Classification of plain preparations

Plain/monovalent preparations are defined as:

Preparations containing one active component (including stereoisomeric mixtures), and additional substances intended to

• increase the stability of the preparations (e.g. acetylsalicylic acid + ascorbic acid), or
• increase the duration of the effect (e.g. depot formulations), or
• increase the absorption of the active component (e.g. different solvents in dermatologicals).

Different salts of the active ingredient are usually given one and the same 5th level ATCvet code, but prodrugs and stereoisomers with differing pharmacological activity may be assigned separate 5th level codes.