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Indicate which of the following factors can increase or decrease column efficiency in liquid chromatography. Give reasons in each case.

  1. Very low flow rate
  2. Large stationary phase particle size
  3. Small stationary phase particle size
  4. Regularly shaped stationary phase
  5. Irregularly shaped stationary phase
  6. High temperature
  7. Low temperature
  8. Non‐uniform stationary phase particle size
  9. High diffusion coefficient in mobile phase
  10. Low diffusion coefficient in mobile phase
  11. Longer column
  12. Large dead volume


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Related questions

Multiple Choice questions 2 points each

1. Creatinine clearance is a commonly used estimate of:

A)Glomerular filtration rate (mL/min)

B)Tubular secretion (mL/min)

C)Total renal blood flow (mL/min)

D)Renal reabsorption (cc/min)

E)Steady state muscle breakdown rate (mcg/min)

2. Which of the following is not a measure of exposure?

a) Peak concentration

b) Time of maximum concentration

c) Area under the concentration time curve

d) Concentration measured 2 hours after dose administration

3. A clinically impactful drug interaction based upon inhibition of cytochrome P450 is most likely when:

a)The drug is metabolized by multiple enzymes

b)The drug has a narrow therapeutic index

c)There is limited variation in interindividual enzyme activity in the involved enzyme

d)The drug is a substrate of P-glycoprotein

e)All of the above

2. Why are dose-response (or concentration-response) analyses recommended for drug approval by a regulatory agency?

a) To increase the potential for adverse reactions in clinical trials in order to fully characterize the safety profile

b) To prolong the length of time it takes for drug approval

c) To maximize the likelihood that optimal drug dose will be prescribed after approval

d) To reduce the costs of clinical trials

e) To explore all possible disease state indications at time of initial approval

5. Which of the following is true of inhaled delivery of an aerosolized drug suspension?

a)An ideal drug would have low first pass hepatic metabolism to maximize systemic absorption

b)In contrast to milled powders, drugs in suspension are dosed in partial pressures

c)Efficiency of drug delivery by multi-dose inhalers is highly dependent upon patient technique

d)Typical multi-dose inhalers produce a very homogenous particle size of drug

e)Nebulized delivery of drug by face mask is not appropriate for children, demented or obtunded patients

6. The apparent volume of distribution (Vd):

a)Does not represent an actual physiologic volume

b)Can never be higher than total body water volume

c)Can be determined using only the half life of a drug

d)Will be large in a drug that is highly bound to serum proteins

e)Is usually small in drugs that require a loading dose

7. Which of the following characteristics of a drug make it most amenable to removal by hemodialysis?

a)Large volume of distribution

b)Large molecular weight

c)Strong protein binding

d)Good water solubility

8. Which is the best predictor of need for dosage adjustment in hepatic disease?

Child Pugh score

Portal splanchnic pressure (as measured by peripheral heart rate)

Degree of fibrosis and shunt on ultrasound

Levels of liver function tests

There is no single marker of hepatic dysfunction

9. Fexofenadine is not metabolized but is a P-glycoprotein (Pgp) substrate. How does St. John’s Wort cause decreased serum fexofenadine levels?

Inhibition of gut Pgp

Induction of gut PgP

Induction of CNS Pgp

Inhibition of biliary Pgp

None of the above

10. Which of the following is the best measure of renal function?

a)age

b)random urine creatinine concentration

c)spot plasma creatinine concentration

d)estimated creatinine clearance (Cockroft Gault)

e)Child-Pugh

11. Which pharmacokinetic parameter is the best measure of total systematic drug exposure after an oral dose?

a)Cmax

b)Elimination half life

c)Absorption rate constant

d)Area under the curve

e)Clearance

12. Which of the following is a mechanism that would cause a drug to have zero order elimination in humans?

a)Ultra-metabolizer genotype

b)Enterohepatic recirculation

c)High serum protein binding

d)Saturation of the prime metabolic enzyme

e)Sustained release version of a drug

13. Phase II metabolic metabolism:

a)Involves the covalent binding of a polar side chain

B)Always follows phase 1 metabolism

c)Employs breaking of aromatic ring structures

d)Is not subject to pharmacogenetic variation

e)Occurs exclusively pre-systemically, in the gut lumen

14. Which is not a high profile FDA Initiative?

a)Orphan Disease Act

b)Childhood Vaccine Act

c)Rare Disease Act

d)Breakthrough Drug Designation

15 In explaining risk posed by pharmaceutical R&D, which is not a development risk:

a)Patient population

b)Clinical endpoint

c)Predictability of trials

d)Competitive advantage

16. The key pivotal trials undertaken as part of the IND are part of which phase of the clinical drug development process?

a)Phase I

b)Phase II

c)Phase III

d)Phase IV

17. Which is not an EU Regulatory Process

a)Centralized Procedure

b)Certificate of Pharmaceutical Product Procedure

c)De-Centralized Procedure

d)Mutual Recognition

18. The role of experimental medicine strategies is to

a)Explore disease and drug biology to support go/no go decisions

b)Generate and fully validate biomarkers for FDA approval

c)Primarily to co-develop diagnostic tests to be filed with the NDA (new drug application)

d)Harmonize FDA and EMA phase 1 requirements

e)Define the pharmacokinetics of exploratory drugs in healthy volunteers or selected patient populations

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