PHA 317 Final UPDATED ACTUAL
Questions and CORRECT Answers
What is the pH of a buffer containing 0.1 -M acetic acid (pKa 4.8) and 0.08 M sodium acetate? -
CORRECT ANSWER - 4.7
What percentage of an acidic drug indomethacine (pKa 4.5) exist in the original unionized form
in an intestinal tract buffered at pH 8.0? - CORRECT ANSWER - 0.03%
What molar ratio of sodium acetate and acetic acid (pKa 4.76) should you use to prepare an
acetate buffer of pH 5? - CORRECT ANSWER - 1.74:1
Stronger bases, such as guanethidine (pKa > 11) are ionized throughout the GI tract and tend to
be well-absorbed throughtout the GI tract. - CORRECT ANSWER - false
The biological membrane is covered on both side by lipid layers which are interrupted by water
filled pores. Which of the following statements is correct? - CORRECT ANSWER - The
radius of the aqueous pores on biomembrane is approximately 4 Angstrom, therefore, any
hydrophilic drug smaller than 4 Angstrom can get transported through it easily.
Strong bases, which are those with pKa values between 5 and 11, show pH-dependent
absorption. - CORRECT ANSWER - true
Digestion and absorption of foodstuff occur separately at different times in the small intestine -
CORRECT ANSWER - false
The greater the pKa value, the stronger the acid would be. - CORRECT ANSWER - false
Below are some statements about the concept of equilibrium in pharmaceutics:
i. a condition at which all acting influences are canceled by others, resulting in a stable, balanced,
or unchanged system
,ii. the state of a chemical reaction in which its forward and reverse reactions occur at equal rates
so that the concentration of the reactants and products remain unchanged with time
iii. a condition at which no change in concentrations of either reactant or product is observed
because they stop reacting with each other
iv. the state of a reversible chemical reaction in which the forward and reverse reactions occur at
equal rates so that there are no further changes in the concentrations of the reactants and products
- CORRECT ANSWER - only i, ii, and iv are correct
The transport of weak acidic drugs across gastrointestinal membrane is influenced by pH only if
their pKa values are within the range of 3-7 - CORRECT ANSWER - true
Stronger bases, such as guanethidine (pKa > 11) are ionized throughout the GI tract and tend to
be poorly absorbed - CORRECT ANSWER - true
The lower the pKa value for an acid, the greater hydronium ion concentration it would produce
on being added to water - CORRECT ANSWER - true
Generally, absorption or transport of a drug in ionized form through GI membrane would be
more than its unionized form - CORRECT ANSWER - false
The polar surface area is defined as the sum of the Van der Waals surface areas for the polar
ataoms, oxygens, nitrogens, and attached hydrogen atom (or the number of H-bonded donors and
H-bond acceptors) - CORRECT ANSWER - true
How are lipids arranged on both side of a biomembrane? - CORRECT ANSWER -
perpendicularly
The pH range of duodenum is: - CORRECT ANSWER - 5 to 7
The brush border consists of a 3 mm thick uniform coating of mucopolysaccharide which is
found lining the internal wall of stomach only - CORRECT ANSWER - false
, Equilibrium is involved in the following processes playing an important role in pharmaceutics:
i. ionization of weak acidic or basic drugs
ii. partition coefficient and lipid solubility of a drug
iii. saturation solubility
iv. diffusion and dissolution of drug - CORRECT ANSWER - all i-iv are correct
Below are some statements about the polar surface area:
i. the greater the polar surface area of a drug, the greater would be its oral absorption as well as
penetration through brain
ii. the smaller the polar surface area of a drug, the greater would be its oral absorption as well as
penetration through brain - CORRECT ANSWER - only ii is correct
Which statement is correct?
i. ionized drugs are useful for optimum therapeutic effect
ii. unionized drugs are useful for optimum therapeutic effect
iii. either ionized or unionized drugs could be useful for optimum therapeutic effect depending
on site of pharmacological action - CORRECT ANSWER - only iii is correct
If the rate of injection of a drug and its solubility are 5mg/min and 0.6mg/mL, respectively, what
blood or saline flow rate is required to prevent precipitation of the drug? - CORRECT
ANSWER - greater than 8.33mL/min
What is the minimum time required for the IV injection of a 22 mg dose of a poorly water
soluble drug to ensure that precipitation dose not occur? Given that solubility of the drug in
plasma = 0.7 mg/mL and venous flow rate = 0 mL/min - CORRECT ANSWER - 38
seconds
What is the pH below which sulfadiazine (pKa = 6.48) will begin to precipitate in an infusion
fluid, when the initial molar concentration of sulfadiazine sodium is 4x10^-2 mole/L and the
solubility of sulfdiazine is 3.07x10^-4 mole/L - CORRECT ANSWER - 8.60
Questions and CORRECT Answers
What is the pH of a buffer containing 0.1 -M acetic acid (pKa 4.8) and 0.08 M sodium acetate? -
CORRECT ANSWER - 4.7
What percentage of an acidic drug indomethacine (pKa 4.5) exist in the original unionized form
in an intestinal tract buffered at pH 8.0? - CORRECT ANSWER - 0.03%
What molar ratio of sodium acetate and acetic acid (pKa 4.76) should you use to prepare an
acetate buffer of pH 5? - CORRECT ANSWER - 1.74:1
Stronger bases, such as guanethidine (pKa > 11) are ionized throughout the GI tract and tend to
be well-absorbed throughtout the GI tract. - CORRECT ANSWER - false
The biological membrane is covered on both side by lipid layers which are interrupted by water
filled pores. Which of the following statements is correct? - CORRECT ANSWER - The
radius of the aqueous pores on biomembrane is approximately 4 Angstrom, therefore, any
hydrophilic drug smaller than 4 Angstrom can get transported through it easily.
Strong bases, which are those with pKa values between 5 and 11, show pH-dependent
absorption. - CORRECT ANSWER - true
Digestion and absorption of foodstuff occur separately at different times in the small intestine -
CORRECT ANSWER - false
The greater the pKa value, the stronger the acid would be. - CORRECT ANSWER - false
Below are some statements about the concept of equilibrium in pharmaceutics:
i. a condition at which all acting influences are canceled by others, resulting in a stable, balanced,
or unchanged system
,ii. the state of a chemical reaction in which its forward and reverse reactions occur at equal rates
so that the concentration of the reactants and products remain unchanged with time
iii. a condition at which no change in concentrations of either reactant or product is observed
because they stop reacting with each other
iv. the state of a reversible chemical reaction in which the forward and reverse reactions occur at
equal rates so that there are no further changes in the concentrations of the reactants and products
- CORRECT ANSWER - only i, ii, and iv are correct
The transport of weak acidic drugs across gastrointestinal membrane is influenced by pH only if
their pKa values are within the range of 3-7 - CORRECT ANSWER - true
Stronger bases, such as guanethidine (pKa > 11) are ionized throughout the GI tract and tend to
be poorly absorbed - CORRECT ANSWER - true
The lower the pKa value for an acid, the greater hydronium ion concentration it would produce
on being added to water - CORRECT ANSWER - true
Generally, absorption or transport of a drug in ionized form through GI membrane would be
more than its unionized form - CORRECT ANSWER - false
The polar surface area is defined as the sum of the Van der Waals surface areas for the polar
ataoms, oxygens, nitrogens, and attached hydrogen atom (or the number of H-bonded donors and
H-bond acceptors) - CORRECT ANSWER - true
How are lipids arranged on both side of a biomembrane? - CORRECT ANSWER -
perpendicularly
The pH range of duodenum is: - CORRECT ANSWER - 5 to 7
The brush border consists of a 3 mm thick uniform coating of mucopolysaccharide which is
found lining the internal wall of stomach only - CORRECT ANSWER - false
, Equilibrium is involved in the following processes playing an important role in pharmaceutics:
i. ionization of weak acidic or basic drugs
ii. partition coefficient and lipid solubility of a drug
iii. saturation solubility
iv. diffusion and dissolution of drug - CORRECT ANSWER - all i-iv are correct
Below are some statements about the polar surface area:
i. the greater the polar surface area of a drug, the greater would be its oral absorption as well as
penetration through brain
ii. the smaller the polar surface area of a drug, the greater would be its oral absorption as well as
penetration through brain - CORRECT ANSWER - only ii is correct
Which statement is correct?
i. ionized drugs are useful for optimum therapeutic effect
ii. unionized drugs are useful for optimum therapeutic effect
iii. either ionized or unionized drugs could be useful for optimum therapeutic effect depending
on site of pharmacological action - CORRECT ANSWER - only iii is correct
If the rate of injection of a drug and its solubility are 5mg/min and 0.6mg/mL, respectively, what
blood or saline flow rate is required to prevent precipitation of the drug? - CORRECT
ANSWER - greater than 8.33mL/min
What is the minimum time required for the IV injection of a 22 mg dose of a poorly water
soluble drug to ensure that precipitation dose not occur? Given that solubility of the drug in
plasma = 0.7 mg/mL and venous flow rate = 0 mL/min - CORRECT ANSWER - 38
seconds
What is the pH below which sulfadiazine (pKa = 6.48) will begin to precipitate in an infusion
fluid, when the initial molar concentration of sulfadiazine sodium is 4x10^-2 mole/L and the
solubility of sulfdiazine is 3.07x10^-4 mole/L - CORRECT ANSWER - 8.60
