topical therapy in dermatology

1. PRESENTER: DR.
KEZHALETO
MODERATOR: DR ALOK

2. • DEFINITION:
A topical medication is one that is applied to body surfaces
such as skin or mucous membranes.
• ADVANTAGES:
Achieve high concentration of drug in skin.
Minimal exposure to other organs.

3. • Stratum corneum is the rate limiting barrier to percutaneous drug
delivery.
• Drug penetration is inversely proportional to the thickness of stratum
corneum .
• Regional Differences in Penetration (decreasing order)
1. Mucous membrane
2. Scrotum
3. Eyelids
4. Face
5. Chest and back
6. Upper arms and legs
7. Lower arms and legs
8. Dorsa of hands and feet

5.  The vehicle or the formulation
 Concentration of drug
 Frequency of application
 Quantity to be used
 Site of application
 Precise timing of application

6. OCCLUSION
• Vinyl gloves or plastic wrap, cotton gloves or socks .
• Benefit – increased hydration and temperature, prevents wash off.
• Increases efficacy as well as side effects.
• To derive the greatest benefit from occlusion, the patient should
hydrate the skin by immersion in water for approximately 5
minutes before the application
• With many drugs, occlusion increases drug delivery by 10–100
times the amount of drug delivered when not occluded.

7. • Most used conventions are:
1. w/w : Percentage of drug as a proportion of weight of
formulation. (1% = 1 g of drug in 100g formulation)
2. w/v : Percentage of drug as a proportion of volume of
formulation. (1% = 1 g in 100ml formulation)
3. Parts : describe conc. of a drug in solution (1 part in 1000
solution contains 1 g in 1000ml = 0.1 % w/v)

8.  Must be specified to maximize the response and avoiding side
effects.
 Excessive can result in irritation, systemic exposure to drug and
unwanted side effects.
 Active preparations are usually given once or twice a day
 Emollients can be given frequent application several times a day

9. Can be determined by Finger Tip Unit and Rule of hand.
FINGER TIP UNIT (FTU)
1 FTU is equal to the quantity of ointment extruded from a tube
with a nozzle of 5mm diameter extending from distal crease of the
forefinger to ventral aspect of finger tip.
This unit weighs approximately 0.49 gm in males and 0.43 gm in
females and covers on average an area of approx 300 cm2.

10.  FTU is to be measured on adult finger before
being applied on children.
1 FTU
RULE OF HAND
Rule of hand states that an area of the size that can be covered
by four adult hands (including the digits) can be treated by 1gm of
ointment or two FTUs.

11. No. of units required for a single treatment of each anatomical
region in adults and children of various age:
AGE FACE &
NECK
1 UL 1 LL TRUNK
FRONT
TRUNK
BACK
WHOLE
BODY
3-6
MONTHS
1 1 1.5 1 1.5 8.5
1-2
YEARS
1.5 1.5 2 2.5 2.5 13.5
3-5 YEARS 1.5 2 3 3 3.5 18
6-10 YEARS 2 2.5 4.5 3.5 5 24.5
ADULT 2.5 4.5 7.6 6 7.5 40

12. SITE Relative levels of
absorption%
Sole 0.1
Palm 0.8
Forearm 1.0
Back 1.7
Scalp 3.5
Axila 3.6
Forehead 6.0
Scrotum 42

13. Vehicle include all the constituents of formulation apart from active
ingredients.
Ideal vehicle / base : non toxic, non allergic, non irritant, stable,
chemically inert, cosmetically acceptable , should not inactivate the
drug .
Vehicles have non specific beneficial therapeutic effects like
occlusion, hydration, cooling, soothing, astringent action.
They form the reservoir of active agent .
Vehicles include ointment , cream , gel , lotion, paste, powder , etc.

14.  Choice of vehicle depends on –
• Anatomical site to be treated
(scalp, face)
• Skin condition to be treated
(dry, exudative)

16.  Mixture of finely divided drugs and/or chemicals in dry form.
• Cooling effect
• Prevents friction
• Absorbs moisture
• Covering property
Generally used in intertriginous areas and on feet.
Adverse effects - caking, crusting, irritation, inhalation by the user.

17.  Powders are of two types:
Organic
Inorganic
Organic powders include starch, zinc/magnesium stearate.
 Inorganic powders include ZnO, titanium oxide, calamine, talc etc
• Insoluble powder should not be dusted into open wounds
• Previous application should be washed off

18. STARCH : more absorbent than inorganic powder . Used as dusting
powder & for surgical gloves. They should not be used in intertriginous
areas especially when infection is present
ZINC / MAGNESIUM STEARATE : smooth , fatty to touch .
They are not water wettable.
ZINC OXIDE : component of dusting powder, paste, shake lotions like
calamine lotion. it has cooling, covering, protective, astringent & U.V
reflecting properties, thus used in sunscreen.
TITANIUM OXIDE : chemically inert, better than ZnO in U.V reflecting
properties.
TALC : is hydrated magnesium polysilicate, has low specific gravity,
used for surgical gloves.

20. • Also referred to as cataplasm.
• It is a wet solid mass of particles, sometimes heated, that is
applied to diseased skin.
• Historically, poultices contained meal, herbs, plants and seeds.
• Modern poultices consists of porous beads of dextronomer.
• Used as wound cleansers and absorbtive agents in exudative
lesions like leg ulcers.

22.  They are semisolid, petrolatum based vehicles capable of
providing occlusion, hydration and lubrication.
Advantages:
- Provides best occlusion
- Good hydration
- Used in chronic, dry, brittle, lichenified dermatoses.
- Most potent effect of the drug.
- Fewer preservatives are required as they contain less water and
do not sustain microorganisms.

23. Disadvantages:
- Difficult to spread and wash.
- Adherent to skin
- Decreased evaporation/heat loss.
- Cannot be used in acute weeping lesions and intertriginous areas.
Ointment bases can be classified into 5 categories:
• Hydrocarbon bases
• Absorption bases
• Emulsion of water in oil
• Emulsion of oil in water
• Water soluble bases

24. • We commonly refer the hydrocarbon bases and absorption bases as
ointments and the water-in-oil/oil-in-water emulsion bases as creams
HYDROCARBON BASES
• Also called oleaginous bases. Often referred to as emollients
because they prevent evaporation of moisture.
• Petrolatum is the most common hydrocarbon base.
• Are greasy and can stain clothing.
• Stable and do not contain preservatives.
• Cannot absorb aqueous soln and thus are not used for water soluble
drugs.

25. ABSORPTION BASES
• Contain hydrophilic substance like lanolin, cholesterol.
• Can absorb aqueous soln thus suitable for water soluble drugs.
• Greasy to apply but easier to remove than hydrocarbon bases.
• Eg. Anhydrous lanolin and hydrophilic petrolatum
WATER SOLUBLE BASES
• Contain mainly polyethylene glycol.
• Are water soluble, don’t decompose, don’t support growth of mold,
therefore require no preservatives.
• Less occlusive, non staining, greaseless and easily washable.
• Eg. Topical antifungal , topical antibiotics like mupirocin .

26. Emulsions are two phase systems involving one or more immiscible
liquid dispersed in another, with the assistance of one or more
emulsifying agents.
Emulsifier is soluble in both phases and surrounds the dispersed
drops to prevent coalescence.
Preservatives added to increase shelf life.
Two types:
1. Oil in water emulsion
2. Water in oil emulsion

27. Oil in water emulsion
• Contain >31% water. Aqueous
phase may compose upto 80%.
• Less greasy, easy to apply and
remove
• After application, the aqueous
phase evaporates leaving behind
both a small hydrating layer of oil
and concentrate deposit of drug.
• Additionally contain a humectant
like glycerine and Polyethylene
glycol.
Water in oil emulsion
• Contain <25% water.
• More greasy and occlusive than o/w
emulsion.
• They provide a protective film of oil
that remains on the skin as an
emollient, while slow evaporation of
water provides cooling effects.

29. Semisolid vehicle, translucent in appearance and liquefy on contact
with skin and dry as thin greaseless film.
A gel consists of organic macromolecules uniformly distributed in a
lattice throughout the liquid.
After application, the aqueous or alcoholic component evaporates
and drug is deposited in concentrated form.
Suitable for facial or hairy areas - little residue left behind.
Non greasy, water washable, transparent, easy to apply.
However require preservatives.
Get removed by perspiration

30. They are semi-solid preparation containing a high proportion of
powders (up to 50%) into an ointment such as a hydrocarbon base
or a water-in-oil emulsion
The powders commonly used are zinc oxide, starch, calcium
carbonate, and talc
Helps to localize the effect of a drug
that may be staining or irritating, and
also functions as impermeable barriers.
They are less greasy than ointments,
more drying, and less occlusive

31. Subdivided into:
• Solutions
• Suspensions
• Emulsions
• Foams

32. SOLUTION
A solution involves dissolution of two or more substances into
homogenous clarity.
Solution may be:
Aqueous (eg: aluminium acetate/ burrow soln)
Hydralcoholic
Non-aqueous (alcohol, oils, PEG)
TINCTURE:
• It is a hydroalcoholic soln with concentration of
alcohol of approx 50%
• Eg: tincture of benzoin, tincture of iodine.

33. COLLODIONS:
• Non aqueous soln of cellulose nitrate
with ether and ethanol.
• Applied with brush.
• Mech- on evaporation it leaves behind thin flexible
film that hold the medication in contact with skin.
• Most commonly used to apply salicylic acid and lactic acid to
warts.
• Easy to apply, water repellent but inflammable.

34. LINIMENTS:
• Non aqueous solution of drugs in oil and alcoholic
soln of soap.
• Applied by rubbing or massaging.
• Used as counter irritant, analgesic, astrigent, emollient.

36. A suspension or lotion is a two phase system consisting of finely
divided insoluble drug dispersed in liquid (water, alcohol or other
liquid) in conc. upto 20%.
Suspended particles may coalesce and separate out - so shaking
of lotion is required prior to application.
Have drying, cooling and protective properties.
Adv- easy to apply, allow uniform coating, prefered in children.
Disadv- requires shaking, requires preservatives, more drying
than ointment.

37. SHAKE LOTION :
• Lotion in which powder is added to increase surface area of
evaporation.
• Consists of ZnO, talc, glycerol etc to which specific drug and
stabilizers are added.
• Tends to sediment - so need to shake the lotion to obtain
homogenous suspension.
• Eg: calamine lotion.

38.  They are triphasic liquids composed of oil, organic solvents and
water which are kept under pressure in aluminium cans.
 In pressurized dosage form, containing
active ingredient that upon valve
activation emits fine dispersion of
solid/liquid material in gaseous medium.

39.  Formulated with hydrocarbon propellent either butane or propane.
 The foam lattice is formed when valve is activated. Once in
contact with skin, the lattice breaks down, alcohol evaporates
within 30 sec and leaves minimal residue in skin.
• The alcohol component of the foam is thought to act as a
penetration enhancer, increasing drug delivery through the
intercellular route.
 Adv- easy to apply, spread easily, leaves minimal residues and
better compliance.

40. • Involves formulating the drug in a solution within a pure propellant.
• Propellant is a blend of non-polar hydrocarbons.
• On application it forms lattice transiently until it is broken by both
the heat of the skin or rubbing.
• Commonly used to deliver corticosteroids such as betamethasone
valerate & clobetasol propionate

41. ADVANTAGES -
• Do not require mechanical contact
• Easy to apply
• Remaining portion cannot be contaminated
DISADVANTAGES -
• Expensive
• Potentially ecologically damaging

42. • Paints are liquid preparation either aqueous, hydroalcoholic or
alcoholic.
• Applied with brush to skin or mucous membrane and then
evaporate.
• Most commonly used-
Wart paints containing
S.A & L.A

43. • This formulation contain porous beads, of size 10–25 um in
diameter .
• Extremely small, inert, indestructible spheres,
gets collected in the crevices of the skin and
slowly release medications, either time bound or
in response to stimuli. (eg: rubbing, temp, pH)
• Provide sustained release while decreasing the side effect.

44. Structures comprising an aqueous phase surrounded by a lipid
capsule.
Size vary from several nanometers to several microns.
Drug delivery is done by fusion of lipid bilayer with cell membrane
bilayer, by diffusion or by endocytosis
Mainly used in cosmetics and reduce
irritation from other topical agents

45. Emollients
Humectants
Thickening agents
Solvents
Emulsifying agents
Penetration enhancer
Stabilizer

46. • They are oily substances which form occlusive film over skin
surface, prevents evaporation, thus restore skin hydration .
• They soothen & soften the skin
• Examples : acetyl alcohol , stearyl alcohol, stearic acid, isopropyl
palmitate, squalene, lanolin, glycerin, petrolatum .

47. • They are hygroscopic agents, with high affinity for water & draws
the water into stratum corneum.
• Eg: Propylene glycol ,Sorbitol, Glycerine

48. • They increase viscosity of products or suspended particles in a
formulation.
• Eg: bee wax , xanthum gum , petrolatum.

49. • They increase the solubility of drug in the vehicle .
• Eg: Water, alcohol, ether , acetone

50. • It is a compound that is able to promote drug transport through the
skin barrier.
• CHEMICAL ENHANCER:
Increase penetration of drug through skin by increasing
hydration of stratum corneum or through keratolytic effect.
Eg: propylene glycol, urea, DMSO (dimethyl sulfoxide)

51. • PHYSICAL ENHANCER:
Increase penetration of drug through skin by altering the
architecture of stratum corneum
Eg: Application of a small electric current (ionophoresis),
ultasound energy (phono or sonophoresis),
Microdermobrasion, use of microneedles.

52. • Non therapeutic ingredients and include the preservatives,
antioxidants and chelating agents.
• PRESERVATIVES:
Protect the formulation from microbial growth.
An Ideal preservative is effective at a low temperature against
a broad spectrum of organisms, non sensitizing, odor free,
color free, stable and inexpensive.
Most commonly used - parabens
Others- halogenated phenol, sodium benzoate, propylene
glycol , thiomersol.

53. • ANTIOXIDANTS:
Prevent the drug or vehicle from degrading via oxidation.
Eg: butylated hydroxyanisole, butylated hydroxytoluene.
• CHELATING AGENTS:
Used to complex heavy metals.
Eg: sodium EDTA, citric acid.

54. Devices in the form of adhesive patches of various shapes and
sizes (5-20 cm2) which deliver the contained drug at a constant
rate into systemic circulation via stratum corneum.
Parts- backing film, drug reservoir, micropore membrane and
adhesive layer.

55. Drug is held in a reservoir between an occlusive backing film and
a rate controlling micropore membrane.
The undersurface of micropore membrane is smeared with an
adhesive, impregnated with priming dose of the drug.
The adhesive layer is protected by another film that is to be
peeled off just before application.
Drug is delivered at the skin surface by diffusion.
Designed to last for 1-7 days.

56. How to use transdermal patch
Use on clean, dry, non hairy area of skin
Avoid touching the adhesive surface
While applying it should be firmly pressed against skin for about
10 sec to ensure uniform contact or adhesion
Use patch for the designated period of time

57. Advantage-
Controlled release
Steady blood level profile
Better compliance
Adverse effects are local irritation and allergic contact dermatitis
to either an adhesive or the drug itself.

58. Mode of treatment where whole or a part of the body is immersed.
Used for widespread less exudative lesions.
Two types-
1. General cleansing baths - Removes accumulated dirt, debris,
crusts, scales and adherent remains of medication.
2. Medicated baths - Added effects of active medical ingredients
Eg. KMnO4 baths - exudative, vesicular & bullous eruptions,
superficial infected dermatoses.

59. Also known as wet dressing .
Used in the treatment of wet, exudative skin disease.
• Anti inflammatory action
• Anti bacterial action
• Wound debridement
• Drying of skin
INDICATION - Acute eczematous inflammation, Stasis ulcer,
Bullous impetigo, Herpes simplex, Infective exudative lesion of any
type

60. • Select dressing material.
• Fold it in about 6-8 layers
• Moisten it
• Apply on diseased part 10-15 min then remove , remoisten, reapply
every 10-15 min for ½ - 2 hr thrice a day.
• Not more than 1/3 of body surface area should be treated with wet
compresses at a time because it can lead to hypothermia .
• Commonly used solution - Normal saline 0.9%, Aluminium acetate
(burrows solution) 5%, Potassium permanganate, acetic acid 1%,
Silver nitrate 0.1%- 0.5%

61. OPEN COMPRESS
• Allow evaporation , thus
causes cooling & drying
• Uses absorbent dressing
• Require frequent change of
dressing
• Used in acute oozing
dermatosis, erosion , bullous
disorder
• It can cause hypothermia
CLOSE COMPRESS
• prevent evaporation & retain
heat & causes maceration
• Uses impermeable dressing
• Does not require frequent
change
• Used in abscess, cellulitis
• It can causes increase chance
of infection

62. • Depends on product ; disease ; patient; condition of the skin
Condition of skin Preparation of choice
Acute inflamed, red, swollen,
vesiculating or oozing dermatoses
Wet dressings, Lotions
Subacute, chronic, less inflamed Lotions, pastes, creams
Dry, scaly, thickened, lichenified Ointments, pastes
Generalized widespread eruptions Lotions, creams, baths

63. AVOID
• Hairy scalp- Shake lotion, non water washable ointment or paste
• Ext. ear canal- shake lotion, paste
• Face- strong keratolytics, anthralin, alcohol, menthol, phenol
• Axilla - macerating greases
• Pubic area - shake lotion
• Intertriginous areas - ointment or paste

64. • Most common - Allergic and Irritant Contact Dermatitis
• Others include Phototoxic, Photoallergic reactions, and induction
of Acne
• Irritant reactions can be minimized by applying treatment at the
optimal concentration and treatment intervals and by selection of
the correct vehicle
• Sensitization is more difficult to anticipate and to prevent, as
almost any component may sensitize
• Malignancies - Rare

65. Rare
• End-organ toxicity (cns, cardiac, renal, etc)
• Teratogenicity
• Drug interactions
• Type 1 hypersensitivity reactions
• Hypothalamic-pituitary-adrenal axis suppression
• Malignancies

66. THANK YOU

67. • Fitzpatric dermatology in general medicine
• Rooks text book of dermatology
• K.D tripathi , pharmacology
• Arndt, manual of dermatological therapeutics
• A practical guide to topical therapy in children. BJD 1998; 138 :
293-96