FPGEE Pharmaceutics 4

Question 1

Which excipient acts as both a binder and a disintegrant in direct compression tablet formulations?

Accepted Answer

Microcrystalline cellulose (MCC)

Answer

MCC provides excellent binding under compression and also promotes disintegration via wicking and swelling mechanisms.

Question 2

The Henderson-Hasselbalch equation predicts that a weak acid drug with pKa 4.0 in gastric fluid (pH 1.0) will be predominantly:

Accepted Answer

Unionized

Answer

When pH is much lower than pKa for a weak acid, the drug exists predominantly in the unionized form, favoring gastric absorption.

Question 3

A transdermal drug delivery system is designed to deliver drug at a constant rate through the skin. This BEST describes which type of system?

Accepted Answer

Membrane-controlled (reservoir) system

Answer

Reservoir (membrane-controlled) transdermal systems use a rate-controlling membrane to deliver drug at a near-constant (zero-order) rate.

Question 4

Which sterilization method is MOST suitable for heat-labile ophthalmic solutions?

Accepted Answer

Filtration through 0.22 μm membrane

Answer

Membrane filtration through a 0.22 μm filter removes microorganisms without exposing heat-labile drugs to high temperatures.

Question 5

Which phenomenon occurs when two incompatible drugs are mixed in solution and form an insoluble complex that precipitates?

Accepted Answer

Incompatibility precipitation

Answer

Incompatibility precipitation results from a chemical reaction between two drug components or a drug and excipient, forming an insoluble product.

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