pharmacology Flashcards
in topical drugs what drives delivery
it’s passive driven by diffusion
what is fick’s law
rate of absorption is proportional so SA and inversely proportional to thickness
should topical drugs be lipophillic or phobic
lipophillic/ hydrophobic
what are vehicles, what would you put in a hydrophobic vehicle
creams, gels, ointments etc with dissolved concentration of the drug, lipophillic drug
what is better for maximising movement of a vehicle
solbulised > undissolved
what are excipients
enhance solubility - put clingfilm on to avoid water loss
why is excess nondisolved drug added to vehicles
increased duration and provide constant rate of delivery
what 4 factors affect absorption
site of application (thickness and permeability), hydration, drug conc, vehicle
in subcut route where is the drug injected and how does it enter the blood stream
subcut adipose, enters capillaries or lymphatics, slow absorption from poor vascular supply
is subcut first or second pass metabolism
avoids first pass
what is transdermal drug delivery and examples of suitable drug criteria
adhesive patch to dermis. LMW, lipophillic, potent, short half life
what transdermal patched are available
GTN, nicotine
give an example of s subcut drug
adrenaline, insulin
what are creams and what are the pros and cons
semi solid emulsification of water and oil with preservatives, cooling and moisturising, non-greasy
what are ointments and what are the pros and con
semi solid grease with high lipids but no preservatives, limit transdermal water loss, greasy
what are lotions and what are the pros and con
liquid formulations suspended in alcohol or water, can sting, used for dry areas eg scalp
what are gels and what are the pros and con
semi solid aqueous solution, hairy areas and the face
what are pastes and what are the pros and con
semisolids made up of fine powdered materials eg ZnO, cool and hydrating, difficult to apply
what are emollients
used to rehydrate dry/ scaly skin (eczema and psoriasis ), apply frequently
when is wet wrap therapy used
very dry (xerotic skin)
what qualities to steroids have
vasoconstrictive, anti-inflam, anti proliferative, lipophilic
name topical steroids from least to most potent
hydrocortisone, eumovate, betnovate, dermovate
what conditions are topical steroids commonly used for
eczema, psoriasis, lichen planus, keloid scars
what are side effects of steroids (7)
thin skin, purpura, stretch marks, steroid rosacea, telangestasia, dermatits (acne), tachyphylaxis
