week 3: dissolution

for a drug with poor solubility but high permeability, which parameter is the rate-limiting step for oral absorption?

a) hepatic metabolism

b) membrane permeability

c) dissolution rate

d) gastric emptying rate

c

which form of a drug generally demonstrates greater solubility, thereby enhancing dissolution rate, but may suffer from reduced stability?

a) crystalline form

b) amorphous form

c) complexed salt form

d) hydrated form

b

which physiological factor most directly influences the rate of drug dissolution and absorption in the gastrointestinal tract?

a) renal clearance

b) plasma protein binding

c) gastric emptying rate

d) hepatic enzyme activity

c

tetracycline analogues exhibit reduced absorption when co-administered with milk due to:

a) formation of insoluble complexes with calcium

b) salt formation that enhances solubility

c) enhanced crystalline stability in acidic pH

d) increased gastric empyting rate

a

according to the Noyes-Whitney equation, which of the following changes would most directly increase the dissolution rate of a poorly soluble drug?

a) increasing particle size of the drug

b) increasing surface area (S) through micronization

c) decreasing saturation solubility (Cs)

d) decreasing the dissolution rate constant (k)

b

which of the following statements is correct regarding the hydration state of drug molecules?

a) solubility is unaffected by hydration state

b) hydrated forms are always more soluble than anhydrous forms

c) both hydrated and anhydrous forms dissolve at the same rate

d) anhydrous forms are generally more soluble than hydrated forms

d

which of the following dosage forms bypasses the dissolution step, leading to faster absorption?

a) solution

b) tablet

c) capsule

d) suspension

a

in the context of dissolution and drug absorption, an ideal drug candidate should possess:

a) large particle size and crystalline stability

b) poor aq solubility but high permeability

c) high aq solubility and good membrane permeability

d) high protein binding and low hepatic metabolism

c

which strategy is most effective in enhancing dissolution rate of a poorly soluble crystalline drug without altering its chemical form?

a) converting to a hydrated form

b) reducing particle size

c) forming less soluble complexes

d) enhancing protein binding

b

the dissolution rate of sodium and potassium salts of weak organic acids compared to their parent free acid is typically:

a) faster, due to enhanced aq solubility

b) much slower due to ion pairing

c) dependent only on gastric pH, not on salt form

d) similar, as salt forms do not influence dissolution

a