drug delivery systems Flashcards
what are the 4 main groups of drug delivery?
- oral
- injection based
- transdermal
- carrier based
carrier based drugs
drugs are attached to substrates eg. liposomes or nanoparticles
forms in which drugs are given to patients
tablets or capsules solutions or suspensions ointments or creams inhalation injections suppositories pessaries
types of tablets and capsules
regular, modified release, prodrugs, enteric coated
what determines the drug delivery system used?
- the dose of drug to be given
- the frequency of administration
- the timing of administration
what are the factors that affect a dosage regime?
- find the recommended dose in the British National Formulary
- Is there impaired renal function
- Is there impaired hepatic function
- Consider age and weight
- Consider disease to be treated
- Consider drug toxicity
- Give a starting dose and increase dose to achieve the desired effect
which groups of patients are given solutions and suspensions?
young
elderly
patients with difficulty swallowing
what are the advantages of tablets and capsules?
- convenient to use
- dose is very accurate
- reproducibilty
- drug stability
- ease of mass production
what are enteric coated tablets?
tablets whose disintegration is delayed until the tablet is in the small intestine
why are tablets enteric coated?
- to protect the drug from the stomach
- to protect the stomach from the drug
what are the advantages of prolonged or delayed release formulations?
- most disorders require prolonged therapy
- maintains drug levels within a therapeutic range
- reduces the need for frequent dosing
- compliance is improved
- improved nursing and doctor compliance
what are the advantages of prodrugs?
- the duration of action is prolonged
- degradation is avoided in the gut
what is the main advantage of buccal and sublingual administration?
avoids first pass metabolism so is ideal for that are rapidly metabolised by the liver before they reach the systemic circulation
advantages of the rectal route?
- bypasses first pass metabolism
- can be used for patients who are unable to swallow
when are drugs given intravenously?
rapid onset of action is needed
careful control of plasma levels is required
a drug has a short half-life
