IONTOPHORESIS

IONTOPHORESIS

Presented byRasika.Walunj

Modern College Of Pharmacy (For Ladies),

Moshi, Pune. 412105.

Definition

Introduction of Ions Into The Body Using Direct

Electrical Current

Transports Ions Across A Membrane Or Into a Tissue

Facilitated movement of ions across a skin

(membrane) under the influence of an externally

applied small electrical potential difference

Route Of Intophoresis

Mechanism

The basic principle of Iontophoretic drug delivery is that

“like charges” repel “like charges” so the drug ions are

repelled or pushed into the underlying tissue.

When direct (DC) current is applied to an ionized drug

solution, the ions that have the same charge as the

electrode are repelled by the electrode and are delivered

through the skin.

Sweat ducts are primary paths by which ions move

through the skin

…..Continue

A negatively charged drug delivery electrode transports (repels or

pushes) the negative drug ions into the underlying tissue

A positively charged drug delivery electrode transports positive

drug ions into the skin.

…..Continue

Transport of drugs across the skin involves either diffusion,

migration or electro osmosis.

Electro osmosis 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 charged, porous membrane.

This flow involves motion of fluid without concentration

gradient and is a significant factor affecting iontophoresis

Factors Affecting Iontophoretic Delivery of the Drug

Operational Factors : Biological Factors

I. Composition of formulation:

Concentration of drug solution pH of donor solution: determines the ionization of

peptides

Ionic strength: increase in ionic strength will decrease

drug delivery, as extraneous ions compete with the drug

ions.

…..CONTINUE

Presence of co-ions: generally more mobile and smaller in size than

the drug ions itself and can dominate the penetration

into the skin thereby causing a decrease in transdermal flux

of the drug e.g. buffer

II. Physicochemical properties of the permeant:

Molecular size and weight: smaller ions are transported at a faster

rate than larger ions

Polarity: the compounds which are hydrophilic are considered ideal

candidates for optimum flux

..Continue Charge: the sign of the charge determines the mechanism by which

iontophoresis will proceed e.g., electro-repulsion or electro-

repulsion and electro-osmosis .

The transport of cations has been shown to be better than anions for

amino acids and peptides ,an increase in charge will require pH to

be decreased, which in turn shall directly decrease the

electroosmosis and electrotransport process. An increased positive

charge on peptide, cause it to bind tightly to the membrane creating

a reservoir which in turn can decrease the rate at which the steady

state flux will be achieved

…Continue Experimental conditions:

I. Current density

II. Current profile

III. Duration of treatment

IV. Electrode material

V. Polarity of electrodes

Biological Factors

I. Intra and inter subject variability

II. Regional blood flow

III. Skin pH

IV. Condition of skin

MERITS Of IDDS1. Indicated to introduce ions into the body using direct current

follows faradays law of currant.

2. Advantages are it’s painless,

3. Sterile /noninvasive

4. For administration of charged drug

5. Better compliance

6. Small quantity of drug

7. Sports therapist /physiotherapist choice

DEMERITS Of IDDS1. Skin irritation2. Some time problem of failure of battery 3. Electrode may fails due to corrosion4. Selection of appropriate ion form drug 5. Not easy to use/Special direction and skilled person6. Some problem of antigenisity/allergy.7. Sensitivity to chemical environment 8. Itching 9. Skin pigmentation10. Skin resistance is always less than11. The initial value when current of 0.16ma Is applied for 10 sec.

Clinical applications

1. Analgesia2. Scar modification3. Wound healing4. Edema5. Burns6. Inflammatory MS conditions7. CA++ deposits8. Hyperhidrosis9. M spasm10. Fungi open skin lesions11. Herpes12. Gout

THANK YOU….