routes of administration Flashcards
how do we w develop medication
- what is the api - active pharmaceutical ingredient
- what and where are we trying to treat
- what would be the best route of administration
- what might be the suitable dosage ( elderly or paediatric- child)
systematic vs local delivery
systematic
- delivery of the drug to the site other than where it is applied - where it passes through the systematic circulation for example paracemtoml
local
- delivery of the drug directly to the intended site of action - eye drops
enteral vs parental delivery
parental
completely bypasses the digestive system eliminating the effect of of first pass metabolism
enteral
it uses the digestive system including the mouth, stomach, small intestine and anus
topical route
- topical to the surface of the body
- may be local or systemic
- some topical routes are mucosal routes of administration
- mucosal - wet surfaces of the body which secrete mucous
oral route of administration
- most popular and confident route
- these drugs can survive the acid of the stomach and enzymic attack
- they can be absorbed across gi membranes
- survive the liver
- tablets and capsules are most common for adults
- liquid preparation for children or patients unable to swallow dosage forms
- systemic or local delivery
what is the oral drug delivery
- passage through the stomach and intestine
- gastric emptying, eating and volume of contents
- provides many and varied barriers to drug absorption
- passive, carrier- mediated and specialised modes of absorptive transport
- clinically convent
what are the advantages and so advantages of oral
advantage
- most common and widely accepted
- safe, confident and economical then a parental route
- self administration
- slow release may be available to extend duration of action
- drugs can be formulated in such a way they are protected from acid
disadvantage
- vomiting
- destruction of drug due to ph, bile enzyme in gi tract
- variable absorption across the gi tract
- patient co operation required - grumpy kids
- first pass metabolism for some drugs limits their bioavailability
parental drug delivery
advantage
- by pass of first pass hepatic metabolism
- rapid and predictable absorption
- quick and convenient, range of dosage forms and rotes
- devices and formulations allow good control of drug delivery
disadvantage
- patients do not like injections, needle phobia
- complicated and costly manufacture and or reconstitution
- difficult to self medicate
- need skilled people to administrate
baccal and sublingual drug delivery
application to cheek or under tongue
adavantages
- easily acccesible
- avoids hepatic and fist pass metabolism
- avoids gi degradation
- high degree of vascularisation
- high patient acceptability
- option to remove formulation
disadvantage
- small surface area
- low fluid volume
- can be swallowed
- patient controls drug release
- patient controls drug release and rention
- can be difficult to retain
- palatability can be an issue
pulmonary drug delivery
involves inhalation into the lung
aerosols
advantage
- quick action
- smaller dose required than is needed for oral IV delivery
- reduction in systematic side effects
topical and transdermal
topical = delivery to the bitty surfed
transdermal = system delivery using the skin as rate limiting mechanism siam
advantage
- high patient compliance
- potential for moisturistaion and occlusion
- control of drug entry into systemic circulation
- avoidance of hepatic first pass
disadvantage
- low permeability
- complex formul,action
- visible - such as a contraceptive patch
nasal drug delivery
it interacts with the nasal mucosa
route to the brain
usually local for allergic reactions for example
but has systemic effects due to the high degree of vascularisation and high permeability
advantages
- avoids gi and hepatic first pass effect
- fast onset of action
- ease of administration, non invasive and self medication
- ease of use in patients with nauseas and vomiting
disadvantages
- absorption time limited by mucociliary clearance
- low absorption surface in comparison to intestinal mucosa
- enzyme activity in nasal mucosa
- variability in the absorption in case of chronic alterations of nasal mucosa
vagibala drug delivery
delivery into internal vagina
local delivery = antifungals
systemic delivery = hormonal contraceptives
adavantages
- bypass of hepatic first pass metabolism
- treatment of local conditions
- target the ovaries and uterus
- pre exposure prophylaxis
disadvantage
- gender specific
- stigma associated with administration
- irritation and microbial imbalance may be issues
rectal drug delivery
majority of blood from the rectum makes it way to the hemorrhoidal veins
superior hemorrhodial vein drains into the portal system (liver)
inferior and middle hemorrhoidal veins bypass the liver - which is the first pass metabolism
local, systemic and diagnostic delivery routes
adavantages
- rapid onset action
- nausea, vomiting, post operatively
- local treatment
- avoids first pass metabolism
- if drug is not suitable for oral admin
disadvantage
- patient compliance
- slow or in complete absorption from suppositories
- development of procitis
ocular drug delivery
eye permeability low
topic deliver common
low rendition
targeting inner eye difficult
adavantages
- rapid onset action
- reduced systemic side effects
- smaller amounts of drug required
- ability to treat inner eye
disadvantage
- patient compliance
- sensitivity of eye
- limited by small delivery volumes
- low epeithelial permeability
- short residence time
- sterilisation required
