B.Pharm. Bachelor of Pharmacy Bachelor of Pharmacy (B.Pharm.) Pharmaceutics 5 — Questions and Answers
Question 1: Which excipient is used as a cryoprotectant in lyophilized protein formulations to prevent aggregation during freezing?
- Magnesium stearate
- Sucrose (Correct answer)
- Talc
- Sodium lauryl sulfate
Correct answer: Sucrose
Sucrose and trehalose stabilize proteins during freeze-drying by replacing hydrogen bonds lost when water is removed.
Question 2: The HLB (Hydrophilic-Lipophilic Balance) value range of 8–18 is preferred for surfactants used as:
- W/O emulsifiers
- Wetting agents
- O/W emulsifiers (Correct answer)
- Foam suppressants
Correct answer: O/W emulsifiers
High HLB values (8–18) indicate predominantly hydrophilic character, favoring formation of O/W emulsions.
Question 3: Transdermal drug delivery systems are most suitable for drugs with molecular weight less than:
- 100 Da
- 500 Da (Correct answer)
- 1000 Da
- 5000 Da
Correct answer: 500 Da
Skin permeation is generally limited to molecules below ~500 Da; larger molecules cannot efficiently cross the stratum corneum.
Question 4: Zero-order drug release from a dosage form means the drug is released at:
- A rate proportional to the remaining drug amount
- A constant rate independent of drug concentration (Correct answer)
- An exponentially decreasing rate
- A rate proportional to the square root of time
Correct answer: A constant rate independent of drug concentration
Zero-order release delivers a constant amount of drug per unit time, providing stable plasma concentrations.
Question 5: A pharmaceutical suspension that settles slowly and can be easily redispersed with gentle shaking is called a:
- Flocculated suspension (Correct answer)
- Deflocculated suspension
- Emulsion
- Colloidal dispersion
Correct answer: Flocculated suspension
Flocculated suspensions form loose aggregates (flocs) that sediment as a fluffy cake and redisperse easily.
Question 6: Which polymorphic form of a drug generally exhibits the highest aqueous solubility?
- Most stable crystalline polymorph
- Amorphous form (Correct answer)
- Hydrate
- Lowest-energy polymorph
Correct answer: Amorphous form
The amorphous form lacks long-range crystalline order, resulting in higher free energy and therefore greater solubility than crystalline forms.
Question 7: Osmotic pump tablets (OROS) control drug release by using:
- pH-dependent polymer dissolution
- Osmotic pressure to pump drug solution through a laser-drilled orifice (Correct answer)
- Erosion of a wax matrix
- Ion-exchange resin binding
Correct answer: Osmotic pressure to pump drug solution through a laser-drilled orifice
In OROS tablets, water influx through a semipermeable membrane generates osmotic pressure that pushes drug out through a drilled hole at a constant rate.
B.Pharm. Bachelor of Pharmacy Bachelor of Pharmacy (B.Pharm.) Pharmaceutics 5
Which excipient is used as a cryoprotectant in lyophilized protein formulations to prevent aggregation during freezing?