WEIGHTS AND MEASURES
The International System of Units (SI)is used in this Pharmacopeia.The SImetric and other units,and the symbols commonly employed,are as follows.
 Bq =becquerel L=liter kBq =kilobecquerel mL=milliter,‡ MBq =megabecquerel µL=microliter GBq =gigabecquerel Eq =gram-equivalent weight Ci =curie mEq =milliequivalent mCi =millicurie mol =gram-molecularweight (mole) µCi =microcurie Da =dalton (relativemolecular mass) nCi =nanocurie mmol =millimole Gy =gray Osmol =osmole mGy =milligray mOsmol =milliosmole m =meter Hz =hertz dm =decimeter kHz =kilohertz cm =centimeter MHz =megahertz mm =millimeter V=volts µm =micrometer(0.001mm) MeV=million electronvolts nm =nanometer * keV=kilo-electron volt kg =kilogram mV=millivolt g =gram ** psi =pounds per square inch mg =milligram Pa =pascal µg;mcg =microgram † kPa =kilopascal ng =nanogram g =gravity (incentrifugation) pg =picogram fg =femtogram dL=deciliter *  Formerly the symbol mµ(for millimicron)was used. **  The gram is the unit of mass that is used to measure quantities of materials.Weight,which is a measure of the gravitational force acting on the mass of a material,is proportional to,and may differ slightly from,its mass because of the effects of factors such as gravity,temperature,latitude,and altitude.The difference between mass and weight is considered to be insignificant for compendial assays and tests,and the term “weight”is used throughout USPand NF. †  Formerly the abbreviation mcg was used in the Pharmacopeial monographs;however,the symbol µg now is more widely accepted and thus is used in this Pharmacopeia.The term “gamma,”symbolized by g,is frequently used for microgram in biochemical literature. NOTE—The abbreviation mcg is still commonly employed to denote microgram(s)in labeling and in prescription writing.Therefore,for purposes of labeling,“mcg”may be used to denote microgram(s). ‡  One milliliter (mL)is used herein as the equivalent of 1cubic centimeter (cc).