1. In the case of hydrophobic drugs, micronization results in a decrease in effective surface area and thus fall is dissolution rate. Which of the below sentences cannot be a reason for the given statement?
a) The hydrophobic surface of the drugs adsorbs onto their surface which inhibits their wettability
b) The particles reaggregate to form larger particles due to their high surface free energy
c) Extreme reduction in the particle size imparts surface charges that may prevent wetting
d) Extreme reduction in the size brings the hydrophobic amino acids to the surface
Explanation: In the case of hydrophobic drugs, micronization results in a decrease in effective surface area and thus fall is dissolution rate. Three reasons are, Hydrophobic surface of the drugs adsorbs onto their surface which inhibits their wettability, the particles reaggregate to form larger particles due to their high surface free energy, extreme reduction in the particle size impart surface charges that may prevent wetting.
2. How the absolute surface area of hydrophobic drugs can be converted to their effective surface area?
a) Use of surfactant
b) Use of Hydrophobic diluents
c) Use of surfactant and hydrophilic diluents
d) No need of doing micronization
Explanation: Use of surfactant as a wetting agent decreases the interfacial tension and displaces the adsorbed air with the solvent and using hydrophilic diluents coat the surface and render them hydrophilic
3. Which one of these is not an example of hydrophilic diluents?
a) PVC
b) Dextrose
c) PVP
d) PEG
Explanation: PVC is polyvinyl chloride not used as a drug formulation. Hydrophilic diluents such as PEG < PVP, dextrose coat the surface of a hydrophobic molecule to give hydrophilic surface.
4. The solvate can exist in different crystalline forms called as _________
a) Solvates
b) Pseudopolymorphs
c) Pseudopolymorphism
d) Hydrate
Explanation: Stoichiometric type of adducts of the solid where the solvent molecules are incorporated into the crystal lattice of any solid are known as solvates. The solvates that can exist in different crystalline forms are known as pseudopolymorphs. The phenomenon is known as pseudopolymorphism.
5. Which form of a drug has greater solubility?
a) Anhydrous
b) Hydrate
c) Crystallised
d) Monohydrate
Explanation: Anhydrous form of a drug has a greater aqueous solubility than the hydrates. This is because the hydrates are already in interaction with the water and therefore have less energy for crystal breakup.
6. Which one will be the easiest approach to enhance the solubility and dissolution of any drug?
a) Micronize the drug
b) Convert drug into their anhydrous form
c) Convert drug into their hydrous form
d) Convert drug into their salt form
Explanation: Most drugs are weak acids or weak base3s. Thus, one of the easiest approaches to enhance the solubility and dissolution of any drug is to convert them into their salt forms
7. What is pH?
a) –ve log of H+ concentration
b) +ve log of H+ concentration
c) Log of H+ concentration
d) H+ concentration
Explanation: pH is a scale used to measure how much acidic or basic a solution is. PH is logarithmic and negative of the 10-base logarithm of the molar concentration of the hydrogen ions present
8. Which one of these is not an advantage of buffered aspirin tablets?
a) Enhanced bioavailability
b) Reduced gastric irritation
c) Increased stability
d) Increased ulcerogenic tendency
Explanation: Including enhanced bioavailability, buffered aspirin tablets have more two advantages that are, reduction of the gastric irritation and ulcerogenic tendency of the drug. And second is the stability is increased by in-situ salt formation
9. Larger the size of the counterion, greater the solubility.
a) True
b) False
Explanation: The size of the counterion influences the solubility of the salt forms. Smaller the size of the counterion greater the solubility of the salt. If the counter ion has a larger size or poor ionic strength, the solubility decreases to a large extent.
10.According to the pH-partition hypothesis which one of the given options doesn’t govern the absorption?
a) The molecular size of the drug
b) PH at the absorption site
c) Lipid solubility of unionized drugs
d) Dissociation constant
Explanation: The pH-partition hypothesis tells that for drug compounds with molecular weight more than 100, that are transported by passive diffusion across the cell membrane, the process is governed by the capability of lipid solubility of unionized drugs, the dissociation constant of the drug and pH at the absorption site.