Routes of administration and dosage forms Flashcards
How can we deliver drugs to the body?
-oral: swallowed
-sublingual/buccal
-topical
-transdermal
-rectal
-vaginal
-inhalation
-IV
-IM
-SubQ
Why are there different forms of drug delivery to the body?
-drug properties
-onset of action
-patient acceptance
-ease of use
-cost
What route of administration is convenient and often the cheapest?
oral (po) - swallowed
What are the absorption characteristics of the oral route?
-slow absorption
-absorption primarily occurs in intestines
-subject to first-pass effect
-gastric emptying and GI motility important
What can be added or medications taken orally to protect the stomach and the drug?
a coating
What is the first-pass effect?
medication goes into liver where it is metabolized and broken down some before it enters blood stream–less % goes into bloodstream than what initially went in
What are the different formulations of substances that can be taken via the oral route?
-tablets
-capsules (soft gel caps/hard caps)
-ODT (orally dissolving tablet)
-liquids
-lozenges
What are the different types of liquids that can be taken via the oral route?
-suspensions
-elixirs
-syrups
-solutions
What type of liquid is created when a powder and liquid are mixed together?
suspension
What type of liquid contains alcohol and usually isn’t given to kids?
elixirs
What type of liquid is heavily sugared?
syrups
What type of liquid is when a liquid is added to powder to create a substance that doesn’t separate?
solution
What type of route of administration can a drug be taken that has a delayed ore extended release?
oral (po)
What are the characteristics of delayed/extended release substances?
-slow, uniform absorption over an extended period of time
What are delayed/extended release substances great for?
drugs that have a short half-life
What are the advantages of delayed/extended release medications?
-improved compliance
-lower peak levels = less side effects
What are the disadvantages of delayed/extended release medications?
-dosage from failure/dumping
-inappropriate administration (cutting/crushing)
-cost
What is the route of administration where the drug is placed under the tongue (SL) or between the cheek/lip and gums?
sublingual (SL) and buccal
What does the sublingual (SL) and buccal route of administration avoid?
first-pass effect; direct absorption to systemic venous circulation
What type of onset do sublingual (SL) and buccal drugs have?
quick onset
What is the route of administration where the drug is applied to the skin or mucous membrane (eye, ear, nose, throat, vagina)?
topical
What are topical medications used for?
local effect
What are generally not a concern for topical medications?
systemic effects
What is the route of administration where the drug is applied topically and is intended to produce a systemic effect?
transdermal
What does transdermal route of administration avoid?
first-pass effect
What are the considerations when it comes to using transdermal medications?
-skin is tough to penetrate-absorption will be slow
-drug must reach capillary bed to be effective systemically
-degree of absorption depends on lipophilicity of drug, surface area exposed, presence of abrasion, occlusion, vehicle
What type of route of administration has a partial, not full, avoidance of first-pass effect?
rectal (pr)
When medications are taken rectally, the absorption is often what?
incomplete or irregular
Rectally administered medications may be what?
systemic or local
Rectally administered medications would be good for who?
sometimes kids, people who can’t swallow, someone throwing up, someone in a coma
What does the vaginal route of administration avoid?
first-pass effect
What becomes problematic when taking medications vaginally?
retaining dosage forms due to vaginal fluid clearance
Why are some medications given vaginally?
it has good blood supply and surface area
In what route of administration is the drug quickly and well-absorbed due to the lungs having a large surface area and has an immediate effect?
inhalation
What does the inhalation route avoid?
first-pass effect
What is a great why to deliver medication directly to the lungs and is sometimes used sytemically?
inhalation
What are the characteristics of intravenous (IV) route of administration?
-100% bioavailability
-fast onset
-bolus or continuous dosing
-not appropriate for patient self-care
What does 100% bioavailability mean?
the fraction of a dose that reaches systemic circulation is unchanged (not getting broken down initially)
What is the only true 100% bioavailable course of administration?
Intravenous (IV)
What does bolus mean?
one time
What does intramuscular (IM) administration avoid?
firs-pass effect
What must the drug permeate for systemic absorption for intramuscular (IM) administration?
capillary walls (increasing blood flow will increase absorption)
Who will show unexpected results when taking a medication via IM route?
obese or emaciated patients
What is the absorption rate of IM medications?
absorption is fast; may be slowed by suspending in oil, using microspheres
What route of administration has a slower absorption than IM?
subcutaneous (SC, SQ) because you are putting it in the skin, not directly into the muscle, so it has longer to travel)
What does the subcutaneous route avoid?
first-pass effect
The absorption rate of subcutaneous medications may be altered by what?
-particle size
-protein complexation
-addition of vasoconstrictors
-pH
What are other routes of administration?
-intrathecal
-intraosseous
-intra-arterial
What route delivers drug right to the CNS?
intrathecal
What route delivers drugs in to the bone where the bone marrow drains into venous system and is seen often in the ER and peds where access may be difficult?
intraosseous
What route is uncommon, requires special training, is when there is a quick withdrawal of needle and immediate pressure is required?
intra-arterial
What can be used if patent has no patent venous access?
intra-arterial
What carries the risk of capillary bed destruction and loss of perfusion possible?
intra-arterial
What route is appropriate for vasodilators?
antra-arterial
What is floxuridine an example of where the antineoplastic is delivered directly to the liver vis the hepatic artery?
intra-arterial
What are the pros of parenteral administration?
-better absorption
-quick or immediate onset
-IM and SC can be modified to create slow/delayed onset
What are the cons of parenteral administration?
-training
-cost
-comfort
-sterility
-equipment
What should you look at when choosing a route and formulation?
-efficacy (local/systemic; general patient health)
-side effects
-desired onset and length of therapy
-cost
-compliance issues (lifestyle, acceptability, ability to administer drug)
What is the drug discovery process
- target discovery
- chemical library screening
- lead optimized
- pre-clinical animal studies
- clinical trials
- market entry
When you think you have invented a drug, you need to administer it to how many different animal species?
2
The two different animal species used in a study are typically what?
one rodent, one non-rodent
What are you looking for in animal studies of a new drug?
general toxicity- increase doses until lethal
After looking at general toxicity of a drug in animal studies, what do you look at?
subacute (2-4 weeks) and chronic (6-24 months) toxicity testing
What has to be further investigated in animal studies of a new drug?
any negative effects
After you do animal studies of a new drug, you can submit what?
IND (investigational new drug)
How many days does the FDA have to evaluate applicants who submitted an IND?
30 days
If your IND is approved, you can begin working on what?
clinical trials
What occurs in phase I clinical trials?
-first trial in humans (10-100 people)
-normally healthy volunteers, occasionally patients with rare/advanced illnesses
What is tested in phase I of clinical trials on humans?
safety and tolerability
What occurs in phase II clinical trials?
-first trial in patients (50-500 people)
-patients with illness
What is being tested in phase II of clinical trials on patients?
efficacy and dose range
What occurs in phase III clinical trials?
-large scale multi-site (few hundred to few thousand people)
-patients with illness
What is being tested in phase III of clinical trials in patients?
-confirms efficacy, compare to older therapies, continue to evaluate safety
After phase III of clinical trials, what is submitted?
NDA (new drug application)
After you submit an NDA and it is approved, what do you move onto?
phase IV trial where it is the post-marketing surveillance (thousands of patients)
When is a patent for a drug usually started?
around time of IND
How long does a patent last?
20 years
How long is usually left in a patent when a drug is officially approved?
10-14 years
What act prohibited mislabeling and adulteration of food and drugs?
Pure food and drug act of 1906
What act established regulations for use of opium, opioids, and cocaine?
Harrison Narcotics act of 1914
What act make it so drugs were tested for safety and purity?
Food, drug, and cosmetics act of 1938
What act made it so companies had to provide proof of efficacy as well as safety for new drugs?
Kefauver-harris amendment 1962
What act amended food, drug, and cosmetics act to establish standards for dietary supplements but not to allow FDA to apply same standard as for drugs?
dietary supplement and health education act of 1994
