Find 1 percent of the total amount:
1 percent of 120 = 1.2
One percent of volume times the number of percent = Amount of
1.2 X 2 = 2.4 grams of ephedrine sulfate needed.
NOTE: When calculating percentage problems in the metric system, the unit
designation is dependent upon whether the active ingredient is a solid or a liquid.
Because ephedrine sulfate is a solid, the unit designation is grams.
(2) Example #2: How many grams of boric acid are needed to make 240 ml
of a 5% (w/v) boric acid solution?
The total amount of preparation is 240 ml.
1 percent of 240 = 2.4
2.4 X 5 = 12 grams of boric acid required.
(3) Example #3: How many grams of zinc oxide are needed to make 120
grams of 20% zinc oxide paste?
The total amount of the preparation is __________ grams.
1 percent of the total amount is ____________.
______X______ = ________ grams of zinc oxide needed.
The total amount of the preparation is 120 grams.
1 percent of the total amount is 1.2.
1.2 X 20 = 24 grams of zinc oxide required.