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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?
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