WorksheetsIntro to Biopharm and Pharma. Models
Total questions: 50
Worksheet time: 25mins
Biopharmaceutics is best described as the study of:
Receptor binding and post-receptor effects
Factors influencing bioavailability and using them to optimize therapeutic activity of drug products
Kidney excretion via only tubular reabsorption
Drug’s irreversible removal via any mechanism
Which list matches the specified interrelationship studied in biopharmaceutics?
Physicochemical properties, dosage form, route, rate/extent of absorption
Receptor binding, intensity, time course
Glomerular filtration, tubular secretion, tubular reabsorption, bile excretion
Elimination + distribution = elimination
Which of the following is NOT a physical-chemical property?
Particle size
Specific surface area
Hydrophobicity
Polymorphism
Receptor density
Consistent bioavailability is especially important when a drug:
Has a wide therapeutic range
Has a narrow therapeutic range
Is only given IV
Is eliminated only via lungs
Pharmacokinetics is described as:
What the drug does to the body
What the body does to the drug; kinetics of ADME
Only distribution and metabolism
Only receptor binding and post-receptor effects
Which statement matches the definitions given?
Elimination = Distribution + Excretion
Disposition = Metabolism + Excretion
Disposition = Distribution + Elimination
Disposition = Receptor binding + post-receptor effects
Clinical pharmacokinetics involves individually optimized dosing strategies based on:
Only patient age and weight
Patient’s disease state and patient-specific considerations
Only first-pass effect
Only urine monitoring
Pharmacodynamics is:
What the body does to the drug
What a drug does to the body
Irreversible drug removal via kidneys
Dose validation in animals only
Onset of action is the time when:
Plasma concentration falls below MEC
The drug reaches therapeutic range
Cmax is achieved
Elimination ends
In a plasma level vs time curve, MTC and MEC stand for:
Maximum therapeutic concentration; minimum effective concentration
Minimum toxic concentration; minimum effective concentration
Mean tissue concentration; maximum elimination constant
Minimum tissue concentration; minimum elimination concentration
A limitation of tissue biopsy drug concentration is that it:
Cannot indicate presence of drug
Always reflects concentration in all tissues
May not reflect drug concentration in other tissue or all parts of the source material
Is the most direct approach in PK
Drug concentrations in urine are described as an indirect method to ascertain bioavailability because:
Rate/extent excreted indicate rate/extent of absorption
Rate/extent excreted indicate receptor binding
Rate/extent excreted indicate partition coefficient
Rate/extent excreted indicate manufacturing process
Which feature is specifically associated with intravascular administration?
Presence of absorption phase
Absence of absorption phase
Incomplete absorption is expected
Onset/duration strongly influenced by formulation and dosage form type
Which statement is specifically made about intravascular administration?
Used mostly for mild/self-limited disease states
Adverse reactions are difficult to reverse/control; dose calculation/administration accuracy is critical
Entire dose may not reach circulation due to first-pass metabolism
Requires an absorption phase to occur
Which route is NOT extravascular?
Oral
Rectal
Intramuscular
Intra-arterial
For extravascular administration, onset and duration are influenced by:
Only renal clearance mechanisms
Formulation/type of dosage form, route, physico-chemical properties, and other physiological variables
Only receptor binding kinetics
Only tissue biopsy sampling
A limitation of extravascular administration is:
Entire dose may not always reach general circulation
No absorption phase occurs
Entire dose always reaches general circulation
Adverse reactions are always reversible
Absorption is defined as the process by which a drug proceeds from the site of administration to:
The receptor site only
The site of measurement
The liver only
The nephron only
Which is included as a physiological barrier to absorption?
GI tract
Bone marrow
Retina
Synovial fluid
For an extravascular route, maximum concentration (Cmax) is reached when:
Rate of elimination exceeds rate of absorption
Rate of absorption equals rate of drug elimination
Drug first appears in plasma
Drug falls below MEC
Distribution is defined as:
Irreversible removal via kidneys
Reversible transfer to/from site of measurement
Only partitioning into fat
Only movement from liver to bile
Which organ is identified as the principal organ of drug metabolism?
Brain
Kidneys
Liver
Skin
Drug removal via mother’s milk:
Is the primary excretion route for mothers
Is not significant for the mother, but can affect the infant if consumed in sufficient quantity
Prevents infant exposure due to metabolism in milk
Only applies to IV drugs
Elimination is:
Absorption + distribution
Metabolism + excretion
Distribution + absorption
Biopharmaceutics + pharmacodynamics
“First-pass effect” is also known as:
Bioequivalence
Presystemic metabolism
Disposition
Distribution
It is challenging to measure drug concentration in a tissue following intravenous
administration.
False
True
A drug molecule in urine can reenter the blood by a process known as tubular reabsorption.
True
False
“Time for peak plasma level” is the time of maximum drug concentration and indicates the average rate of absorption.
True
False
Intravascular administration has an absorption phase, so onset depends heavily on dissolution rate.
True
False
A pharmacokinetic model is best defined as:
A physical organ system that determines drug distribution
A hypothesis expressed mathematically to describe a quantitative relationship
A lab assay used to measure plasma concentrations
A constant that cannot be estimated experimentally
Which pairing is correct?
Variable = constant for the drug; Parameter = experimental data
Variable = experimental data; Parameter = constant estimated from data
Variable = dependent only; Parameter = independent only
Variable = assumption; Parameter = hypothesis
In a typical plasma concentration–time profile, which is dependent?
Time
Dose
Plasma concentration
Route of administration
Which statement is a limitation of PK models?
Plasma drug concentration always predicts drug action
A model never requires assumptions
Genetic differences and disease state can modify drug response
A model always fits every observation
A compartment in compartmental PK is:
A real anatomical organ
A real fluid space
Not a real anatomical area; a conceptual grouping of tissues with similar blood flow/affinity
Always a closed system
A drug is most consistent with a one-compartment open model when:
Distribution equilibrium is reached at a finite time
Rapid distribution equilibrium occurs essentially immediately; distribution vs elimination phases cannot be distinguished
Elimination occurs only from the peripheral compartment
There is always a biphasic decline on a semilog plot
In the two-compartment model described, which would most likely be considered peripheral compartment?
Blood and kidney
Liver and kidney
Cartilage and fatty tissue
Blood and liver
Which drug property is most likely to indicate determining whether a higher-compartment model is needed?
Degree of plasma protein binding
Distribution speed/property
First-pass metabolism
Renal clearance only
Why is selecting the right compartment model and equation critical?
Because AUC becomes independent of dose
Wrong choices produce erroneous PK parameters and predictions
Because distribution always occurs after elimination
Because models eliminate the need for early sampling
Before selecting a compartment model, you must have:
Urine metabolite profiles only
Plasma concentration vs time data
Only tissue biopsy concentrations
Only an assumed half-life
Which approach aligns with the recommended strategy?
Start with 3 compartments to avoid underfitting
Start with 1 compartment; if fit is inadequate, move to 2+ compartments
Choose a model solely based on the route of administration
Choose a model without statistical analysis
Why is collecting plasma samples early after IV administration emphasized?
To increase Ka
To ensure Cp0 is estimated accurately
To avoid distribution equilibrium
To eliminate the need for statistical analysis
A model is a hypothesis using mathematical terms to describe a discrete quantitative relationship.
True
False
According to the one-compartment model, drug concentrations will be in equilibrium throughout the body shortly after an ________ dose
Intraperitoneal
Intravenous bolus
Oral solid
Oral liquid
The unique characteristic of a one-compartment model is that drug distribution equilibrium is attained very rapidly following the administration of a dose; this simply suggests that the amount and/or the concentration of drug, at a time, will be identical in all tissues and organs.
True
False
Regarding a two-compartment model for intravenous bolus injection, a drug is always monitored in the blood, plasma or serum.
True
False
According to mass balance consideration, an intravascular dose is equal to a sum of which of the following items? (Select all that apply).
Amount at the absorption site
Amount distributed in vascular tissues
Amount in the body
Amount metabolized
Amount excreted
In a Cp vs time plot, which is the dependent variable?
Time
Dose
Plasma drug concentration
Route of administration
In a 2-compartment IV bolus model:
α and β are micro rate constants
α and β are hybrid rate constants
α = elimination constant; β = distribution constant
α = absorption constant; β = excretion constant
Distribution equilibrium in a two compartment model is achieved when:
Xc=Xp
K10=0
XcK12=XpK21
A=B
