Goodman and Gilman's The
Pharmacological Basis of Therapeutics
14th Edition
Author(s)Laurence Brunton; Bjorn Knollmann
Print ISBN: 9781264258079
,Question 1
A researcher isolates a biologically active compound from a medicinal
plant and determines that it produces a reproducible pharmacological
effect. Which step best represents the transition from observing the
plant's activity to identifying a potential drug lead?
A. Increasing the dose until toxicity occurs
B. Isolating and characterizing the active chemical constituent
,C. Administering the crude plant extract to a larger population
D. Eliminating all compounds that lack oral bioavailability
Correct Answer:
B. Isolating and characterizing the active chemical constituent
Rationale:
B is correct because isolating and characterizing the active constituent
identifies the chemical entity responsible for the observed biological
activity and provides a defined starting point for further drug
development. This approach converts a complex natural mixture into a
tractable molecular lead.
A is incorrect because determining toxicity is important later but does
not identify the active constituent.
C is incorrect because increasing clinical exposure to an undefined
extract does not establish which molecule produces the effect.
D is incorrect because oral bioavailability is an important development
property, but compounds can be valuable leads even when their initial
pharmacokinetic properties are suboptimal.
Question 2
What is the primary purpose of a screening program during early drug
discovery?
A. To guarantee that a compound will be safe in humans
B. To identify compounds that produce a desired biological effect
C. To determine the final manufacturing cost of a drug
D. To establish the optimal clinical dose
, Correct Answer:
B. To identify compounds that produce a desired biological effect
Rationale:
B is correct because screening is used to identify molecules with
measurable biological activity that may serve as leads for further
optimization. Screening can be directed toward a molecular target or a
desired phenotype.
A is incorrect because screening does not establish human safety.
Safety requires additional preclinical and clinical evaluation.
C is incorrect because manufacturing economics are evaluated
separately from the initial identification of biological activity.
D is incorrect because the optimal clinical dose is established much
later through pharmacokinetic, pharmacodynamic, safety, and clinical
studies.
Question 3
A medicinal chemist modifies a promising lead compound by replacing
one chemical group with another while retaining activity at the
intended target. What is the main objective of this process?
A. To optimize properties such as potency, selectivity, and
pharmacokinetics
B. To eliminate the need for biological testing
C. To convert every lead into a naturally occurring compound
D. To ensure that the compound has no adverse effects