This document provides an overview of iontophoresis drug delivery systems. It begins with definitions and the historical development of iontophoresis. Some key advantages include enhanced drug penetration, control of transdermal rates, and avoiding infection. Disadvantages include the need for drugs to be in aqueous solution and ionized. The document discusses the electrical properties of skin, pathways of ion transport, and mechanisms of iontophoresis. Factors affecting the process and common equipment are also outlined. The document concludes with applications and examples of drugs studied for iontophoretic delivery.

1. A
SEMINAR ON
IONTOPHORESIS
DRUG DELIVERY SYSTEM
1
By:Rajesh L. Dumpala
(B.Pharm, M. Pharm.) PhD. ( Pursuing)
Research Scientist,
Alembic Research Centre. Vadodara
E.Mail:-rdumpala64@gmail.com

2. CONTENT
 Introduction
 Advantages and disadvantages
 Electrical property of skin
 Route and mechanism of system
 Factor affecting iontophoresis
 Equipments and devices
 Evaluation
 Application
2

3. INTRODUCTION
Definition:-
Iontophoresis can be defined as the
permeation of ionized drug molecules
across biological membranes under
the influence of electrical current.
3

4. HISTORICAL DEVELOPMENT:-
 The idea of applying electric current to increase the
penetration of electrically charged drugs into surface
tissues was probably originated by varatti in 1747.
 Ledus demonstrated the introduction of strychnine and
cyanide ions in to the rabbits at the beginning of the 20th
century , placing two rabbits in series with a direct
current generator.
 Today, the treatment of hyperhidrosis is the most
successful and popular application of iontophoresis in
dermatologic medication.
4

5. ADVANTAGES
 Enhanced drug penetration (of selected drugs) over
passive transport .
 Allows strict control of transdermal penetration rates.
 Permits rapid termination of drug delivery through
termination of current or ultrasound.
 Skin remains intact, therefore low risk of introducing
infection .
 Not immunologically sensitizing.
 In many cases, greater patient satisfaction.
 Home units available for iontophoresis.
5

6. ADVANTAGES OVER OTHER DELIVERY SYSTEM
 Iontophoresis enlarges the range of drug
candidates for transdermal administration.
 Fast skin recovery than parentral route.
 Less risk of systemic absorption than injection.
 Less anxiety provoking or painful than injection
 Increases therapeutic efficacy by bypassing
hepatic “first pass” metabolism.
 Inter and intra subject variability is considerably
reduced in contras to oral route.
6

7. DISADVANTAGES
 Can be time-consuming to administer
 Drugs must be in aqueous solution and must be in
ionized.
 Minor tingling, irritation, and burning can occur.
(these effects can often be minimized or
eradicated with proper technique or current
adjustment ).
 The skin itself imposes a barrier to the delivery of
some medication.
 Additional ions act as charged carriers or active
competitors for the drug applied.
7

8. ELECTRICAL PROPERTY OF THE SKIN
 Stratum corneum is composed of layers of horny
cells which are a good insulator and forms the
principal barrier of the body to electrical
conductivity.
 In addition to electrical resistance, skin tissue also
have a capacitance because of their ability to store
electrons, and are thus electrically capacitors so
skin layer is said to be reactive. A reactive circuit is
said to be present impedance rather than
resistance.
 The human skin reportedly shows a high
impedance to alternating current of low frequency,
but the impedance was found to decrease from 130
to 30 kilo ohm as the A.C input was increased from
1 to 1000 Hz. 8

9. HUMAN SKIN
9

10. ROUTE AND MECHANISM OF SYSTEM
 The greatest concentration of ionized
species is expected to move into some
regions of the skin where either the skin is
damaged ,or along the sweat glands and
hair follicles, as the diffusional resistance on
the skin to permeation is lowest in these
regions.
10

11. PATHWAY OF ION TRANSPORT
Percutaneous absorption may take place simultaneously
by any combination of the three main pathways that
include; the intercellular (paracellular) pathway between
the conneocytes along the lamellar lipids, the intracellular
(transcellular) pathway through the cells or the
appendageal (shunt) pathway via hair follicles, sweat ducts
and secretary glands.
11

12. Fig. 1. A diagrammatical representation of human skin:
(a) appendageal pathway; (b) intercellular pathway.
12
T.S. of SKIN

13. Mechanism:-
 In iontophoretic treatment electric potential may alter
the molecular arrangement of the skin components
hence change in skin permeability.
 The “flip-flop gating mechanism” could be responsible
for pore formation in the stratum corneum which is rich in
keratin, an alpha-helical polypeptide.
13

14.  Pores are thus opened up as a result of repulsion between
neighboring dipoles, and water molecule and ions will flow
in the pore channels to neutralize the dipole moments. The
phenomenon should lead to an enhancement in skin
permeability for peptide and protein molecules, and other
charged molecules.
 The isoelectric point of the skin is between 3 and 4,means
pores have positive charge below pH 3 and negative
charge below pH 4 ,so it is easy to introduce basic drug.
14

15. v
Anode + Cathode -
Analyte –
Cl -
Neutral
analyte Analyte +
Na +
Drug +
Na +
Drug –
Cl -
Neutral
drug
BLOOD VESSEL
The number of electrons flowing through the external circuit is a direct reflection of the
amount of ionic charges flowing through the skin.
The transport number and the intensity of current are the two main parameters
controlling the iontophoretic flux.
ELECTROCHEMISTRY OF IONTOPHORETIC CIRCUIT
[ ELECTROREPULSION ]
15

16. FACTOR AFFECTING IONTOPHORESIS
 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 and Molecular weight
Charge
Polarity
III. Experimental conditions:
Current density
Current profile
Duration of treatment
Electrode material
Polarity of electrodes
16

17. Biological Factors:-
 Intra and inter subject variability
 Regional blood flow
 Skin pH
 Condition of skin
17

18. EQUIPMENTS AND DEVICES
Iontophoresis
Generators
 Produce continuous
direct current
 Assures unidirectional
flow of ions
18

19. IONTOPHORESIS
GENERATOR
 Intensity control
 1 to 5 mA
 Constant voltage
output that adjusts to
normal variations in
tissue impedance thus
reducing the
likelihood of burns
 Automatic shutdown
if skin impedance
reduces to preset limit
19

20. IONTOPHORESIS
GENERATOR
 Adjustable Timer
 Up to 25 min
20

21. IONTOPHORESIS
GENERATOR
 Lead wires
 Active electrode
 Inactive electrode
21

22. CURRENT INTENSITY
 Increase intensity slowly until patient reports tingling or
prickly sensation.
 If pain or a burning sensation occur intensity is too great and
should be decreased.
 When terminating treatment intensity should be slowly
decreased to zero before electrodes are disconnected.
22

23. CURRENT INTENSITY
 Maximum current intensity should be determined by size
of the active electrode.
 Current amplitude usually set so that current density falls
between 0.1-0.5 mA/cm2 of the active electrode surface.
23

24. TREATMENT DURATION
 Treatment duration ranges between 10-20 minutes with 15
minutes being an average.
 Patient should be comfortable with no reported or visible
signs of pain or burning.
 Check skin every 3-5 minutes looking for signs of skin
irritation.
 Decrease intensity during treatment to accommodate
decrease in skin impedance to avoid pain or burning.
24

25. COMMERCIAL ELECTRODES
 Sold with most iontophoresis systems.
 Electrodes have a small chamber covered by a
semipermiable membrane into which ionized solution
may be injected .
 The electrode self adheres to the skin.
25

26. ELECTRODE PREPARATION
 To ensure maximum contact
of electrodes skin should be
shaved and cleaned prior to
attachment of the electrodes.
 Do not excessively abrade
skin during cleaning since
damaged skin has lowered
resistance to current and a
burn might occur more
easily.
26

27. ELECTRODE PREPARATION
 Attach self-adhering active
electrode to skin
27

28. ELECTRODE PREPARATION
 Attach self-adhering active
electrode to skin
 Inject ionized solution into
the chamber
28

29. ELECTRODE PREPARATION
 Attach self-adhering active
electrode to skin
 Inject ionized solution into
the chamber
 Attach self-adhering
inactive electrode to the
skin and attach lead wires
from generator to each
29

30. EVALUATION
 In-vitro evaluation:-
In this experiment , the glassware is assembled,
sandwiching the excised skin. The drug formulation is
placed in donor reservoir and normal saline is placed
in the receptor resevoir. The electrode are connected.
Periodically , solution is withdrawn from the receptor
reservoir and assayed for the drug.
 In-vivo evaluation:-
The system is evaluated in rats for transdermal
iontophoretic delivery of vasopressin and analogue in
rats.
30

31. APPLICATION
 Treatment of hyperhydrosis, diagnosis of cystic
fibrosis, other therapeutic uses.
 Delivery of metallic and non-metallic ions.
 Delivery of vasodilators.
 Delivery of local anesthetics.
 Delivery of steroids.
 Uses of iontophoresis in neurosciences.
31

32. List of Drugs Investigated Recently for Iontophoretic Delivery
32

33. 33

34. REFERENCES
 Singh P, Maibach H(1996), Iontophoresis: an alternative
to use of carriers in cuteneous drug delivery, Advanced
drug delivery reviews; 18, 379-394.
 Rawat S, Vangurlekar S, Rakesh B, Jain S, Shrikarti G,
Transdermal delivery by iontophoresis, Indian journal of
pharmaceutical science; Year 2008, Vol .70, Issue:1, 5-
10.
 Swarbrick James, “Encyclopedia of Pharmaceutical
Technology”; informa healthcare USA Inc, 2007, 3rd ed.;
vol. 4 p. .2119-2132.
 Controlled and novel drug delivery by N.K.Jain; CBS
publishers and distributors; 191-206. 34

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