Question

question 33

which of the following guidelines should a pharmacy technician consider when measuring a liquid ingredient?

liquid should be added with a syringe or pipette.
use the smallest device that will accommodate the liquid.
always measure an oily liquid by volume.
use a prescription bottle to measure the liquid.

Explanation:

Identify the core compounding principle

The question asks for the correct guideline a pharmacy technician should follow when measuring a liquid ingredient. In pharmacy compounding, accuracy is paramount. To minimize measurement error, the general rule is to select measuring equipment where the volume to be measured is as close as possible to the capacity of the device, without exceeding it.

Evaluate the options

• Option 1: "Liquid should be added with a syringe or pipette." While syringes and pipettes are used for small, precise volumes, they are not always the required or appropriate device for all liquid measurements (e.g., larger volumes measured in graduated cylinders).
• Option 2: "Use the smallest device that will accommodate the liquid." This aligns with standard pharmacy practice. Using a device closest in size to the volume being measured (e.g., using a 10 mL graduated cylinder instead of a 100 mL graduated cylinder to measure 8 mL) significantly reduces the percentage of measurement error.
• Option 3: "Always measure an oily liquid by volume." Oily or highly viscous liquids are often difficult to pour and measure accurately by volume due to clinging to the vessel walls. They are frequently measured by weight (mass) rather than volume for better accuracy.
• Option 4: "Use a prescription bottle to measure the liquid." Prescription bottles are not calibrated for accurate measurement and should never be used as a primary measuring device in compounding.

Apply the mastered concept

Using the Compounding Equipment knowledge point, we know that selecting the appropriate graduated cylinder, syringe, or beaker is critical for accuracy. The rule of thumb is to choose the smallest measuring vessel that can hold the desired volume to ensure the highest level of precision.

Answer:

• Liquid should be added with a syringe or pipette.
• Use the smallest device that will accommodate the liquid. (Correct answer)
• Always measure an oily liquid by volume.
• Use a prescription bottle to measure the liquid.