souseikai global clinical research center

DDI(Drug Drug Interaction) Studies

According to authorities world wide, conducting DDI studies before proceeding to Phase 3 clinical trials is recommended to successfully develop new drugs.

SOUSEIKAI Global Clinical Research Center was one of the first to recognize the importance of DDI studies, and has spent enormous effort conducting DDI studies safely and efficiently. To date, we have conducted 71 DDI studies including 12 independent clinical research in compliance with FDA Drug Interaction Study Guidance.

In vivo human DDI studies comparing substrate concentrations with or without the interacting drugs can vary a great deal, and need to be designed very carefully.

We have a lot of experience and know-how in selecting reference drugs for DDI studies, including so called "cocktail administration", and have been working hard to help find optimal study designs, including drug choices and doses.


  • Investigational Drug × Itraconazole
  • Investigational Drug Midazolam
  • Investigational Drug Atorvastatin
  • Investigational Drug Prednisolone

Cocktail Administration such as

  • Investigational Drug × Theophilin
  • Investigational Drug Tadalafil
  • Investigational Drug Efavirenz
  • Investigational Drug Repaglinide
  • Investigational Drug diclofenac Na.

ddi clinical trial