3. VEHICLES:
medications are incorporated into inactive substances called
vehicles that bring the medications directly in contact with the
skin .
-->An appropriate vehicle maximizes the ability of drug to
penetrate the skin.
E.g.
a lipophilic drug moves readily into the epidermis if it is in an
aqueous vehicle.
4. OINTMENTS :
semisolid ,composed of lipids like soft paraffin,wool fat, wax etc
single phase (fatty ointment without water content) or
two phase system (water droplets in lipid).
require fewer preservatives than other vehicles.
Disadvantage-: not be used on acutely inflamed lesions or hairy areas .
CREAMS :
semisolid emulsions containing both lipid and water,
either of lipid droplets in water (aqueous creams) or
water droplets in lipid (oily creams).
intended to be rubbed till they vanish.
FORMULATIONS
5. GELS :
transparent,colorless emulsion containing propylene
glycol and carboxypolymethylene.
it liquifies on contact with skin and dries as a thin
non-occlusive film.
Acceptable in hairy areas and scalp.
e.G clear gel,glofa gel etc
SOLUTIONS :
predominant content is water, whose cleansing,
drying, cooling effect provide major therapeutic effect.
soothe and cool the inflammed skin, soften crusts,
help in cleansing wounds.
E.g. silver nitrate ,burrow’s solution , acetic acid etc
6. PASTES :
semisolid preparations containing high concentration of finely powdered
materials such as zinc oxide or starch.
2 types-:
1.Protective pastes that are greasy
2.Drying pastes that are water-miscible.
e.g triamcinolone oral paste
POWDERS :
absorb moisture and help in cooling .
organic or inorganic.
1.organic powder include starch and zinc stearate,
2.inorganic powder include zinc oxide, titanium dioxide and
calamine.
USE : in intertriginous areas, tinea pedis etc
e.g. clotrimazole dusting powder
7. PAINTS :
either aqueous, hydroalcoholic or alcoholic
applied with brush and allowed to evaporate
useful in intertriginous area
e.g.castellani’s paint
COLLODIONS :
liquid preparation consisting cellulose nitrate in
organic solvent
used to apply salicylic acid and lactic acid to
warts.
8. AEROSOLS :
contains the drug in an emulsion with foaming
agent,
solvent and propellant.
Advantage : ease of application especially on hair
bearing area.
Disadvantage : expensive and non ecofriendly.
e.g. steroid aerosol spray
LOTIONS:
suspensions of powder in water .
spread easily over large surface areas
USE : in superficial dermatoses.
E.g calamine lotion
9. NEWER FORMULATIONS
MICROSPONGES :
It consists of porous microspheres that provide sustained release of drug.
Adv-reduces irritation.
e.g. antidandruff shampoos
MICROGELS :
These are polymers that enhance stabilization and penetration of drugs and
diminish irritancy.
e.g. tretinoin gel
LIPOSOMES :
These are uni-multimellar spherical shells of phospholipids in aqueous
medium that may enhance percutaneous absorption.
e.g. liposomal amphotericin B
10. NIOSOMES :
non-ionic surfactant based liposomes which are
structurally similar to liposomes.
Adv- biodegradable ,
relatively nontoxic,
more stable, inexpensive.
e.g. niosomal methotrexate gel
TRANSFEROSOMES :
a drug delivery technology based on highly deformable,
ultraflexible lipid vesicles that penetrate the skin surface when
applied topically.
Adv- unique as it can accommodate hydrophillic , lipophic
and amphiphilic drugs.
e,.g. terbinafine transferosomes
11. ETHOSOMES :
soft , malleable vesicles composed of ethanol
phospholipids, and water.
enhances penetration by dissolving the
intracellular bilayer in stratum corneum.
Adv : greater penetration into deeper layers of
skin.
e.g. acyclovir, minoxidil
12.
13.
14. FOAMS :
well accepted but costly
new foams have ability to deliver the active
drug at increased rate because it uses “rapid
permeation” pathway for delivery of drug.
e.g. clofoams, betafoams.
16. FAVOURABLE FORMULATIONS
Depending on nature of dermatosis:
Wet or oozy skin condition: cream, lotion,
drying pastes
Inflammed skin: wet compress, soaks followed
by creams and ointment
Dry scaly skin : ointments , oil
cracks and sores : bland application
17. Depending on site :
palms and soles: ointment or cream
skin folds : cream or lotion
hair areas : lotion,solution,gel ,foam
mucosal surface: nonirritating formulations
18. QUANTITY OF APPLICATION
The guide to the quantity of a topical medication to
be applied is provided by the concept of
1. FTU finger tip units and
2. rule of hand
One FTU weighs approx 0.49g in males
And 0.43g in females.
Rule of Hand : area covered by 4 adult hands
including digits = 2 FTUs
19. Comprised of copper containing pthalocyanine
ring linked to 4 isothiouronium groups – strong
bases - account for cationic nature of the dye
Sulfate and carboxylate groups of
proteoglycans ionised at pH 2.5 and carry a
negative charge
Sialo- and sulfo mucins also reactive at pH 2.5
So, they stain with alcian blue at pH 2.5
Neutral mucins are not reactive with alcian
blue
Apperance – metachromatically purple