Pharmaceutics Quiz 9

Below are some statements above BSC III drugs i. Intestinal membrane absorption is the rate-limiting step in the absorption of class III drugs ii. Class III drugs are better absorbed in the upper part of the small intenstine iii. any meal co-administerd with class III drugs decreases their absorption proportionally to its fat content iv. any meal co-administerd with class III drugs decreases their absorption which is not related to its fat content a. only 1, 2 and 4 are correct b. All are correct c. Only 3 is correct d. None

A

Calculate the solubility of ibuprofen, a weakly acidic drug (pKa=5.2 and intrinsic solubility= 2 mg/mL) in a medium mimicking intestinal fluid which pH is 8. a. 1262 mg/mL b. 10.4 mg/mL c. 41.6 mg/mL d. 18.4 mg/mL

A

Chemicals with high Ko/w values (e.g. greater than 10^4) are very hydrophobic a. True b. False

A

Digoxin is a poorly soluble drug. Therefore its physical forms such as particle size would have a significant influence on its therapeutic effects (T/F)? a. True b. False

A

Generally branched chain is more soluble then straight chain of an isomer (T/F)? a. True b. False

A

Generally, the greater the value of the partition coefficient the higher the lipid solubility of the solute a. True b. False

A

Solubility among isomers increase with i. decreasing boiling and melting point for liquid and solid respectively ii. increasing boiling and melting point for liquid and solid respectively a. Only 1 is correct b. Only 2 is correct c. All are correct d. None are correct

A

The concept of partition coefficient is involved in the following pharmaceutical sciences i. preservation of water-oil systems ii. drug action in non-specific sites iii. absorption and distribution of drugs throughout the body a. All are correct b. Only 1 is correct c. Only 3 is correct d. None of the above

A

The most commonly used method to measure the lipophilicity is by determining the partition coefficient via the shake-flask method a. True b. False

A

The temperature can exert a greater influence on the solubility of a drug if it is a weak acid or base a. True b. False

A

We have a 1:1 mixture of a polar and a non-polar solvent. If we add a non-polar drug to this mixture, where would you find most of the drug? a. Non-polar solvent b. Polar Solvent c. Interface of the mixture d. Surface of the mixture

A

What is the minimum time required for an IV injection of a 22mg dose of a poorly water soluble drug to ensure that precipitastion does not occur. Given that, the solubility in drug plasma= 0.7mg/mL and venous flow rate= 50mL/min? a. 38 seconds b. 35 seconds c. 60 seconds d. 50 seconds

A

Below are some statements about BSC class 1 drugs: i. Class I drugs are well absorbed and are affected by a limited set of interactions that alter the drugs absorption ii. Interactions that delay gastric emptying will delay absorption of these drugs iii. Gastric emptying rate has a significant effect on absorption of class 1 drugs iv. Gastric emptying rate does NOT affect absorption of class 1 drugs a. Only 1 is correct b. Only 1-3 are correct c. All of the above d. None of the above

B

Minocycline and Doxycycline have a greater log P value than that of other tetracyclins. Which of the following statements are correct about them? i. only minocycline and doxycycline pass through the blood brain and blood ocular barrier while other tetracyyclines do not ii. Minocycline/doxycylcine only pass through the blood brain barrier but not through the blood ocular barrier iii. Minocycline/doxycycline pass through the blood ocular barrier but not through the blood brain barrier a. Only 1 and 2 are correct b. Only 1 is correct c. All are correct d. None

B

Phenobarbital is a weakly acidic. What would be its solubility in solvents A (pH 7), B (pH 8) and C (pH 10)? a. it would not dissolve in any of the solvents because they all have pH in the basic range b. It would dissolve in C most c. It would dissolve in B most d. It would dissolve in A most

B

Knowledge and understanding of the equilibrium solubility of a drug is absolutely essential because it plays a critical role in: i. The drug discovery process ii. Drug formulation process iii. Selection of dosage form iv. Drug dissolution in the GI tract v. Drug absorption a. Only 1 is correct b. Only 1 and 2 are correct c. All are correct d. None of the above

C

The statement: "In general, the higher the temperature the greater the solubility of a drug" only applies to those solids which posses: a. negative heat of solution b. heat of solution = 0 c. a postivie heat of solution

C

Which one of the following are not affected by partition coefficient a. The solubility and permeability of a drug b. the relationship between molecular structure and biological activity of a drug c. The passage of water through the biomembrane

C

The concept of partition coefficient applies only to a. polar solvents b. non-polar solvents c. Concentrated solutions d. Dilute solutions

D

When atropine was added to a mixture of water (Solvent 1) and octanol (Solvent 2) at 25 deg C its concentration in octanol (C1) and water (C2) was 3.96 mg/mL and 2.2 mg/mL respectively. What is the partition coefficient (P) in this system? a. 0.55 octanol/water b. 8.71 octanol/water c. 8.18 octanol/water d. 1.8 octanol/water

D