Topical Dosage Forms Flashcards
What dosage form is used topically to have a controlled technology of release?
Patches
What is the top layer of dead, dry skin called?
Stratum corneum
_____ stratum corneum is less of a barrier to drug entry than ______stratum corneum.
Hydrated, dessicated
What is the definition of a semi-solid?
Material that acts like a solid under some conditions and a liquid under other conditions
What is the purpose of liquid-like behavior in a semi-solid?
To allow material to spread easily and without pain
What is the purpose of solid-like behavior in a semi-solid?
So the material will remain spread and not fall off the point of application
What are some advantages of topical dosing?
If treating skin directly, can minimize side effects, minimize costs (smaller drug amt), allows for repeated, easy dosing; for systemic delivery, can avoid acid of GI tract, no 1st pass metabolism, repeated and easy dosing
What are some concerns of topical delivery?
Because skin such a good barrier, few drugs can pass to systemic circulation, only a few mgs of drug can pass in a day, may need repeated applications for local effect because drug may be “cleared” from area rapidly
Why are topical dosage forms usually restricted to highly potent drugs?
Because only a few mgs of the drug can penetrate the skin in a day, and so the drug must be potent to attain useful concentrations
What are four types of topical products usually used for local treatment?
Ointments, creams, pastes, topical liquids
What type of topical product is usually used for systemic treatment?
Patches
What does occlusive mean?
Prevents movement of water from skin out into the environment (helps hydrate stratum corneum)
What is the most occlusive ointment base? The least occlusive?
Hydrocarbon/oleaginous (most), water-soluble (least)
What two ointment bases are water washable?
Emulsion and water-soluble
Which two ointment bases are not water washable?
Hydrocarbon/oleaginous, absorption
