Question

a pharmacy technician receives a prescription for a compound order for 4 g of lidocaine (xylocaine) dissolved in a final volume of 50 ml of simple syrup. which of the following is the final percent strength (%w/v) of this prescription?

Explanation:

Step1: Recall the %w/v formula

The formula for percent - weight/volume (%w/v) is $\frac{\text{weight of solute (g)}}{\text{volume of solution (mL)}}\times100$.

Step2: Identify values

The weight of lidocaine (solute) is $4$ g and the volume of the simple syrup (solution) is $50$ mL.

Step3: Substitute values into formula

$\frac{4\text{ g}}{50\text{ mL}}\times100=\frac{400}{50}=8\%$

Answer:

8% (w/v)