ABSTRACT
<p><b>OBJECTIVE</b>An approach is set up to calculate pharmacodynamic interaction and simulate the combined response.</p><p><b>METHOD</b>An orthogonal design with 1-level = high dose and 2-level = low dose was adopted. An example of the compound with four components was applied to evaluate this quantitative approach. The bias was evaluated by the both scatter plots.</p><p><b>RESULT</b>This approach can calculate the value of each component with different dose by its contribution to combined response, and the value is related to the importance of a compound. Drug interactions were evaluated among the combinations in each group. The prediction model performed well and simulated the combined response in the different of components in combination.</p><p><b>CONCLUSION</b>The approach can be used in the similar research, and it also provides predictions of component combinations from the other studies by simulation.</p>