When a drug is suspended in an oil vehicle, the combination is called the bolus.

When a drug is suspended in an oil vehicle, the combination is called the bolus.

• A. Solution
• B. Bolus
• C. Suspension
• D. Vehicle

Answer: (B)

The term bolus refers to a single-dose dosage form that is typically an oil-based mass in which the drug is not dissolved but suspended. When the drug particles are dispersed in an oil vehicle rather than dissolved, you’re forming a bolus—a one-shot, viscous preparation designed for administration as a single dose. This is different from a solution, where the drug is dissolved in the solvent; or a suspension, where solid particles are simply dispersed in a liquid but not in oil specifically; and it’s not just the vehicle itself, which is the oil base used to deliver the drug.

The term bolus refers to a single-dose dosage form that is typically an oil-based mass in which the drug is not dissolved but suspended. When the drug particles are dispersed in an oil vehicle rather than dissolved, you’re forming a bolus—a one-shot, viscous preparation designed for administration as a single dose. This is different from a solution, where the drug is dissolved in the solvent; or a suspension, where solid particles are simply dispersed in a liquid but not in oil specifically; and it’s not just the vehicle itself, which is the oil base used to deliver the drug.