Topic 2 - Routes of Absorption Flashcards
Drug
Any substance/mixture of substances manufactured, sold, or represented for use in diagnosis, treatment, mitigation or prevention of a disease, disorder, abnormal physical state, os symptoms thereof. Also used in restoring, correcting or modifying organic functions, and for disinfection in premises in which food is manufactured, prepared, or kept.
Pharmaceutics
Area of study concerned with formulation, manufacture, stability and effectiveness of dosage forms.
Pharmacology
Science of the properties of drugs and their effects on the body
Pharmacokinetics
Study of the kinetics of absorption, distribution, metabolism, and excretion of drugs and their corresponding pharmacologic response in animals/humans
Clinic
A facility or area where ambulatory pt are seen for special study and treatment
Excipients
Non-medical compounds combined with a drug to make it suitable for delivery, with no pharmacological effect
Objective of dosage form design
Predictable therapeutic response which is capable of large scale manufacture with reproducible product quality
Examples of excipients
Citric acid & NaCO3 (pH), phenol (preservative), sterilized water & alc (solvent), peppermint oil & menthol (flavour)
What are the 2 classes of drug delivery?
Enteral (GI tract)
Parenteral (anything but)
Bioavailability
Extent of absorption and rate at which an administered dose reaches systemic circulation in its active form
Hepatic First Pass Effect
HFPE = drug passes through liver and is already metabolized before it can properly circulate through the bloodstream
Factors of ADME
Rate of ABSORPTION
DISTRIBUTION extent
METABOLISM
ELIMINATION
What is the volumetric capacity of the esophagus?
1.5L
T/F: Drugs can be partially absorbed through the esophagus
F: no absorption of drug, but it can still encounter trouble here (get stuck)
Describe the grapefruit effect
Many drugs cannot be eaten alongside grapefruit because they share a lot of the same enzymes with the fruit. The liver may target either one as a result, interfering with the drug’s ability to dissolve into your bloodstream.
Natural triglycerides inhibit gastric ________
Motility: changes how the stomach churns and empties
Why does the Cp vs. t curve for oral administration profile slow and reach a peak in the absorption phase?
There is still elimination causing a maximum at a specific t
List 2 advantages and 2 disadvantages of oral administration
A: pt compliance, cheap compared to other routes, transit time consistent
D: HFPE, effect too slow for emergencies, presence of food retards abs
List 2 advantages and 2 disadvantages of rectal administration
A: useful alternative for pt, avoids some HFPE
D: Lack of pt compliance, abs can be unpredictable
List 2 advantages and 2 disadvantages of buccal and/or sublingual administration
A: No HFPE (cells are appropriately vascularized), rapid abs
D: Inconvenient, limited to small doses, bad tastes
List 2 advantages and 2 disadvantages of iv administration
A: 100% bioavail, precise and accurate, rapid onset
D: Pt compliance low, greater risk of OD, $$$
Describe the infusion Cp vs. t curve
Just a straight horizontal line (rate is controlled, Css)
T/F: Intra-arterial are a more common and preferred method of injection than iv.
F: harder and more complicated, require more pressure, but more effective than iv injections. Used for blood clots and in cases of emergencies
Why is the muscle more acidic than most tissue?
Higher mitochondria = higher metabolism = more acidic products being released, especially during exercise. Causes muscle tissues to become more acidic
T/F: im and sc administration have bioavail = 100%
F: < 100%
Surface area of skin on the “average” standing human?
1.8 m2
Describe the transdermal patch administration Cp vs. t profile
- Slight lag time after 0 and before curve moves upwards
- Amount of drug absorbed goes up, then plateaus for a while until returns back down
List 2 limits of transdermal patches
Drug must be potent, effective when delivered slowly
What makes a drug qualified to be administered using a transdermal patch?
- Low MEC
- Subject to extensive HFPE if given orally
- Taken many times/day if given orally
- Unpleasant side-effects to GI tract if given orally
- Small (low MW)
List 2 advantages and 2 disadvantages of nasal administration
A: avoids HFPE, convenient, good bioavail (70-80%)
D: Variable cond’ts of nose, complex formulation due to buffering of nose
What are some of the biggest challenges with pulmonary drugs?
Lungs are very reactive and full of immune cells. When fibrosis occurs, scar tissue begins to form.
List 2 advantages and 2 disadvantages of pulmonary administration
A: convenient, avoids HFPE, rapid onset
D: Only small bit of drug reaches alveoli, pt compliance, variable in dose
