Q: Which equation best represents the relationship between viscosity ($$\eta$$), shear stress ($$\tau$$), and shear rate ($$\dot{\gamma}) $$for a Newtonian fluid?

$$\eta = \frac{\tau}{\dot{\gamma}}$$

Question 1

Which of the following statements best describes the distinguishing feature of a paste compared to an ointment?

Accepted Answer

Pastes contain a higher concentration of insoluble powdered substances, usually 20% or more, making them thicker and more protective than ointments.

Question 2

Which type of ointment base is most appropriate for a drug that is hydrolyzed by water and needs to remain stable for extended periods?

Accepted Answer

Oleaginous base

Question 3

A patient needs a topical medication that is easily spreadable, water-washable, and non-greasy. Which base should be selected?

Accepted Answer

Oil-in-water (O/W) emulsion base

Question 4

Which of the following is a sign of physical instability in a semisolid dosage form?

Accepted Answer

Crystal growth

Question 5

Which rheological property describes a system where viscosity decreases with increasing shear stress, commonly seen in creams?

Accepted Answer

Pseudoplastic flow

Question 6

What is the main reason why water-in-oil (W/O) emulsion bases are not water-washable?

Accepted Answer

The oil is the bulk phase, making the base hydrophobic and insoluble in water.

Question 7

Which of the following factors will increase the systemic absorption of a drug applied topically?

Accepted Answer

Increasing the surface area of application

Question 8

Which method is used to reduce the particle size and grit of powders when compounding ointments?

Accepted Answer

Levigation

Question 9

A pharmacist is compounding an ointment using the fusion method. Which step should be performed last?

Accepted Answer

Adding heat-labile materials

Question 10

Which of the following is NOT an ideal physical property of a semisolid dosage form?

Accepted Answer

Gritty texture

Question 11

Which base is most likely to be stored in the refrigerator due to its tendency to melt at room temperature?

Accepted Answer

Cocoa butter (Theobroma oil)

Question 12

Which phenomenon describes a time-dependent shear thinning property, where viscosity decreases over time when agitated?

Accepted Answer

Thixotropy

Question 13

Which of the following is a correct statement about water-soluble ointment bases?

Accepted Answer

They are lipid-free and can absorb a limited amount of water.

Question 14

A patient is allergic to wool alcohols. Which ointment base should be avoided?

Accepted Answer

Oleaginous base containing lanolin

Question 15

Which of the following is a pharmaceutical factor that affects drug penetration through the skin?

Accepted Answer

Physicochemical properties of the drug and the vehicle

Question 16

Which equation best represents the relationship between viscosity ($$\eta$$), shear stress ($$	au$$), and shear rate ($$\dot{\gamma}) $$for a Newtonian fluid?

Accepted Answer

$$\eta = \frac{	au}{\dot{\gamma}}$$

Question 17

Which type of emulsion is best described as having water as the bulk phase and is water-washable?

Accepted Answer

Oil-in-water (O/W) emulsion

Question 18

Which of the following is a correct statement about the use of excipients in semisolid dosage forms?

Accepted Answer

Excipients such as emulsifiers, viscosity increasing agents, antimicrobials, and antioxidants are commonly included to improve stability and performance.

Question 19

Which of the following statements about geometric dilution is correct?

Accepted Answer

It is a method used to ensure uniform distribution of a small amount of potent drug throughout a larger amount of base.

Semisolid Dosage Forms: Ointments, Creams, Gels, and Suppositories

Study Guide - Practice Questions

Study Guide - Flashcards