1-14. APOTHECARY VOLUME
The gallon, quart, pint, and fluid ounce of the apothecary system are the familiar
units used in the United States to measure liquids such as milk, gasoline, and soft
drinks. Table 1-8 provides some useful information on commonly encountered
apothecary volume units.
1 gallon (C. or gal.) =
4 quarts =
1 quart (qt.)
32 fluid ounces
1 pint (pt.)
16 fluid ounces (fl. oz. or
Table 1-8. Commonly encountered apothecary volume units.
Section V. CONVERSIONS
1-15. CONVERSION BETWEEN SYSTEMS
a. To convert quantities from one system of measurement to another, a familiar
tool, ratio and proportion, can be used. Table 1-9 contains some useful approximate
conversion factors. Remember, the conversion factors are approximate. When the
exact conversion factors are required (that is, when prescriptions are compounded),
pharmaceutical texts or references should be consulted.
1 kilogram (kg.)
1 grain (gr.)
60 milligrams (mg.)
1 fluid ounce (fl. oz.,
Table 1-9. Approximate conversion factors.
b. The process of converting from one system to another can be done with ease
if three steps are followed:
(1) Write the conversion factor as your IF ratio.
(2) Write the unknown factor as your THEN ratio.
(3) Solve for the unknown as in any ratio and proportion problem.