Drug Delivery Systems Flashcards
What are the 4 main types of drug delivery?
Oral
Injection based
Transdermal
Carrier-based
Different drugs
Tablets, solutions/suspensions, Ointments and creams Inhalation Injections Suppositories Pessaries
Dosage regime factors?
The Dose of drug to be given
Frequency of administration
Timing of administration
Choosing a dosage
Find out recommended dosage (BNF/BNFC)
Impaired renal function? Hepatic function?
Consider age and weight
Consider disease
Consider drug toxicity
Starting dose - increase until desired result is achieved.
Oral medication
Via GI tract
Buccal
Sublingual
Oral
Rectal
Solutions
Can be expensive
Suspensions
Dispersions of coarse particles in liquid phase
Are tablets stable?
Yes, highly stable
Enteric coated tablets
Coating only breaks up when reaches a more alkaline environment. (Protects drug from stomach acid)
Prolonged release formulations
Improve compliance, much less scope to forget
Cannot swap from one to another *
Parenteral preparations
Intramuscular injections
Pro drugs
…
Sublingual administration
Dissolve slowly under younger
Most common - GTN for angina
What are very commonly used in France?
Suppositories
Suppositories, creams and liquids
Useful in young and old and those who cannot swallow
What are pessaries?
Drugs used through vagina route
Injection-based
Sub-cut
Sub-dermal
Intramuscular - muscle can start to disintegrate
IV administration used when?
Rapid onset of action is required,
Careful control of plasma levels required
Slowly given - to prevent toxic effects
Continuous infusion
Transdermal delivery
Adhesive patches
Diffuses by percutaneous absorption - goes into systemic circulation
Percutaneous
Creams
Ointments
Skin patches
Inhalation
Advantage - drug direct, rapid effect
Disadvantage - patient education necessary
What is an inhaler spacer?
Tube to go on end of inhaler - makes it easier for patients who are struggling with inhaler
Carrier - based drug delivery system
Micelles - vesicles, carry drug inside
Monoclonal antibodies - linked to cytotoxic agent
Liposomes - lipid layer - allows absorption
Nanoparticles -
Genetic transfer system
(GEne transfer)
Colour of tablets
Colours/ shapes/ words on can influence the effect!!
What are the three main principle mechanisms of renal drug excretion?
Glomerular filtration
Active tubular secretion
Passive tubular reabsorption
What is glomerular filtration
Flow rate of filtered fluid through kidney
What is active tubular secretion?
Transfer of materials from peritubular capillaries to renal tubular lumen
What is passive tubular reabsorption?
Solutes and water removed from tubular fluid and transported into blood
What is first pass metabolism?
The metabolism of the drug before it reaches systemic circulation so effect can be unexpected
