The reagents, test solutions and volumetric solutions mentioned in the International Pharmacopoeia are described below. The reagents are denoted by the abbreviation R, the test solutions by the abbreviation TS and the volumetric solutions, or solutions that are similarly standardized, by the abbreviation VS. Similarly-named reagents differing in composition, purity, etc., are distinguished by placing a numeral after the appropriate abbreviation. The designations AsR, AsTS, ClTS, FeTS and PbTS refer to reagents of suitable purity for use in the limit tests for arsenic, chlorides, iron and heavy metals, respectively. The designation IR refers to reagents of suitable purity for use in spectrophotometry in the infrared region. The designation Cm denotes culture media for microbiological tests.

The designation RS denotes reference substance, in particular, but not exclusively International Chemical Reference Substances (ICRS). ICRS are available from the WHO collaborating host organization for International Chemical Reference Substances: European Directorate for the Quality of Medicines & HealthCare (EDQM), 7 allée Kastner, CS 30026, F-67081 Strasbourg, France; fax: +33 (0)3 88 41 27 71 – for the attention of EDQM Sales Section; email: orders@edqm.eu. A list of available ICRS is published on the EDQM website (www.edqm.eu). The concentrations are expressed in conformity with the Système international d'Unit(c)s (SI) and they refer to the anhydrous substance. The reference to SRIP indicates Specifications for reagents mentioned in The International Pharmacopoeia (World Health Organization, Geneva, 1963). Designations used in SRIP but now discontinued are given in square brackets. The designation d denotes the relative density , i.e. measured in air at 20 °C in relation to water at 20 °C.

Unless otherwise specified, all solutions indicated in the tests and assays of The International Pharmacopoeia are prepared with water R.