Drug Biotechnology Multiple Choice Questions on “Biopharmaceuticals – Oral Controlled Release Systems”.
1. Oral controlled release drugs release the drug only inside the intestine.
a) True
b) False
Answer: b
Clarification: Continuous release systems release the drug for a prolonged period of time. The drug will be releasing components along the whole length of the GIT with normal transit of the dosage form. It releases the drug especially up to the terminal region of the small intestine.
2. What are the characteristics of continuous release systems?
a) Release the drug along the entire length of GIT
b) Prolonged their residence in the GIT and release
c) Release only at a specific drug
d) Release as soon as comes in contact to the saliva
Answer: b
Clarification: Continuous releasing system prolong the residence time of the drug in the GIT of the patient. Thus it gives prolong the period for the drug to dissolve slowly. This type of system can increase the therapeutic time and thus the dosage will be reduced.
3. What is the characteristic of delayed transit and continuous release systems?
a) Release the drug along the entire length of GIT
b) Prolonged their residence in the GIT and release
c) Release only at a specific drug
d) Release as soon as comes in contact to the saliva
Answer: b
Clarification: Delayed transit and continuous release systems are designed to prolong their residence in the GIT along with the increase of releasing time. Most of the time the dosage form is fabricated to retain in the stomach and hence the drug present therein should be stable at gastric pH.
4. What is the characteristic of delayed release systems?
a) Release the drug along the entire length of GIT
b) Prolonged their residence in the GIT and release
c) Release only at a specific drug
d) Release as soon as comes in contact to the saliva
Answer: c
Clarification: The design of delayed release systems involves the release of the drug only at a specific site in the GIT. The drugs which are included in such system are destroyed in the stomach or by intestinal enzymes. These drugs are known to gastric distress and absorbed from a specific intestinal site.
5. What is the characteristic of dissolution controlled release systems?
a) Release the drug along the entire length of GIT
b) Prolonged their residence in the GIT and release
c) Release only at a specific drug
d) Very slow dissolution rate
Answer: d
Clarification: Dissolution controlled release system is easiest to design. The drug of such system may be inherently slow dissolution, such drugs act as natural prolonged release products. These drugs form slow dissolving forms when it comes in contact with GI fluids. These drugs have high aqueous solubility.
6. What is the characteristic of matrix dissolution-controlled release systems?
a) Release the drug along the entire length of GIT
b) Prolonged their residence in the GIT and release
c) Release only at a specific drug
d) Employ waxes to control the rate of dissolution
Answer: d
Clarification: Matrix drugs are homogenous drugs since they are dispersed throughout the drug in a rate controlling medium. They employ wax such as beeswax, hydrogenated castor oil, etc. the drug is often first order from such matrixes. The wax embedded drug is prepared by dispersing the drug in molten wax and granulating it.
7. What is the characteristic of encapsulation or coating dissolution-controlled release systems?
a) Microencapsulation using slowly dissolving materials
b) Prolonged their residence in the GIT and release
c) Release only at a specific drug
d) Employ waxes to control the rate of dissolution
Answer: a
Clarification: When drugs are encapsulated with slowly dissolving materials such as that of cellulose, PEG, waxes, etc. The pellets may be filled up in hard gelatin capsules and then compresses to form into tablets. The dissolution rate of the coat depends upon the solubility and thickness of the coat.
8. What are the characteristics of diffusion-controlled release systems?
a) Release the drug along the entire length of GIT
b) Diffusion of the dissolved drug
c) Release only at a specific drug
d) Employ waxes to control the rate of dissolution
Answer: b
Clarification: The rate controlling step is the diffusion of the dissolved drug through a polymeric barrier. The drug release rate is never 0. The diffusional path length increases with time as the insoluble matrix gradually depletes from the drug. Two types of diffusion-controlled systems are matrix systems and reservoir systems.
9. What are the characteristics of Matrix diffusion-controlled release systems?
a) Release the drug along the entire length of GIT
b) Drug disperse in an insoluble matrix of rigid hydrophobic materials
c) Release only at a specific drug
d) Employ waxes to control the rate of dissolution
Answer: b
Clarification: In this system, the drug is dispersed into an insoluble matrix of a rigid nonswellable hydrophobic material or swellable hydrophilic material. Materials such as insoluble plastic PVC and fatty acids are used as rigid matrix. The drug is generally kneaded with the plastic material.
10. What are the characteristics of reservoir devices-controlled release systems?
a) Release the drug along the entire length of GIT
b) Drug disperse in the insoluble matrix of rigid hydrophobic materials
c) Hollow systems containing drug surrounded by a polymer membrane
d) Employ waxes to control the rate of dissolution
Answer: c
Clarification: These systems are hollow which contains an inner core of drug surrounded in a water-insoluble polymer membrane. The drug release mechanism involves partitioning into the membrane with subsequent release into the surrounding fluid by diffusion.
11. What are the characteristics of ion exchange resin drug complexes?
a) Release the drug along the entire length of GIT
b) Drug disperse in an insoluble matrix of rigid hydrophobic materials
c) Hollow systems containing drug surrounded by a polymer membrane
d) Formation of complexes between the drug and anion/cation exchange resins
Answer: d
Clarification: Ionisable acidic and basic drugs are complexed with insoluble anion or cation exchange resins. The drug is released slowly by diffusion through the resin particle. Thus the controlled released of the drug is maintained. Drugs such as noscapine have been utilized by such methods.
12. What is the characteristic of pH-independent formulations?
a) Buffering agents that adjust pH to the desired value
b) Drug disperse in the insoluble matrix of rigid hydrophobic materials
c) Hollow systems containing drug surrounded by a polymer membrane
d) Formation of complexes between the drug and anion/cation exchange resins
Answer: a
Clarification: pH independent formulations are designed such that they can eliminate any changes in the drug property by the changing GI pH. This is done by formulating them with sufficient amount of buffering agents such as phosphoric acid, tartaric acid, citric acids. These formulations adjust the pH to the desired value.
13. What are the characteristics of osmotic pressure-controlled systems?
a) Buffering agents that adjust pH to the desired value
b) Releases the drug at a zero-order kinetics
c) Hollow systems containing drug surrounded by a polymer membrane
d) Formation of complexes between the drug and anion/cation exchange resins
Answer: b
Clarification: Osmotic pressure-controlled systems works on the principle of osmotic pressure to release the drug at a constant zero order rate. The core of the system comprises of the drug and osmotically active substance which will be surrounded by a rigid semipermeable membrane coating.
14. Osmotic pressure controlled systems work on the principle of osmotic pressure releasing the drug at constant 1st order kinetics.
a) True
b) False
Answer: b
Clarification: Osmotic pressure controlled systems are formulated such that they release the drug constantly at a zero order rate. The core comprises of the drug and an osmotically active substance such as potassium chloride or mannitol which will be surrounded by a rigid semipermeable membrane coating such as ester or cellulose ester.
15. What are the characteristics of hydrodynamic pressure controlled systems?
a) Buffering agents that adjust pH to the desired value
b) Drug disperse in an insoluble matrix of rigid hydrophobic materials
c) Generated by swelling hydrophilic hum
d) Formation of complexes between the drug and anion/cation exchange resins
Answer: c
Clarification: In hydrodynamic pressure controlled systems we use the hydrodynamic pressure generated by swelling a hydrophilic gum. The formulation comprises of rigid, shape-retaining house enclosing a collapsible, impermeable compartment containing the liquid drug. The systems are also called push-pull osmotic pumps.