INTERNATIONAL SYSTEM OF UNITS (SI)

INTERNATIONAL SYSTEM OF UNITS (SI)
The International System of Units comprises three classes of units, namely base units, derived units and supplementary units1. The base units and their definitions are set out in Table 1.6-1.
The derived units may be formed by combining the base units according to the algebraic relationships linking the corresponding quantities. Some of these derived units have special names and symbols. The SI units used in the European Pharmacopoeia are shown in Table 1.6-2.
Some important and widely used units outside the International System are shown in Table 1.6-3.
The prefixes shown in Table 1.6-4 are used to form the names and symbols of the decimal multiples and submultiples of SI units.
NOTES
1. In the Pharmacopoeia the Celsius temperature is used (symbol t). This is defined by the equation
where T0 = 273.15 K by definition. The Celsius or centigrade temperature is expressed in degree Celsius (symbol °C). The unit "degree Celsius" is equal to the unit "kelvin".
2. The practical expressions of concentrations used in the Pharmacopoeia are defined in the General Notices.
3. The radian is the plane angle between two radii of a circle which cut off on the circumference an arc equal in length to the radius.
4. In the Pharmacopoeia conditions of centrifugation are defined by reference to the acceleration due to gravity (g):
5. Certain quantities without dimensions are used in the Pharmacopoeia: relative density (2.2.5), absorbance (2.2.25), specific absorbance (2.2.25) and refractive index (2.2.6).
6. The microkatal is defined as the enzymic activity which, under defined conditions, produces the transformation (e.g. hydrolysis) of 1 micromole of the substrate per second.
1 The definitions of the units used in the International System are given in the booklet "Le Système International d'Unités (SI)" published by the Bureau International des Poids et Mesures, Pavillon de Breteuil, F-92310 Sèvres.
Additions
The following monographs of the British Pharmacopoeia 2003 were not included in the British Pharmacopoeia 2002.