topical formulations in dermatology pptx

Topical applications in dermatology

1. Topicals in dermatology Dr . S.Kali Raj P.G. Dermatology 1

2. Introduction Topical therapy constitutes one of the two pillars of treatment of dermatological diseases . 2

3. Topical Therapy 3 Drug can be delivered in high concentrations to skin Minimal exposure of internal organs to side effects of drugs. Advantages More time consuming . May be complicated for patients to follow instructions especially if more than one drug has to be applied simultaneously . Sometimes messy . More chances of local side effects as compared to systemic therapy. Disadvantages

4. Principle Of Topical Therapy 4

5. Factors Affecting Percutaneous Penetration FACTOR EFFECT Condition of skin barrier Traumatized skin increases penetration Thickness of stratum corneum Thinner SC- more penetration (mucous membranes, scrotum, eyelids and face) Thick SC – less penetration (nails, palms, soles) Drug formulation Drugs denaturing SC enhance penetration (alcohol, surfactants, solvents) Application method Occlusion enhances penetration - hydration, temperature of SC increased due to occlusion; washing off of the drug is delayed. But may be accompanied by increased chances of local side effects of the drug. Application of penetration enhancers Moisturizers and keratolytics (propylene glycol, urea, DMSO, salicylic acid) enhance penetration . 5

6. Factors Affecting Percutaneous Absorption Percutaneous absorption occurs by passive diffusion . Type of drug. Vehicle that carries the drug. Condition of skin. Molecular size of drug. Concentration of drug. Cutaneous vasculature (inflamed skin has increased circulation) Surface area ratio (in terms of both BSA and drug size- micronized drugs) volume 8. Vigorous massaging increases blood supply thereby increasing absorption. 6

7. Vehicle A vehicle is a substance which is incorporated into a topical preparation in order to facilitate drug delivery by bringing the drug in contact with skin. Importance of vehicle : Bioavailability of drug may depend on the type of vehicle . Drugs are incorporated in vehicle in concentrations which are maximally effective . 7

8. Beneficial Effects Of Vehicle Vehicles themselves have therapeutic effects like : Occlusion Protection Cooling Emollient effect Astringent effect 8

9. Properties Of An Ideal Vehicle Physically and chemically stable Non-irritating Non-allergenic Easily applicable Cosmetically acceptable Therapeutically acceptable Should not deactivate the drug 9

10. Various types of Vehicles and their examples 10 Lipids Petrolatum Glycerin Cetyl alcohol Stearyl alcohol Lanolin Shea butter Solvents Alcohol Acetone Ether Glycerin water

11. 11 Emulsifying Agents Cholesterol Polyethylene Glycol Sodium Lauryl Sulfate Sodium Laureth Sulfate Lanolin Stearyl alcohol Thickening Agents Bees’s wax Polyethylene carbomer

12. 12 Humectants Stabilizers And Preservatives Glycerin Propylene glycol sorbitol Parabens Glycerin Propylene glycol Chlorocresol Potassium sorbate Benzyl alcohol

13. We have just noted that some vehicles have multiple properties : Humectant Stabilizer Emollient Solvent Humectant Stabilizer 13 Glycerin Propylene Glycol

14. Factors Affecting Drug Action On The Whole 14 Drug factors Host factors Percutaneous penetration Percutaneous absorption Type of vehicle Type of topical formulation Quantity of drug Frequency of application Drug reactions Age of patient Site of application Hydration of skin Temperature of skin Abnormalities of stratum corneum Cutaneous circulation

15. Classification Of Topical Formulations 15 Liquids Semisolids Solids

16. Liquids are again classified as : Solutions Lotions Liniments 16 Aqueous Alcoholic

17. Aqueous Solutions They constitute : Wet dressings Soaks and baths 17

18. Wet Dressings They have 4 main effects : Anti-pruritic effect Vasoconstriction Cleansing effect Keratolysis 18 Open wet dressing Closed wet dressing

19. 19 Ingredients of wet dressings : Normal saline Astringents or antiseptics = Aluminium acetate Potassium permanganate Silver nitrate Acetic acid

20. Aqueous Solutions – Soaks And Baths Useful for their : Mechanical cleansing Soothing Anti-pruritic effect Anti-inflammatory action 20 Used for treating more widespread and less exudative lesions

21. Baths are of various types : General cleansing baths used to remove dirt, scaling, debris and residues of previous medications. Medicated baths containing : Sulfur Potassium permanganate Psoralen These have anti-pruritic, anti-eczematous, anti-seborrheic, anti-psoriatic properties. 21

22. Alcoholic Solutions They may be : Paints Collodion Tinctures Varnishes Sprays 22

23. Paints / Collodion Paints: Liquid preparations applied with a brush Example: Castellani’s paint May stain skin and mucosa Effective in pustular dermatoses of hand and feet Collodion: Solution of pyroxylin in ether + alcohol/acetone Hydrophobic, inflammable Leaves a film on skin after drying → Prolonged drug contact Example – Collodion Flexide : Contains: Collodion, camphor, castor oil Vehicle for: Salicylic acid, lactic acid Used for : Warts &Herpes zoster protection 23

24. Tinctures They are alcoholic solutions designed to deliver large amounts of active ingredients at a site without any undesirable cosmetic effect . Used in areas which are not usually easily irritated like scalp . Light and heat sensitive. Active ingredients may be : Corticosteroids Keratolytics Antiseptics – Tincture iodine Prolonged use of tinctures may cause dryness . 24

25. Varnishes Special type of tinctures, in which alcohol, after evaporation, leaves a thick film , for example, nail polishes used to deliver antifungals in onychomycosis. Eg: Nail lacquer 25

26. Sprays These are used to deliver droplets of a drug over a wide surface area . After evaporation of the carrier, the drug is left behind . 26

27. Lotions (Liquid Formulation) Basically they are either solids or liquids dissolved in a liquid. 1. Solid in liquid lotion (shake lotion) Eg: Calamine lotion 2. Liquid in liquid lotion(o/w or w/o) Eg: Venuxia max 27

28. Calamine lotion Calamine lotion is a topical skin protectant and antipruritic (anti-itch) suspension commonly used for itching , skin irritation , and mild rashes 28 Ingredients Calamine (5–15%) Zinc oxide Glycerin Bentonite or Kaolin Liquefied phenol Purified water Alcohol

29. Liniments Also called as balms They are : Non-alcoholic solutions of drugs in oil Alcoholic solutions of soaps. Similar in viscosity to lotions . Unlike lotions, they have to be rubbed into the skin with friction . Used as : Analgesics Anti- pruritics Emollients Counter-irritants Astringents 29

30. Semi-solid Formulations They are classified as : Creams Ointments Gels pastes 30

31. Creams They are semi-solid 2-phase emulsions where one immiscible liquid is dispersed in another. Creams may be lipophilic or hydrophilic depending on the w/o or o/w respectively . Ambiphilic creams, on the other hand, have equal amounts of water and oil. 31

32. Lipophilic Creams water in oil emulsions . Eg: cold creams In chronic conditions : Psoriasis Atopic dermatitis Hypertrophic LP. 32

33. Hydrophilic Creams oil-in-water emulsions . Eg: vanishing creams Indicated in non-scaly subacute and chronic conditions. Contraindicated in dry skin conditions – ichthyosis and atopic dermatitis. 33

34. Ambiphilic Creams Equal amount of fat and water . Can be mixed with additional water or oil. Used in various skin types and in subacute to chronic dermatoses. However, not useful in oozing dermatoses or very dry skin. No preservatives needed, since they contain propylene glycol . 34

35. Barrier Creams They contain water repellents such as : Dimethicone Which protect the skin against : Irritation Incontinence Repeated hydration Used in : Diaper dermatitis Decubitus ulcers 35

36. Ointments They are semi-solid formulations Soft to firm Greasy Single-phase preparations in which liquid and solid substances are dispersed. 36 Hydrophobic Hydrophilic Water absorbing

37. Hydrophobic Ointments They are single-phase water-free ointments. Not washable with water. Examples : Hard paraffin Semi-solid paraffin (yellow and white petrolatum) Liquid paraffin. 37

38. Water Absorbing Ointments 38 Water-in-oil Oil-in-water Less occlusive properties than hydrophobic ointments. For dry skin and chronic diseases. More spreadability . Hence used in hairy areas and for shorter periods of application on normal or oozing skin. Do not occlude the skin – minimal maceration. To be applied on moist skin .

39. Hydrophilic Ointments They are medications in a base containing polyethylene glycol which acts as a lubricant and contain necessary preservatives like parabens or cresol . Not just hydrophilic, they are also hygroscopic Used to prepare anti-septic and anti-fungal ointments. But their use is limited as they are incompatible with large number of ingredients. 39

40. gels Soft Translucent to transparent in appearance. Liquefy upon contact with skin and form greaseless film upon drying . 40

41. 41 Oily gels Hydro gels Prepared from liquid paraffin or fatty oils . Suitable in : Hyperkeratotic Papulosquamous Atopic dermatitis Ichthyosis Contain : water Glycerin propylene glycol cellulose derivative. Suitable in : Oily skin Mucosal surfaces.

42. Pastes Prepared by incorporating fine powdery materials into an ointment base. Zinc oxide Aluminium oxide Titanium oxide Starch Talc. 42

43. Drying Paste Contains powder in liquid . They soothe and dry the skin. Used along with dressings as paste bandages . 43 EPSOM SALT

44. Powders Used to dry or cool the skin by : increasing evaporation Reducing friction Anti-pruritic medication . 44 Inorganic powders : Zinc oxide Titanium dioxide Talc Bentonite or calamine Organic powders : Starch Zinc stearate

45. Powders Contd … Used to deliver antibiotics ( combination of polymyxin B, bacitracin and neomycin ) or antifungals. Commonly used in intertriginous areas and feet . Used to treat erosions and ulcers . prolonged use may cause sensitization (ACD) When applied on wounds, talc has occasionally caused granuloma ( talc granuloma ). 45 Disadvantages

46. Tapes and plasters Delivery system used to keep active ingredient in close contact with skin to enhance penetration . Composed of flexible glue (lead salts of long chain fatty acids) Examples : corticosteroids and salicylic acid plasters for warts and corns. However, they may cause maceration and occasional irritation . 46

47. References IADVL Textbook of Dermatology 47

48. Thank you