INTRODUCTION TO IONTOPHORESIS AND PHONOPHRESIS

1. IONTOPHORESIS
AND
PHONOPHORESIS
BY : KOMAL
MPT 1 SEM

2. INTRODUCTION
The term iontophoresis is simply defined as ion transfer (ionto = ion;
phoresis = transfer) which means introduction of ions into the body using
direct electrical current.
It is a specialized technique of electrical stimulation that uses electrical
polarity of continuous direct current to ionize medicines placed beneath
surface electrodes and transfers them into the body through the skin.

3. MECHANISM OF IONTOPHORESIS
There are two mechanisms that are usually involved in iontophoretic
transport.
• Electro-migration
• Electro-osmosis
• Electro-migration: It is also referred to as electro-repulsion. There occurs
movement of ions across a membrane (the skin) under the direct influence
of an electric field. There are two electrodes, cathode and anode. When an
electric field is passed, the negatively charged drugs repel into the skin
under the cathode whereas, the transfer of positively charged drugs
happen under the anode.
• Electro-osmosis: This is the second mechanism and electro-osmosis is
considered as the volume flow induced by the current flow. It depends on
the physiochemical properties of the molecules and the polarity of the
applied current. For example- When negative charges are placed on the
cathode (-), they will migrate trans dermally towards anode (+)

5. PHYSICS OF IONTOPHORESIS
• Current required for ion transfer that is the continuous galvanic current is
obtained from the standard low voltage generators as well as battery operated
units.
• Physical considerations that need to be done while following iontophoresis
are:
The Amount Of Substance Introduced :
Amount of substance introduced = I X T X ECE
Where I is intensity of current in amperes
T is the time in hours
ECE is equal to electrochemical equivalence of the substance

6. • Ionic Polarity: The basis of successful ion transfer lies in physics principle “like
poles repel and unlike poles attract’ . Ions with a polarity which is the same
as that of the stimulating electrode are repelled into the skin.
• Low Level Amperage : The lower the intensity of the current the greater is the
amount of penetration of ions through the skin.
• Enlarged Negative Electrode: The negative electrode is more irritating than
the positive electrode due to the formation of caustic sodium hydroxide.
High concentration of hydrogen ions and the relative rapidity of reactions at
the cathode suggests the need of reducing the current density under the
negative electrode to avoid undue irritation and possible burns .So for
reducing irritation, the negative electrode is made larger than the positive as
it lowers yhe current density.

7. PHYSIOLOGICAL EFFECTS OF IONTOPHORESIS
ION PENETRATION:
• penetration does not exceed 1 mm
• subsequent deeper absorption through the capillary circulation.
• The bulk of deposited ions at the active electrode are stored, to be depleted by the sweep of circulating blood.
ACID/ALKALINE REACTION:
• The anode produces an acid reaction ,a weak hydrochloric acid. The anode is sclerotic and tends harden tissue serving as an analgesic
due to release of local oxygen.
• The cathode produces a strong alkaline reaction, sodium hydroxide .The cathode is sclerolytic ,a softening agent releasing hydrogen
serving in the management of scars ,burns and keloids.
HYPEREMIA:
• Both the positive and negative electrodes produce hyperemia and heat due to the resulting vasodilatation.
• The cathodal hyperemia is generally more pronounced and takes more time to disappear than that of the anode.
• Generally, hyperemia under both electrodes does not lasts more than one hour.
DISSOCIATION:
• ionizable substances dissociate in solution releasing ions, with the passage of direct current into the solution migrate toward the
other pole.
• Gets absorbed through the capillary circulation.

8. PRINCIPLES OF APPLICATION OF IONTOPHORESIS
• The skin should be abrasion / cut free and the area carefully washed
(soap & water is fine).
• Dry electrodes are inappropriate and should not be used.
• If pregelled electrodes are being used, ensure that a good even contact is
achieved.
• Adequate fixation of the electrode and pad to the skin needs to be
carefully maintained.
• Uneven current distribution can easily lead to skin burns and/or irritation
• Explain to the patient what is expected and ensure that they know to
report immediately if any untoward or painful sensations are felt.
• Turn the current up slowly to the required amount At the end of the
treatment time, ensure that the current is turned down slowly.

10. INDICATIONS OF IONTOPHORESIS
• Local anesthesia : In the cases of trigeminal neuralgia and herpes zoster iontophoresis is widely used.(Mendes et al. 2021) It is widely used
in the patients who have a strong aversion to hypodermic needles for inducing local anesthesia. Agent used:lidocaine or procaine.
• Relief of idiopathic hyperhidrosis: Glycopyrronium bromide is used for the effective and safe treatment for the hands and feet. It also
suppresses the sweating as exocrine sweat glands in palms and soles are innervated by sympathetic system but stimulated by acetylcholine
so in this case the introduction of anticholinergic agent (glycopyrronium bromide ) supresses sweating.
• Application of antibiotics : commonly used to apply antibiotics to avascular areas. In the cases of chronic infected wounds metallic silver
iontophoresis is commonly used. In case of chronic non healing ulcers the treatment with xanthinol nicotinate which is the capillary dilator
and histamine is used
• Application of anti inflammatory drugs: useful in the treatment of tendonitis and bursitis. According to (demirtas and omer 1998 )showed
successful treatment of epicondylitis with iontophoresis of sodium salicylate and sodium diclofenac was reported. (Pratzel at al. 1986)
demonstrated that the concentration of nsaid in the tissues is more with iontophoresis compared to their percutaneous absorption.
• Neurogenic pain: iontophoresis of vinca alkaloids is found to be of great benefit in the cases of post herpetic neuralgia trigeminal neuralgia
and pain due to carcinoma.

11. • Edema relief: the Hyaluronidase is found to be effective in the reduction of
local edema.(Panzade et al. 2012)
• Ischemic ulcers :In the cases of Ischaemic and chronic non healing ulcers
the iontophoresis of zinc is found to be very useful.
• Scar mobilization : iontophoresis of iodine and chlorine is used to enhance
the extensibility of the scar tissue in association with passive stretching
(Cummings 1987)
• Fungal infection : in fungal infections like tinea pedis iontophoresis of
copper is found to be useful(Fathima et al.2020)
• Allergic rhinitis : the iontophoresis of zinc (khan et al. 2011)and copper is
found to be useful in the cases of allergic rhinitis thereby providing relief

12. CONTRAINDICATIONS OF IONTOPHORESIS
RELATIVE CONTRAINDICATION
1. Epilepsy, Seizures
2. Heart diseases
3. Recent wounds
4. Gastritis
ABSOLUTE CONTRAINDICATIONS
1. Metal implants
2. Pacemakers
3. pregnancy
4. Skin grafting
DANGERS OF IONTOPHORESIS
1. Burn
2. Electric shock
3. Skin irritation
4. Systemic effects:with use of anticholinergic drugs there can be headache,abdominal pain and mild dryness

13. Background: A 56-year-old man developed pain in the region inferior to the right patella subsequent to a fall onto the
knee while playing tennis. There was immediate mild, localized swelling, which resolved with ice and rest. The acute pain
subsided after about 7 days, but the patient then noted significant stiffness following rest, localized tenderness, and pain
with climbing stairs, squatting, and kneeling. The physical examination was benign except for mild swelling and point
tenderness of the infrapatellar tendon, as well as crepitus to palpation of the tendon during active knee extension.
Impression: Infrapatellar tendinitis.
Treatment Plan: In addition to rest and local ice application, a course of iontophoresis of dexamethasone was initiated.
The area was prepared appropriately, and the cathode (negative polarity) was used as the delivery electrode. A total of 60
mA/min of current was delivered on an every-other-day schedule for a total of six treatments.
Response: There was a slight increase in the symptoms following the initial treatment, which persisted for approximately
12 hours following the second treatment. The signs and symptoms then began to diminish, and the patient was symptom-
free following the fifth treatment. A progressive increase in physical activity was initiated, and the patient returned to
preinjury function 4 weeks later.
CASE STUDY

14. Discussion :
• What tissues were injured and affected?
• What symptoms were present?
• What phase of the injury-healing continuum did the patient present for care in?
• What are the therapeutic agent modality’s biophysical effects (direct, indirect, depth, tissue affinity)?
• What are the therapeutic agent modality’s indications and contraindications?
• What are the parameters of the therapeutic agent modality’s application, dosage, duration, frequency in this case
study?
• What other therapeutic agent modalities could be used to treat this injury or condition? Why? How?

15. PHONOPHORESIS
• Phonophoresis is defined as the migration of drug molecules into the
skin and subcutaneous tissues under the influence of the ultrasound
• The effects produced in the tissues are caused both by ultrasound
and the nature of drug that is applied.
• It is not only dependent on the frequency intensity duty cycle and
treatment duration of ultrasound but also on the nature of the drug
molecule itself.
• Lower the frequency of current greater the penetration of the drug

17. PRINCIPLE
• Phonophoresis relies on perturbation of the tissue causing more rapid
particles movement and thus encouraging absorbtion of the drug.
• Ultrasound facilitates the passage of some drugs into and through the skin
• The effects aredue to the both absorption of the drug and to the ultrasound
• Lower ultrasonic frequencies appear to lead to deeper drug penetration
• The quantity of drug entering the skin is proportional , in general , to the time
and intensity of ultrasound application

18. MECHANISM OF ACTION
• Ultrasound may cause intracellular diffusion from high speed vibration of drug molecules
along with vibration of cell membrane.
• Cavitation effect cause mechanical stress,temperature elevation or enhanced chemical
reactivity causes drug transport.
• It delivers the drug whole molecules into tissues . It is depend on the nature of drug
molecule (analgesics , anti- inflammatory ) intensity , duty cycle and treatment duration.

19. EFFECTS OF PHONOPHRESIS
• The thermal effect of ultrasonic increases tissue permeability .
• The medication follows the path of beam .
• Continuous ultrasonic at an intensity great enough to produce thermal effects may induce
a pro-inflammatory response .
• If the goal is to decrease inflammation , pulsed ultrasonic with low spatial-averaged
temporal peak intensity may be the best choice

20. DRUG USED IN PHONOPHORESIS
• HYDROCORTISONE OR OINTMENT (1-10%)
• LIDOCAINE(4-5%)GEL (XYLOCAINE)
• ZINC OXIDE CREAM (20%)
• METHYL SALICYLATE (4.8%)OINTMENT OR SALICYLATE
10% OINTMENT (MYOFLEX)
• IODINE (4.7%)OINTMENT (IODEX)

21. APPLICATION
• Select the particular transducer (1 MHz or 3 MHz) and test the machine like that
described under ultrasound therapy.
• Select a suitable coupling gel and apply it over the area to be treated.
• Mix the drug (in the form of a gel) into the coupling gel using a spatula.
• Put the transducer head over the site ,switch on the machine, select the mode
(preferably pulsed )intensity ,(between 1 - 1.5 W/cm2 )and start moving the
treatment head in the usual manner.
• Determine the timing of treatment, which is based on the area of application.
Generally 1 minute for every 10 cm2 is the duration selected
• After the end of treatment remove the remaining gel and drug from the patient skin
and transducer surface.

22. INDICATIONS
• Post – injury condition ( dislocation , distortion of joint, inflammation of muscle, tendon )
• Pain in rheumatic diseases
• low back pain of neurological origin ( root pain discopathies , sciatica )
• bursitis and similar inflammatory ailments
• Carpal tunnel syndrome
• Foot / toe pain / Achilles sprain and strain
• Wrist / hand / elbow / shoulder sprains and Strains
• Hip / thigh sprain and strain
• ligament strain
• Osteoarthritis
• post – exercise recovery

23. CONTRAINDICATIONS
• Vascular problems
• Radiotherapy
• Implants
• Anaesthetic area
• Allergy to the drugs
• Altered sensation
• Pregnancy
• Malignancies

25. ULTRASOUND DOSE CALCULATIONS

26. MACHINE SETTINGS
• MACHINE FREQUENCY:
• 3MHz -absorbed more rapidly in the tissues, and therefore is considered to be most appropriate for
superficial lesions
• 1MHz- energy is absorbed less rapidly with progression through the tissues, and can therefore be more
effective at greater (Deeper)depth.
• PULSE RATIO: determines the proportion of time that the machine is ON compared with the OFF time.

27. Ideally try for 1:4 or 1:3 for the ACUTE lesions, 1:2 and 1:1 for the SUBACUTE lesions
and 1:1 or Continuous for the CHRONIC lesions.

28. • TREATMENT INTENSITY: the intensity of ultrasound required at the target tissue will vary with the
tissue state.
• For acute lesion, the less intensity is required to achieve/maintain the tissue excitement.
• For chronic lesion ,greater intensity is required at the lesion in order to instigate a physiological response.

29. The rate at which ultrasound is absorbed in the tissues can be approximately determined by the half value depth - this is the tissue depth at
which 50% of the ultrasound delivered at the surface has been absorbed.
The average 1/2 value depth of 3MHz ultrasound is taken at 2.5cm and that of 1MHz ultrasound as 4.0 cm.
It is suggested that the intensity required at depth is established first, then the most appropriate frequency selected and these two factors are
used to determine the surface intensity required.

31. • SIZE OF THE LESION
• Greater the size of the lesion, the longer the duration of the ultrasound that will be required in order to
achieve a particular effect.
• there is a direct relationship between treatment area and treatment time.
COMPILING THE TREATMENT DOSE
Based on the principle that:
• One needs to deliver 1 minute worth of ultrasound energy (at an appropriate frequency and intensity) for
every treatment head that needs to be covered.
• The size of the treatment area will influence the treatment time, as will the pulse ratio being used.
• The larger the treatment area, the longer the treatment will take.
• The more pulsed the energy output from the machine, the longer it will take to deliver 1 minutes worth of
ultrasound energy

32. Example 1
Ultrasound treatment for a (very) acute lesion of the lateral ligament of the ankle
•The lesion is superficial, hence a 3MHz frequency would be most appropriate
•The lesion is acute, thus an intensity of 0.2 W/cm2 should be sufficient to treat the lesion
•There is no need to increase the surface dose to allow for loss of ultrasound at depth (<0.5cm depth to reach the tissue)
•The lesion is acute, therefore a pulse ratio of 1:4 will be most appropriate
•Using the large treatment head, it is estimated that the target tissue is approximately the same size as the treatment head
(i.e. the head fits on to the tissue once)
Working on the principle of 1 minutes worth of ultrasound per treatment head area, the total time taken to treat the lesion
will be (1 minute) x (number of times the treatment head fits over the lesion) x (the pulse ratio) which in this instance = (1) x
(1) x (5) = 5 minutes.
[the factor to account of the pulsing can be easily worked out by adding together the two components of the pulse ratio thus,
pulsing 1:4, adds up to 5, so multiply by 5. Pulse at 1:2, adds up to 3, so multiply by 3 etc]
The final treatment dose will therefore be 3MHz ; 0.2 W/cm2 ; Pulsed 1:4 ; 5 minutes

33. Example 2
Ultrasound treatment of a subacute lesion of the lateral ligament complex of the elbow and superior radioulnar joint
• The lesion is superficial, hence a 3MHz frequency would be most appropriate
• The lesion is sub-acute, thus an intensity of 0.4 W/cm2 should be sufficient to treat the lesion
• There is no need to increase the surface dose to allow for loss of ultrasound at depth
• The lesion is sub-acute, therefore a pulse ratio of 1:2 will be most appropriate
• Using the small treatment head (due to the nature of the surface), it is estimated that the target tissue is approximately twice
the size of the treatment head (i.e. the head fits on to the tissue twice)
Working on the principle of 1 minutes worth of ultrasound per treatment head area, the total time taken to treat the lesion will be
(1 minute) x (number of times the treatment head fits over the lesion) x (the pulse ratio) which in this instance = (1) x (2) x (3) = 6
minutes.
The final treatment dose will therefore be 3MHz ; 0.4 W/cm2 ; Pulsed 1:2 ; 6 minutes

34. Example 3
Ultrasound treatment of a chronic lesion of the anterior capsule of the shoulder (glenohumeral joint
•The lesion is not superficial, hence a 1MHz frequency would be most appropriate
•The lesion is chronic, thus an intensity of 0.5 W/cm2 should be sufficient to treat the lesion
•There IS a need to increase the surface dose to allow for loss of ultrasound at depth, and using the tables above, it is estimated
that the required surface dose will need to be 0.88 W/cm2 (this is assuming that the capsule is about 3cm below the skin surface.
This will depend on the size of the patient – it is not a universal formula)
•The lesion is chronic, therefore a pulse ratio of 1:1 will be most appropriate
•Using the large treatment head, it is estimated that the target tissue is approximately twice the size of the treatment head (i.e.
the head fits on to the tissue twice)
Working on the principle of 1 minutes worth of ultrasound per treatment head area, the total time taken to treat the lesion will
be (1 minute) x (number of times the treatment head fits over the lesion) x (the pulse ratio) which in this instance = (1) x (2) x (2)
= 4 minutes.
The final treatment dose will therefore be 1MHz ; 0.88 W/cm2 ; Pulsed 1:1 ; 4 minutes

35. REFERENCES
• Electrotherapy simplified by B.K. Nanda.
• Therapeutic modalities by for physical therapists by William Prentice.
• https://www.electrotherapy.org/ultrasound-dose-calculations.

36. THANK YOU