‘Optimal’ designs for drug, neurotransmitter and hormone receptor assays

The present paper reports the use of computer simulations of ligand–receptor interactions to evaluate the robustness of D‐optimal designs for receptor assays when these designs are based on unrealistic models for ligand binding. Particular attention is paid to the assumed distribution of the measurement errors together with complications caused by ‘non‐specific’ binding of a radioligand to a tissue or cell preparation. It is the latter factor which suggests that an optimal design for estimation of the parameters of a simple hyperbolic dose–response curve is nowhere near to being optimal in practice.