topical therapy

1. PRINCIPLES OF TOPICAL THERAPY
Dr MIKHIN G THOMAS

2. • Topical therapy is the use of medicaments directly on surface
of skin or mucosa
• Stratum corneum the rate limiting barrier to percutaneous drug
delivery.
• Drug penetration is inversely proportional to the thickness of
the stratum corneum .
• Maximal over mucous membranes>eye lids>scrotum.

3. • Surface area : 1.6-2 m sq.
• Enhancement of systemic treatment measures
• An extensive region for the application and
absorption of topical medications
• Penetration via transepidermal or
transfollicular pathways

4. PERCUTANEOUS ABSORPTION
• TRANSCELLULAR PENETRATION
(across the cells)
• INTERCELLULAR PENETRATION
(between the cells)
• TRANSAPPENDAGEAL PENETRATION
(via hair follicles, sweat and sebaceous
glands, and pilosebaceous apparatus)

5. • Selection of an appropriate agent
• Thoughtful consideration of the areas of
the body affected

6. 1. State of the diseased skin(pathologic changes)
2. Age of the patient
3. Area of the body
4. Concentration of the drug
5. Type of vehicle
6. Method of application
7. A defined duration of use that maximizes efficacy and
minimizes adverse side effects.
BASIC

7. • Drug concentration
• Thickness
• Surface area applied
• Friction and heat
• Occlusion
- Cover skin surface easily, mix readily with sebum
- Promotes hydration of skin
• Hair follicles
• Cutaneous circulation
FACTORS AFFECTING
PERCUTANEOUS ABSORPTION

8. • Vinyl gloves or plastic wrap, occlusion
with cotton gloves or socks .
•Greatest benefit – increased hydration
and temperature, prevents wash off.
•Increases efficacy as well as side effects .
OCCLUSION

9. • Specify concentration of the drug, the vehicle and the frequency
of application.
• Quantity to be used.
• Precisely where it should be/should not be applied.
• Timing of application in relation to bathing or other treatments.
• Warn regarding potent irritant or allergic effects, factors that
influence systemic absorption.
PRESCRIBING TOPICAL
TREATMENT

10. • w/w : % representing proportion of the formulation,
by weight, which is the active constituent. ( 1% = 1
g of drug in 100g formulation)
• w/v : % representing proportion of the volume of
the formulation.( 1% = 1 g in 100ml)
• ‘parts’ : describe conc. of solution (1 part in 1000
solution contains 1 g in 1L = 0.1 % w/v)
DRUG CONCENTRATION

11. Frequency of application
• Maximize response whilst avoid side effects.
• Excessive application – systemic exposure
• Emollients- Frequent application several times a day
• Active preparations – once or twice a day.
• Pharmacological actions persist long after drug has
left the skin surface.
• Increasing interval between applications effective
way of tapering intensity of treatment.
• Rebound and tachyphylaxis

12. QUANTITY TO BE APPLIED

13. • Fingertip unit:
- Qty of ointment, extruded from a tube with nozzle 5 mm
diameter, extending from distal crease of forefinger to
ventral aspect of fingertip.
- O.49 g in males, 0.43 g in females; covers area appx 300 cm
sq.
• Rule of hand:
- Area of the size that can be covered by four adult
hands can be treated by 1g of ointment or two FTUs.

14. • Estimates of the quantity of cream or ointment
have varied.
• Recent study : male patients treating themselves,
applied an average of 20 g of ointment, and
females applied 17 g.
• Quantity required for 1 week of once-daily
application to the whole body would be
approximately 140 g for males and 120 g for
females.
QUANTITY OF APPLICATION

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

16. Cleansing measures
1. Soap and water wash
2. 3% solution hydrogen peroxide or saline
wash
3. Wet dressings
4. Soaking with grease or oils
5. After using the above said cleansing
measures , mechanical removal of crusts
and scales

17. Vehicle
• Substances that bring specific drugs
into contact with the skin
• Non specific effect- cooling,
protective, emollient, occlusive,
astringent, carrier.

19. Powders
Greasy
pastes
Cooling
pastes
Shake
lotions
Drying
pastes
Greases
w/o
creams
o/w
creams

20. Powders
• Mixture of finely divided drugs and/or
chemicals in dry form.
 Cooling effect
 Prevents friction
 Absorbs moisture
 Covering property.
• Most useful in intertriginous areas.
• Not used in oozing dermatoses due to crust
formation.

21. • Organic powders – starch
more absorbent
Prone to microbial decomposition
• Inorganic powders
- Zn oxide
- TiO2
- Stick- Lanolin
- Slip- starch, zinc stearate

22. • Zinc oxide, Talcum- clean, white, absorbent
• Kaolin, Diatomaceous earth- highly absorbent
• Titanium oxide- light and puffy
• Boric acid- disinfectant properties
• Tannic acid- astringent
• Nystatin- anti candidal
• Neomycin- antibacterial
• Aluminium acetate- antiperspirants

23. • Finely mulled and of small particle size
• Insoluble powder should not be dusted into open
wounds
• Previous application should be washed off
CHECKPOINT

24. Liquids
• Solutions = Liquid preparations that
contain one or more soluble chemical
substances usually dissolved in water
and that do not, by reasons of their
ingredient, method of preparation or
use, fall into another group of
products.
• Solvent for the active drug
• Cooling effect, soothing and
antipruritic.

25. • Water : important in Dermato therapeutics,
used in creams, shake lotions, cooling pastes
and wet dressings.
• Alcohol (spirit) : 94.9 to 96 % C2H5OH by
volume, absolute alcohol = 99% C2H5OH
- Most useful solvent in pharmacy next to
water.
• Glycerol : Trihydroxy alcohol obtained by
hydrolysis of fats; clear syrupy liquid used in
shake lotions
• Propylene glycol : viscous liquid miscible with
water and alcohol.
• Ether : Readily evaporating liquid used in
tinctures, collodions.

26. Baths
• Mode of treatment where whole or a part of
the body is immersed.
• Widespread less exudative lesions.
- General cleansing baths
- Medicated baths
- Cleansing of particular body areas.
• Amount of water:
- Full length bath tub: 150 – 250 L (adults)
- For hand and foot: 5 – 10 L
• Duration: Should be limited to 30 min.

27. • Cleansing baths:
- Removes accumulated dirt, debris, crusts,
scales and adherent remains of
medication.
- Temp. – 95-100 deg. F
- Washing with soft cloth and copious
lather of plain white soap with < 0.0125 %
of free alkali.
- Careful and repeated rinsing, warm spray
followed by cool one.
- Drying immediately.

28. • Medicated baths
- Removes dirt, debris, crusts
& scales, and have soothing,
antipruritic, decongestive &
anti inflammatory actions.
- Effects of active medical ingredients – antiparasitic,
antieczematous, antiseborrhoiec.
- KMnO4 baths - exudative, vesicular & bullous eruptions,
superficial infected dermatoses.

29. •Solutions for wet dressings
Sterile water
Tap water
Any doubt- boil the water first

30. • Solutions of choice:
1. Normal saline (0.9%) – 1 tsp salt per pint
(500ml) water
2. Astringents
- Burrow’s solution: 5% aluminium
acetate diluted 1:20-1:40 in water.
- Condy’s compresses: Freshly prepared
1:8000 solution of KMnO4.
3. Antimicrobial agents: Silver nitrate 0.1%-
0.5%, acetic acid 1%

31. • Open wet dressings:
- Clean laundered unstarched cloth
preferred, dipped in prepared solution,
wrung and applied over the area; removed
every 5-10 min and reapplied.
- 10 - 30 min.
- 3-4 times a day.
• Wring out to be soppy and not drippy
• Avoid maceration of surrounding skin
- Indicated in acute, swollen, inflamed,
vesiculating or oozing dermatoses.
- Not more than 1/3rd body surface.

32. • Closed wet dressings
- Protected from evaporation.
- More maceration, less cooling.
- Treatment of cellulitis, abscess.

33. COMPRESSES
A/c exudative conditions
 Dil KMNO4 compress
 Fresh milk
 Liquor alumni subacetatis(1:15-
30)
 Liquor alumini acetatis
(Burrow’s soln)
 AgNO3 soln 0.1-0.5%
 Thiersch soln
 EUSOL

34. - Psoralen bath- 3.75 mg/L
- Starch bath – soothing action in generalized itching
dermatoses.
- Tar bath – Psoriasis(good ventilation)
• Bran, cornstarch, Oatmeal- soothing action
• Chamomile tea in sitz bath- pruritus and eczema
• Tannic acid bath- astringent

35. WET DRESSINGS
Useful form of topical therapy that consists of application
of aqueous liquid preparation to the skin.
Methods- Compresses and soaks

36. Mechanical cleansing action.
Antipruritic action
 Soothening agents- relieves superficial inflammation
 Opens blisters, brings medications to the eroded or
ulcerating areas
Decongestant action by causing vasoconstriction.
Keratolytic action by macerating the skin.
Facilitates drainage.
Act as vehicles for drugs.
Prevents rapid change of temperature.

37. SOAKS
• Preferred for extremities
• Convenient for the patient

38. Paints
• Aqueous, alcoholic or hydro alcoholic
preparations applied to skin or mucous
membrane.
Tinctures
• Solutions of active ingredients in alcohol, ether,
chloroform or other organic solvents.
Advantages:
- Treatment confined to circumscribed areas.
- Water insoluble medicament as substitute for
ointments.
- Ease of application and relative lack of
messiness.

39. Paints
• Antibacterial
• Anticandidal
• Dermatophytosis
Gentian violet
• Antibacterial(folliculitis)Brilliant green
• Intertrigo
• Paronychia
• Tinea infections
Castellani paint

40. POULTICES

42. Powders
Greasy
pastes
Cooling
pastes
Shake
lotions
Drying
pastes
Greases
w/o
creams
o/w
creams

43. GREASES
• True fats : Triglycerides, and waxes which are aliphatic or cyclic
alcohols with one or two OH groups esterified with fatty acids
• Mineral greases : Saturated hydrocarbons of the paraffin series,
petroleum distillation products.
• Advantages:
- Diluents and solvents
- EMOLLIENTS ; coats SC preventing evaporation of water, exerting
softening and moisturizing effects.
- Greater absorption of drug due to occlusive effect
- Not prefered in oozy dermatoses and hairy areas.

44. TRUE FATS
• Vegetable oils : composed of triglycerides
which contain large proportion of
unsaturated fatty acids.
- Vulnerable to oxidation- rancidity
manifesting as unpleasant odour
- Eg: Olive oil, coconut oil, cocoa butter,
shea butter, Castor oil, Arachis oil
• Waxes
- Beeswax- chemically stable, free cerotic
acid and myricyl palmitate; thickening
agent for creams, ointments.
- Emulsifying wax – cetostearyl alcohol,
sodium lauryl sulphate and water

45. PARAFFINS (MINERAL GREASES)
• Aromatic and unsaturated
compounds eliminated; fully
saturated and thus more stable
and not vulnerable to oxidation.
• Examples:
- Liquid paraffin: White mineral oil,
is a colourless, transparent oil of
rather high viscosity.
- Petrolatum (Vaseline) : Yellow soft
paraffin & White soft paraffin.

46. Ointments
• Semisolid preparations intended for external
application.
• Ointment Bases
 One of the most important ingredients used in the
formulation of topical preparations
 carrier of the medicaments.
 control the extent of absorption of medicaments
incorporated with them.

47. Ointments
Advantages:
- Best occlusive
- Good hydration
- Used in chronic, dry, brittle,
lichenified dermatoses.
- Most potent effect of the drug.
- Fewer preservatives as they
contain less water and do not
sustain microorganisms.

48. Ointments
• Disadvantages:
- Difficult to spread and wash.
- Adherent to skin
- Decreased evaporation/heat loss.
- Cannot be used in acute weeping lesions
and intertriginous areas.
- Cosmetically unacceptable

49. Powders
Greasy
pastes
Cooling
pastes
Shake
lotions
Drying
pastes
Greases
w/o
creams
o/w
creams

50. Lotions & Shake lotions
• Lotions are liquid formulations which are usually simple
suspensions or solutions of medications in water, alcohol or
other liquids.
• Shake lotions are composed of aproportion of powders (40%)
and liquids, when correctly compounded a highly viscous
liquid results. Shaken well before use.
Uses
- Subacute or chronic less inflammed
dermatoses.(transitional stages)
- Generalized dermatoses
- Drying action
• Avoid:
- Exudative lesions

51. • Advantages:
- Convenience of application and removal
- Less chances of systemic and toxic effects
- Variations possible by altering the nature and ratios of inert and active
ingredients.
• Disadvantages
- Too drying or irritating.
- Difficulty in removing the sometimes very adherent remains of lotions,
scales and secretions.
- Stinging sensation.
- Sedimentation of solids in the preparation.

52. Pastes
• Semisolid preparations consisting of greases
which carry in suspension insoluble, finely
dispersed powders
• Equal parts of suspended powder and greasy
or oily vehicle.
• Uses:
- Acute inflammation (prefer wet
dressings, lotions)
- sub acute inflammation.(prefer lotions)
- Dry scaly, thickened skin conditions.(prefer
ointments)
• Zinc oxide
• Talcum
• petrolatum

53. • Advantages:
Comparison with ointment:
1. Thicker, drier and more solid.
2. Less impermeable, less penetrating, less macerating, less
heating.
3. Stiffness permits accurate localization.
• Disadvantages:
- Greasy pastes messy and water insoluble; difficult to
remove and apply.
Eg: Lassars paste – Zinc oxide 24% + Starch 24% + Salicylic
acid 2% + petrolatum

54. Drying pastes & Varnishes
Drying pastes:
• By carefully choosing the proportion between the powders
and liquids; increasing the percentage of powders; possible
to obtain paste like substance drying on the skin.
• Soothe and dry the skin; used along with dressings as paste
bandages.
Varnishes:
• Applications which dry on the skin as a smooth, resistant,
covering layer readily soluble in water.
• Prepared by dissolving powder, or a powder mixture which
absorbs water and swells, in water and glycerol

55. Powders
Greasy
pastes
Cooling
pastes
Shake
lotions
Drying
pastes
Greases
w/o
creams
o/w
creams

56. Creams
• Semisolid emulsions containing both lipid
and water.
• Emulsions are suspensions, either lipid
droplets in water (oil in water = o/w) or
aqueous solutions suspended in an oily
medium (water in oil = w/o).
• Transition between lotions and ointments.

57. EMULSIFYING AGENTS
• Emulsions contain droplets of one substance,
called inner or disperse phase, suspended in
liquid or semisolid outer or continuous phase.
• Emulsifying agents act as interphase
stabilizing emulsions.
• Emulsifying wax, cetearyl alcohol

58. W/O
Immiscible with
water, difficult to
wash off
Emollient, lubricant and
mildly occlusive. {COLD
CREAMS}
O/W
Water miscible
Cooling and
soothing, well
absorbed into skin.
{VANISHING
CREAM}

59. Liniments
• Alcoholic or oleaginous emulsions intended for
external application with rubbing.
• Alcoholic or hydroalcoholic vehicle- rubefacient,
counterirritant, penetrant.
• Oleaginous vehicle (oils)- massage
• Shaken well before use to ensure uniform
distribution of dispersed phase.

60. Fixed dressings
• Bandages impregnated
• Hardens and stiffens
• Flexible cast
• Unnas boot
• Excludes effects of external
irritants, trauma, scratching
• Varicose complexes of legs

61. Plasters
• Adhere to the skin
• Macerating action
• Plantar warts, callus
• 1-7 days
• Salicylic acid, phenol

62. • Readily spreading
• During or after bath
• Asteatotic eczema, ichthyosis, atopic
dermatitis
• Coconut oil, glycerin, liquid paraffin
paraffin
BATH OILS

63. GELS
• Might be regarded as thickened lotions.
• Semisolid preparations containing high molecular
weight polymers, such as methylcellulose.
• Tendency to dry when left on the skin
• Uses:
- Treatment of scalp and other hairy areas.
- Cosmetically acceptable formulation for use on the
face.

64. COLLODIONS
• Liquid preparations consisting of cellulose nitrate in
organic solvent.
• Evaporate readily to leave flexible film which can
hold medicaments in contact with skin.
• Uses:
- Seal minor cuts and abrasions.
- Apply salicylic acid to warts.

65. MICROSPONGES
- Patented polymeric delivery systems.
- Controlled release of topical agents using
microspheres, macroporous beads. (10-25
mm in diameter)
- Extremely small, inert, indestructible
spheres, gets collected in the crevices of
the skin and slowly release medications,
time bound or in response to stimuli.(eg:
rubbing, temp, pH)
- Significantly reduce irritation of effective
drugs.

66. LIPOSOMES
- Lipid bilayer surrounding an aqueous phase.
- Both hydrophilic and hydrophobic molecules
(dissolved in membrane) delivered.
- Drug delivery by fusion of lipid bilayer with cell
membrane bilayer, by diffusion or by endocytosis.
- Mainly used in cosmetics and reduce irritation from
topicals.

67. AEROSOLS
- Facilitates delivery of drugs formulated as solutions,
suspensions, powders and semisolids.
- Drug kept in an emulsion with a foaming agent
(surfactant), solvent (water or ethanol), and a
propellant.
- Foam broken by heat and rubbing, dispensing thin
layer of drug.
- Non irritant.
- Expensive; non eco-friendly (CFCs)

68. HUMECTANTS
• Glycerine
• Gelatin
• Propylene glycol
• Sorbitol
• Urea

69. PENETRATION ENHANCERS
• Dimethyl sulfoxide
• Propylene glycol
• Salicylic acid
• Urea

70. PRESERVATIVES
• Ointments and w/o emulsions don’t require
preservatives.
• Lotions, o/w creams and gels, as they contain water,
easily contaminated by bacteria.
• Animal and vegetable oils susceptible to oxidation.
• The ideal preservative is effective at a low
concentration against a broad spectrum of organisms,
nonsensitizing, odor free, color free, stable, and
inexpensive

71. Commonly used preservative
include:
Methyl hydroxy benzoate
Propyl hydroxy benzoate
Chlorocresol
Benzoic acid
Phenyl mercuric nitrate

72. CHOICE OF PREPARATIONS
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

73. UNSUITABLE COMBINATION OF
DRUG AND VEHICLE
• Pharmaceutical incompatibility which inactivates the drug.
 Zinc oxide in pastes inactivate dithranol and salicylic acid
• Ointment bases may be innapropriate for the skin condition
that is being treated
• Vehicle may bind too firmly to the drug to permit adequate
delivery into the diseased layer of skin

74. CHOICE OF THE TYPE OF APPLICATION
• Irritable dermatoses- treatment to be started with bland
application such as wet dressing or cooling pastes
• Powders- for cosmetic and hygienic purposes
• Liquids – for open wet dressing in acute oozing
dermatoses.
• Occlusive wet dressings enhance drug penetration and
advantageous in hyperkeratotic and fissured conditions.
• Ointments- emollient effect, occlusive effect(disadvantage
in oozing conditions)

75. • Environmental factors: Heat,
humidity, wind, exposure to
sunlight.
• Site of involvement and
accessibility.
• Time of application
• Habits, occupation of the patient.

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

77. Hazards due to topical
treatment
• M.C. - localized irritant or allergic reactions.
 Minimized by optimizing the concentration and treatment
intervals and by selection of the correct vehicle.
• Contact allergy: active medicament & constituents of the
vehicle-Ethylenediamine, propylene glycol, emulsifiers, sorbic
acid , cetyl and stearyl alcohols and fragrances.
• Malignancies- nitrogen mustard

78. • Rare
• Absorption depends on the region of skin being treated.
• Occlusion enhances absorption.
• Greater in children due to their relatively high ratio of skin
surface to body mass.
• Increased penetration in the elderly ; hydrophilic drugs
• Inflammation impairs barrier function and increases
absorption.
SYSTEMIC SIDE EFFECTS

79. LASSAR’S PASTE
• ZNO 24
• STARCH 24
• SALICYLIC ACID 2
• VASELINE 50

80. DITHRANOL PASTE
• ZNO 24.5
• STARCH 24.5
• DITHRANOL 1
• VASELINE 50

81. WHITFIELD OINTMENT
FORMULATION ORIGINAL MODIFIED
BENZOIC ACID 5 6
SALICYLIC ACID 3 3
VASELINE 25
COCONUT OIL 100 100

82. CALAMINE LOTION
• CALAMINE(ferric oxide 15g
• ZNO 5g
• BENTONITE 3g
• NA CITRATE 0.5g
• LIQUID PHENOL 0.5mL
• GLYCERINE 5mL
• ROSE WATER 100mL

83. ZINC PASTE
• ZNO 25
• STARCH 25
• VASELINE 50 UNNA’S PASTE
ZNO 25
GELATIN 35
GLYCERINE 20
AQUA 20
ZN-COAL TAR PASTE
ZNO 6
COAL TAR 6
EMULSF WAX 5
STARCH 38
PARAFFIN 45

84. TO CONCLUDE....
• Mainstay of treatment in dermatology
• Sound knowledge regarding concentration,
vehicle, drug, frequency of application
• Proper advice to be given to the patient
• Side effects and hazards of the drugs to be
kept in mind

85. THANK