General models for the joint action of mixtures of drugs.

This paper is concerned with the construction of mathematical models to represent the action of drugs or other stimuli on biological organisms or other complex systems. A framework for a general system of models is set up on the basis of three main concepts: the system and its subsystems, the sites of action, and the components of the stimulus. The classification of joint action in terms of this framework is then considered and a clarification of the standard nomenclature in relation to dependent joint action is put forward. A more specific set of models, based upon a simplified representation of drug-receptor action, is developed within the general framework. Some practical examples of joint action in the context of the models are described.