Pharmaceutics Flashcards
Levodopa
Prodrug of dopamine
Cross BBB
Metabolized to dopamine via side of blood brain
Given with dopa decarboxyclase inhibitor (carbidopa) to prevent metabolism until after crossing BBB
Used for parkinsons disease
How is Levodopa used for parkinsons disease?
By metabolizing to dopamine supplements the low endogenous levels of dopamine to treat parkinsons disease symptoms
Levedopa different formulations
Levodopa dispersible / orally disintegrated formulations - Early morning on empty stomach , high absorbtion of stomach
Levodopa modified released - useful for effects of nocturnal immobility and rigidity associated with end of dose deterioration ( not for initation therapy)
Exelon transdermal (Rivastigmine)
Rivastigmine is a medication that belongs to a class of drugs known as cholinesterase inhibitors used for paki son and alzheimers disease (dementia side effects)
The medication works by inhibiting the breakdown of acetylcholine and butyrylcholine, chemicals that are important for memory and cognition, which are often depleted in people with dementia.
Why is Exelon patch (Rivastigmine) as transderamal?
through the skin directly into the bloodstream over a prolonged period, providing a more consistent level of medication than oral forms. In the context of Parkinson’s disease,
ADHD / ADD treatment
Immediate release- 2-3 times, compliance issues, abuse potential, social stigma at school
Extended release - single dose, better social acceptance issue: behaviour less well controlled later im day.
Extended release tablets pharmacokinetics
Achieve therapeutic plasma conentration of drug remains constant within therapeutic range for a satisfactory aamount of time
Glioblastima multiforme GBM
Rapidly progressive brain cancer
Brain tumour therapy challenges
Carmustine - chemo molecule with a short plasma half life (12 min) and extremely toxic
Conventional injection into blood requires drug cross BBB to reach brain
Radiation needs to wait 14 days after surgery (may increase size of tumour)
Explain properties of brain tumour anticancer drugs ( Carmustine)
Biodegradable poly(anhydride) polymer wafer implant that releases drug at site of tumour
Wafer degrades by surface erosion
Explain how polymers degrade
Solid poly(anhydrides) degrade to soluble acids in water over days to weeks (depends on polymer composition).
What does solid poly (anhydrides) do?
Allows medicines to be biodegradable
Has a very liable group (anhydride) , in contact with water the polymer degradation begins immediately and is fast reaction
Monomer hydrophobic slows down penetration of water into the bulk wafer
