MPharm Master of Pharmacy Master of Pharmacy: Pharmaceutical Formulations and Dosage Forms 3

Question 1

Fick's first law of diffusion relates steady-state flux (J) to which variables?

Accepted Answer

J = –D × dC/dx (diffusion coefficient × concentration gradient)

Answer

Fick's first law states J = –D(dC/dx), where flux is proportional to the diffusion coefficient and the negative concentration gradient across the membrane.

Question 2

Which polymorphic form of a drug is generally preferred for formulation due to its thermodynamic stability?

Accepted Answer

Stable polymorph

Answer

The most stable polymorph has the lowest solubility but the highest physical stability, reducing the risk of form conversion during processing and storage.

Question 3

In the Noyes-Whitney equation, which factor most directly increases the dissolution rate of a poorly soluble drug?

Accepted Answer

Decreasing the diffusion layer thickness (h)

Answer

The Noyes-Whitney equation shows dissolution rate ∝ D×A×Cs/h; reducing diffusion layer thickness (e.g., by agitation or micronization) directly increases rate.

Question 4

A transdermal patch designed for zero-order drug delivery typically uses which design?

Accepted Answer

Reservoir-type patch with a rate-controlling membrane

Answer

Reservoir patches contain drug in a solution or gel depot separated from skin by a rate-controlling membrane that maintains constant flux (zero-order release).

Question 5

Which excipient functions as a glidant to improve powder flow during tablet manufacturing?

Accepted Answer

Colloidal silicon dioxide (Aerosil)

Answer

Colloidal silicon dioxide reduces interparticle friction by coating powder surfaces, improving flow through hoppers and tablet press feeders.

MPharm Master of Pharmacy Practice Test

MPharm Master of Pharmacy Practice Test

MPharm Master of Pharmacy Master of Pharmacy: Pharmaceutical Formulations and Dosage Forms 3