic devices Applications Conclusion References 2

3. Introduction Iontophoresis (ionophoresis, electrophoresis or cataphoresis, is a technique used to enhance transdermal penetration of substances through the application of electric current . It is facilitated movement of ions across a membrane under the influence of an externally applied small electrical potential difference (0.5 mA/cm 2 or less) Transdermal drug delivery by Iontophoresis 3

4. It has proved to enhance the skin penetration and the release rate of a number of drugs having poor absorption/permeation profile through the skin. The skin , being a semi-permeable membrane, allows only a small amount of any drug molecule to passively penetrate the skin. Ionized drugs do not easily penetrate this, unless an external source of energy is provided to drive the drug across the skin. It enhances the delivery of ionized as well as unionized moieties. 4

5. SKIN The stratum corneum is an important component of the skin layers, responsible for preventing loss of body fluids, and for blocking the entry of exogenous substances. The three pathways that a medication uses to overcome the stratum corneum are: Intracellular (diffuse around corneocytes) Transcellular (diffuse directly through the corneocytes) Via appendices (hair follicles, sebaceous and sweat glands). 5

6. Anatomy of skin 6

7. ADVANTAGES OF IONTOPHORESIS It is a localized, non-invasive, convenient and rapid method of delivering water soluble, ionized medication into the skin. Reduces the chance of dose variation Self-administration is possible. It provides benefits of bypassing hepatic first pass effect , and higher patient compliance. Enables continuous or pulsatile delivery of drug. Permit easier termination of drug delivery. Improves the delivery of polar molecules as well as high molecular weight compounds. 7

8. DISAVANTAGES OF IONTOPHORESIS Difficulty in stabilizing the therapeutic agent in the application vehicle. Complexity of the drug release system. Prolonged skin exposure usually results in pain, sweat duct plugging, hyper hydrate the tissue surrounding the ducts Possibility of cardiac arrest Ionic form of drug in sufficient concentration is necessary. High molecular weight 8000-12000kDa results in uncertain rate of delivery. 8

9. PRINCIPLE Iontophoresis is based on the principle enunciated by Du Fay, in which charges with the same signal repel and charges with opposite signals attract , facilitating the penetration of ions through the skin. The drug is applied under an electrode of the same charge as the drug, and a return electrode is placed at a neutral site on the body surface. The current below the level of the patient’s pain threshold is allowed to flow. The electrical current significantly increases the penetration of the drug into surface tissues by repulsion of like charges and attraction of opposite charges. 9

10. MECHANISM The primary channel for transport is through sweat glands . Once the drug has passed through the outer layer of skin, it reaches to its site of action. Mechanism of iontophoretic transport involves diffusion, migration or electroosmosis. Electroosmosis is the bulk flow of fluid occurring in the same direction as the flow of counter ions when a voltage difference is applied across a porous membrane. On application of an electromotive force the drug is repelled and moves across the stratum corneum towards the cathode, which is placed elsewhere on the body. 10

11. At physiological pH, human skin has a slight negative charge and counter ions are usually cations. Therefore, flow occurs from anode to cathode electroosmotically thus, enhancing the flux of cationic drugs. REVERSE IONTOPHORESIS: The application of an electric current across the skin is used to extract a substance of interest from within or beneath the skin to the surface for testing. Can be used in diagnosing diabetes, cystic fibrosis . Mechanism of Iontophoresis 11

12. FACTORS AFFECTING IONTOPHORETIC DRUG DELIVERY Operational Factors: I. Composition of formulation: Concentration of drug solution pH of donor solution Ionic strength Presence of co-ions II. Physicochemical properties of the permeant: Molecular size & Molecular weight Charge Polarity III. Experimental conditions: Current density Duration of treatment Electrode material Polarity of electrodes Biological Factors: Regional blood flow Skin pH Condition of skin 12

13. Optimal Current Variables Current Type: DC Current Amplitude: 1.0 - 4.0 mA Treatment Duration: 10-20 minutes Total Current delivered: 40-80mA/min The basic formula for using iontophoresis is: I x T x ECE = grams of substance introduced I: Intensity (Amp), T: Time (hrs) ECE: (Electro-Chemical Equivalent) represents standardized figures for ionic transfer with known currents and time factors. 13

14. The most common electrodes used are - Al foil, Pt, Ag/AgCl . Active pad - This electrode have a small chamber covered by a semipermeable membrane into which ionized solution may be injected. Dispersive pad - Also known as inactive pad. IONTOPHORETIC DEVICE: Produce continuous direct current, assures unidirectional flow of ions. It Consists of a timer Intensity control(1 to 5 mA) Constant voltage Automatic shutdown 14

15. APPLICATIONS Transdermal delivery of insulin, thyrotropin-releasing hormone, leuprolide, gonadotropin-releasing hormone, arginine-vasopressin and some tripeptides. Diagnostic applications: Iontophoretic application of pilocarpine is primary test in the diagnosis of cystic fibrosis. Treatment of ischemic leg ulcers with the use of histamine iontophoresis. Treatment of dermatophytosis (copper sulfate) and sporotrichosis (potassium iodide). Iontophoretic application of idoxuridine is effective in aborting episodes of herpes simplex. 15

16. Cont… Treatment of hyperhidrosis: Tap water iontophoresis uses a mild electrical current (15–20 mA) that is passed through tap water to temporarily shut off sweat glands. Iontophoresis with hyaluronidase is used in the treatment of lymphedema of the limbs. Introduction of “artificial skin pigment” (iron oxide and titanium oxide) into the skin, iodine iontophoresis to reduce scar tissue, and administration of antibiotics (penicillin) in burn patients. Calcium chloride, magnesium sulfate for control of musculoskeletal spasms, Dexamethasone for inflammation. 16

17. Orion model Medtherm Phoresor model (hyperhidrosis) Lidosite (Lidocaine) E-Trans ( Fentanyl ) CONTRAINDICATIONS: Pregnant women's Patients with pacemakers or metal implants(joint replacements), cardiac conditions, or epilepsy Children Commercially developed Iontophoretic DDS 17

18. Iontophoresis is a means of applying pharmaceuticals based on physicochemical principles of attraction or repulsion of charges.  The iontophoretic delivery of macromolecules can be used in non-invasive transdermal delivery of peptide-based pharmaceuticals. Combination of iontophoresis with electroporation, chemical enhancers, sonophoresis, may provide easier and more accurate delivery of macromolecules and poorly water soluble compounds. CONCLUSION 18

19. REFERENCES Jain, N.K. (1997), Controlled and novel drug delivery, 1 st ed, New Delhi, CBS Publishers & Distributors, pp. 191-205. Krueger, E., Claudino Junior, J., Scheeren , E., Neves , E., Mulinari , E. and Nohama , P. (2014), Iontophoresis: principles and applications, 27(3), pp.469-481. Murugan , K. and kumar , P. (2017), International Journal of Pharmacy and Technology. Srinivas , C. and Rai , R. (2005), Iontophoresis in dermatology, Indian Journal of Dermatology, Venereology and Leprology , 71(4), p.236. 19

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