What is the amount of local anesthetic in one cartridge of 2% lidocaine (1.8 ml)?

To determine the amount of local anesthetic in one cartridge of 2% lidocaine, it is important to understand how concentrations work. A solution that is 2% lidocaine means that there are 2 grams of lidocaine in every 100 ml of solution. Since one cartridge contains 1.8 ml of 2% lidocaine, we can calculate the amount of lidocaine present in that specific volume.

First, convert the percentage concentration to milligrams for easier calculation:

2% can be converted to mg/ml as follows:

2 grams = 2000 mg.

Since this is contained in 100 ml, this translates to:

2000 mg ÷ 100 ml = 20 mg/ml.

In one cartridge, which is 1.8 ml, the amount of lidocaine can be calculated by multiplying:

20 mg/ml × 1.8 ml = 36 mg.

Thus, one cartridge of 2% lidocaine (1.8 ml) contains 36 mg of lidocaine. This makes the answer correct because it properly reflects the volume and concentration of the local anesthetic in question.