Clinical implications Flashcards
What is the objective behind the design if dosage forms?
Safe and effective medicines
Predictable and reproducible therapeutic response
What is bioavailability?
the extent a substance or drug becomes completely available to its intended biological destination
the extent and rate at which the active moiety (drug or metabolite) enters systemic circulation, thereby accessing the site of action.
What is maximum safe concentration/minimum toxic concentration? What is minimum effective concentration (MEC)?
MSC/MTC
- the concentration of drug in plasma above which toxic effects are produced.
MEC
- the minimum plasma concentration of a drug needed to achieve sufficient drug concentration at the receptors to produce the desired pharmacologic response
= minimum concentration at which pharmacologic response is first observed
What is onset of action? What is duration of action?
onset of action
- the LENGTH OF TIME it takes for the EFFECT(S) of a drug to become noticeable after being taken
duration of action
- the LENGTH OF TIME it takes for the EFFECT(S) of a drug to LAST after being taken
What is therapeutic index?
the range of doses at which a medication is effective without unacceptable adverse events.
What is bioequivalence?
two drugs with identical active ingredients or two different dosage forms of the same drug have similar bioavailability and produce the same effect at the site of physiological activity
What are the advantages of the oral route?
mos convenient and safest
can be used to achieve either systemic or local effects
What are the disadvantages of the oral route?
relatively slow onset of action
irregular absorption due to interaction with food, GI secretions, digestive enzymes and first pass metabolism
What are buccal and sublingual delivery?
buccal - involves placing a drug between your gums and cheek, where it also dissolves and is absorbed into your blood.
sublingual - involves placing a drug under your tongue to dissolve and absorb into your blood through the tissue there.
What are the advantages of the buccal/sublingual route?
avoids first pass effect
- is suitable for drugs metabolised in the liver or unstable in the GIT
fast absorption and onset of action
- due to abundance of blood vessels
- useful in emergencies, for nausea and vomiting
easy administration and termination
lower inter-subject variability as compared to transdermal patches.
What are the layers of the skin?
epidermis
- outermost layer
- made up of squamous stratified epithelium that protects against microorganisms invading underlying tissue and/or protection against water loss
dermis
- middle layer
- made up of connective tissue, capillaries, nerve endings, and hair follicles
- contains different glands, including sebaceous glands
hypodermis (subcutaneous tissue)
- innermost layer
- mostly made up of fat, connective tissues, larger blood vessels and nerves
What is the difference between drug in adhesive (matrix) transdermal patches and membrane moderated trandermals patches?
drug in adhesive (matrix) transdermal patches
- can be cut
- medicines are embedded in a solid adhesive matrix and release is proportional to the surface area of the patch on the skin
membrane moderated transdermal patches
- cannot be cut
- cutting destroys the rate-controlling ability of the membrane and can lead to delivery of the entire drug
What are the advantages of suppositories?
useful for patients who are nauseous or vomiting
small and large doses could be administered via this route
duration of action can be controlled by using the suitable formulation
hepatic first-pass elimination Is partially avoided
drugs liable to degradation in the GI tract can be administered via this route
What are the disadvantages of suppositories?
patient acceptability and compliance is poor especially for long term therapy
suppositories can leak
insertion of suppositories may be problematic
drug absorption from suppositories is slower than oral or intravenous administration
What tablet forms should not be split?
extends release
enteric coated
sugar/film coated
