ATI RN
Chapter 11 principles of pharmacology Questions
Question 1 of 5
Which technique is typically used to mill camphor?
Correct Answer: C
Rationale: Pulverization by intervention (C) is typically used to mill camphor, adding a volatile solvent (e.g., alcohol) to reduce it to a fine powder, then evaporating the solvent, overcoming camphor's waxy nature. Trituration (A) grinds without solvent, less effective here. Levigation (B) uses a liquid to make a paste, not ideal for camphor. Geometric dilution (D) mixes powders, not mills. Attrition (original E) is mechanical grinding, less specific. This method ensures uniformity for incorporation into ointments or inhalants, leveraging camphor's volatility for pharmaceutical use.
Question 2 of 5
The passage of drug molecules from a region of high drug concentration to a region of low drug concentration is known as
Correct Answer: D
Rationale: Simple diffusion (D) is the passage of drug molecules from high to low concentration, a passive process driven by the gradient (e.g., ethanol across membranes), requiring no energy. Active transport (A) uses energy against the gradient. Bioavailability (B) is the fraction reaching systemic circulation. Biopharmaceutics (C) studies formulation effects. Pinocytosis (original E) involves vesicular uptake. Diffusion's lipid solubility dependence governs most drug absorption, a fundamental principle in pharmacokinetics, impacting onset and distribution rates.
Question 3 of 5
Drug that show nonlinear pharmacokinetics have which property?
Correct Answer: B
Rationale: Nonlinear pharmacokinetics feature an elimination half-life (t_½) that increases as the dose increases (B), as elimination (e.g., via saturable enzymes) becomes zero-order (e.g., phenytoin), prolonging clearance at high doses. Option A is false; metabolite ratios change with saturation. Option C is incorrect; AUC rises disproportionately. Option D is wrong; high doses shift from first-order. Option E (original) about steady-state is first-order-specific. This saturation alters dosing (e.g., phenytoin monitoring), critical to avoid toxicity in nonlinear drugs.
Question 4 of 5
The principle of superposition in designing multiple-dose regimens assumes that
Correct Answer: D
Rationale: The principle of superposition assumes early doses do not affect subsequent doses (D), valid in first-order kinetics where each dose's elimination is independent, summing linearly to predict steady-state (e.g., amoxicillin). Option A suggests nonlinearity (e.g., phenytoin). Option B is zero-order (e.g., ethanol). Option C overestimates; steady-state is ~4-5 half-lives. Option E (original) is unrelated. This linearity simplifies multiple-dose design, ensuring predictable accumulation, critical for maintaining therapeutic levels without toxicity.
Question 5 of 5
Which of the following terms best describes a co-factor that is firmly bound to an apoenzyme?
Correct Answer: B
Rationale: A prosthetic group (B) is a cofactor firmly bound to an apoenzyme (e.g., heme in hemoglobin), forming a functional holoenzyme, unlike loosely bound coenzymes (C, e.g., NADâº). Holoenzyme (A) is the complete enzyme. Transferase (D) is an enzyme class. Heteropolysaccharide (original E) is unrelated. This tight binding enhances enzyme stability and activity, critical in drug metabolism (e.g., CYP450 with heme), influencing pharmacokinetics and therapeutic outcomes.