Pharmaceutics Flashcards

Which dissolution model describes drug release that is proportional to the square root of time?

Answer: Higuchi model

The Higuchi model describes diffusion-controlled drug release from a matrix, where cumulative release is proportional to the square root of time.

A tablet formulation requires a disintegrant that swells rapidly upon contact with water. Which excipient is MOST appropriate?

Answer: Sodium starch glycolate

Sodium starch glycolate is a superdisintegrant that rapidly swells in water, promoting tablet disintegration.

What is the primary purpose of an enteric coating on an oral solid dosage form?

Answer: Prevent drug release in the stomach

Enteric coatings resist dissolution at low gastric pH but dissolve at the higher pH of the small intestine, protecting acid-labile drugs or preventing gastric irritation.

In a parenteral emulsion intended for intravenous administration, the droplet size of the dispersed phase must not exceed:

Answer: 5 microns

IV emulsions must have droplet sizes below 5 microns to prevent capillary occlusion and ensure safe intravenous administration.

Which factor primarily determines whether a drug is classified as BCS Class I?

Answer: High solubility and high permeability

BCS Class I drugs have both high aqueous solubility and high intestinal permeability, making them ideal candidates for biowaivers.

The van't Hoff equation is used in pharmacy to calculate:

Answer: Osmotic pressure of a solution

The van't Hoff equation (π = iMRT) relates osmotic pressure to molar concentration, temperature, and the number of solute particles.

A cream formulation is classified as an oil-in-water (O/W) emulsion. Which of the following is a characteristic of this type?

Answer: It is water-washable

O/W emulsions have water as the external phase, making them water-washable, non-greasy, and easy to spread.