I A A Widhiartini, Dra, Apt., MSi

Pharmaceutical MedicineDepartmentSchool of MedicineUdayana University

Efficacy of topically therapy Penetration of skins

The body site or areas of the body applied State of the diseased skin Method of application

So many types of Vehicle available Many concentration

Potential Systemic Effect

Consider many factors influencing the therapeutic efficacy of topical treatment

Choose appropiately vehicle for topical preparation related to the dermatology disorders

Prescribe topical preparation appropriately

Outline

PRINCIPLES OF TOPICAL APPLICATION

First Concept of Topical Skin Therapeutics:

The first rule: "apply wet on wet and dry on dry.“ wet skin use wet dressings to dry up

the skin. when the skin is dry use ointments or

emollients.

The second rule: "apply cream to wet skin and ointment to dry skin."

The cream base of a topical preparation will absorb the wetness while the ointment base on dry skin will function as a barrier and will stop water loss and itch.

Second Concept of Topical Skin Therapeutics:

Pharmacological effect will only occur

when drugs can get in through stratum corneum

Lipid soluble drugs could get in through st corneum better than water soluble drugs

The fate of topically applied compound in skin:

FACTORS INFLUENCING THERAPEUTIC EFFICACY FOR

TOPICAL APPLICATION

Variation in penetration at different anatomic site

Hydration of the Stratum corneum Type of vehicle Frequency of application Quantities of drugs applied Inflammation Age Others

Factors influencing therapeutic efficacy for topical application:

Skin has certain permeability and its absorption through passive diffusion

Lipid soluble molecules and slight soluble in water will be absorbed better than water soluble molecules.

Stratum Corneum

Skin tickness and its location:■ mucosal■ scrotal■ eye lids■ face■ chest and back■ upper arm■ lower extrimities ■ palms■ nails

:Ointment (hydrocarbon, oily) forms an

occlusive layer ■ increase penetration.■ minimize hydration/ temperature↑,■ minimize loose of drugs due to washing

Frequency of Application■ Most corticosteroids should only be applied

once daily ■ Some emollient esp some protective cream

its absorption will be increased after frequent application (it is not because longer contact)

Quantity of drug applied■ quantity of drug applied should be sufficient enough to minimize excessive usage■ the quantity of drugs used should be depend upon the surface area affected

Others massages Reducing the size of drug particles

Dry skin in elderly will reduce absorption

CHOOSING APPROPRIATE VEHICLES

Function: drug’ vehicle will help drugs penetrates to the skin

Other function: cooling effect, protection, emollient effect, occlusive and astringent effect

Characteristics; stable chemically and physically; should not influence drugs efficacy, non-allergenic, non-irritative, cosmetically acceptable and easy to be applied

To increase water soluble or hydrophilic drugs’ absorption, hydrophilic base vehicle could be selected such as: lanolin, proplylene glycol to increase their penetration

vehicle will influence skin properties and its permeability so that drugs could be liberated well

vehicle could solute the drugs without reducing drug’s affinity to the skin

In order to maximize pharmacological effect particular vehicle should be selected to increase drug solubility and its liberation

Drugs:1.Water soluble --- bad penetration2.Lipid soluble --- good penetration

Vehicles:Ensure drugs penetrate through st corneumLipid soluble drug --- no problem on penetrationWater soluble drug --- increase penetration with vehicles

TOPICAL PREPARATION

Emollients help the skin’s surface retain the water content, e.g. Eucerin and Moisturising cream Maintaining comfort, improve performance, control

itching, reduce the overall need for active medication Enhancers

Remove heavy scale that otherwise impedes topical treatment

Salicylic acid and urea

a. Powder Advantage

powder could absorb skin moisture, give cooling effect, and minimize skin friction (intertriginosa area, and foot)

Disadvantage when applied on wet wound will be

irritating and form caking

a. Hidrocarbon ointment baseThe basis: Petrolatum, Vaselin album, vaselin flavum . Emollient effect, reduce water evaporation from the skin

--- for its occlusive properties Good penetration, best use on dry scaling lesions Leaving distinct residue that imparts a greasy feel an d a

shiny apprearance, discolor clothing For protection on diapers skin rash and mouth ulcers CI : acute inflammation with exudates, hairy area, and

intertriginosa Do not absorb water so it is not used for water

soluble drugs

b. Hydrophilic ointment base- Vehicle used lanolin anhydrous and

petrolatum hydrophilic.- Usage: lubrication, emollient, protection- Sticky and washable- It is used for water soluble drugs

c. Cream W/OComponents: it is an emulsion water in oil with less

than 25% of water It contains more than 1 insoluble liquid in other

liquid Less sticky, feel cool and soothing when applied

and dissappear shortly after application Its penetration is not as good as ointment Easy to be applied, less water evaporation, has

cooling effect.

d. Cream O/W

Components: it is an emulsion of oil in water with 31 – 80% water

Excipient: glycerin, propylenglycole, polyethyleneglycole to reduce dryness

Non sticky, washable, easy to be applied After applied water phase will be evaporated and

drugs on small parts of water in oil will be deposit

e. GEL/Jelly – water soluble basis

Applied easily and dissappear without visible residueJelly (cellulose substance and its derivates)

Clear, easy to be applied, washable, and can be used scalp and hairy area of the trunk where epidermis is thick

It leaves layer on the skin Less occlusive, alcohol and propylene dry

easily and cause irritation Have a high polipropylene glycol content

f. PastaComponents: It contains powder more than 50% dan hydrocarbon

ointment or emulsion water in oil. Usage:

Protection Drying Impermeable barrier, protection, or sun block

Less occlusive, more dry than ointment

a. SolutionUsage: soaking, compress

Opened compress: cleaning, emollient, drying, cooling Closed compress

Example:■ Salicylic acid 1%: astringent, weak antiseptics■ Potassium Permanganate 1/5000,1/10000: astringent, antiseptics■ Rivanol 1%: astringent, antiseptics, deodorant

b. Suspension (lotion) A liquid preparation that leave minimal

residue Application to the skin → cool for water

evaporation Easy to be applied, give the hair matte,

shiny It is effective to dry wet skin It forms sedimentation, shake before used Predominantly alcohol, Propylene glycol,

O/w emulsion

a. Topical aerosol Solution, suspension, emulsion, and foam in

propellant (mixture in nonpolar hydrocarbon). Deposit drugs in thin layer Non irritative to the skin It causes abrasion and pain.b. Foam In emulsion and foaming agent (surfactant), Solvent (example: water, ethanol), and

propelant. Foam with alcohol leaves residue Rapidly melt in dense hair-bearing areas Appears similar to gel vehicles in their ability to

release the active ingredient.

Topical therapy are a mainstay of dermatology treatment An understanding of

Interaction Drug’s concentration-penetration- availability- treatment of diseased skin allow physicians to maximize both efficacy and tolerability of topical therapy

Local and systemic toxicities allows selection of appropriate, safe therapy and minimize unwanted effects

Appropriate selection of topical agents and patients education on proper use can optimize therapeutic outcomes

Be faliliar with all the acharacteristics of the topical agent prescribed

Wolff, K;bGoldsmith, L; Katz,SI; et.al. editors; 2008, Fitzpatrick’s Dermatology in Medicine 7th edition, Mc Graw-Hill Company, p. 2091-2096, 2102-2121,2130-2142

Trozak,DJ; Tennenhouse, DJ, Russel, JJ; 2006, Dermatology Skills for Primary Care An Illustrated Guide, Humana Press Inc, Totowa New Jersey, p. 37-46

A 9 -month-old infant presents with an intensely pruritic generalized atopic dermatitis with multiple areas of excoriation and lichenification on the flexor side of the upper arm. The eruption spares only the diaper area, the palms, and the soles. Most skin regions are dry and fissured.Desired Outcome: What are the treatment goals for this patient?•What feasible pharmacologic alternative available to manage this patient’s pruritus and atopic dermatitis?

1.Should you treat this patient with topical steroid, and if so, what type of topical steroids and what kinds of preparation are available in Indonesia? 2.What treatment regimen is best suited for this patient?3.What efficacy and adverse effects monitoring is needed for the management strategies you recommended?4.How would you inform the patient’s caregiver about the treatment regimen to enhance compliance and ensure successful therapy?5.Write two prescriptions for this patients in two different dosage forms (branded products readily available in the market and active drug with appropriate vehicles)

•Should you apply occlusive dressings in this patient over the affected areas, and if so what type of occlusive dressings?•Should you treat this patient with an emollient, and if so, why?

Lembar resep latihanDr. SIP :IDI …………………….Jl Praktikum Farmakoterapi, 2, Denpasar(0361)234567

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