IND Application: The Purpose of IND-Enabling Studies

Every new drug candidate must undergo an Investigational New Drug (IND) application before it can be administered in human clinical trials. The IND application is submitted to the Food and Drug Administration (FDA). It includes several assays known as IND-enabling studies that prove the drug candidates potency and safety for humans.

IonTox offers several in vitro assays that support this application. Each assay comes with its own final report, and IonTox will also provide advice on follow-up assays to ease the manufacturer's application process. 

What is IND: Investigational New Drug (IND) Application Explained

According to the FDA, a drug must go through the Investigational New Drug (IND) application process to move on to the clinical trial phase, where it is tested in people. 

To get IND approval, the application needs to contain detailed information regarding the drug compound’s potency, its reasonable safety in animal studies, and the manufacturer’s ability to produce it with consistency. It must also include the clinical protocols and the qualifications of the clinical investigators who will conduct the trials. 

IND Studies and the Drug Development Process 

Suffice it to say, IND studies are a mandatory part of drug development. Here is what they entail. 

What Are IND-Enabling Studies? 

IND-enabling studies are assays that aim to measure a new drug’s safety for initial use in human clinical trials. These IND studies provide detailed information about each drug's dynamics, kinetics, and toxicity potential. They can be performed either in vivo (i.e. in living organisms) or in vitro (i.e. in cultured cells). In vitro assays are usually preferred due to their efficiency, lower cost, and fewer ethical considerations.

What About Pre-IND Enabling Studies?

During the early stages of the drug development process, a sponsor may partake in a pre-IND consultation meeting with the FDA. This meeting is mainly conducted to save time and resources for novel therapeutic drugs. The sponsor gains access to preclinical data from previous trials and studies and identifies the necessary testing required for an IND approval.

Key IND and Pre-IND Studies for Drug Development 

A complete IND application requires several key studies to gather data on the drug's pharmacodynamics, pharmacokinetics, and toxicity potential.

IND-Enabling Studies in Drug DevelopmentPharmacodynamics

Pharmacodynamics assays pertain to a drug’s effect and intensity in the human body in relation to its concentration or exposure time. Data from these assays is fundamental in order to establish dosing during the initial clinical trials.

A new drug must also undergo safety pharmacology tests to examine its effects on different animal tissues, including the central nervous and cardiovascular systems.


Pharmacokinetics (PK) assays study the metabolism and potential toxic effects of a particular drug in the human body. An IND study can include several PK assays depending on the phase of the drug development process, as well as the drug compound itself.

During the latter stages of clinical trials, additional assays that study drug-drug interactions (DDI) and absorption, distribution, metabolism, and excretion (ADME) properties are usually required.


Toxicology assays are essential to determine the maximum dosage and the long-term effects of drug exposure. Acute (single dose) toxicity testing is usually conducted before the initial clinical trials and is one of the most critical IND-enabling studies. 

Extensive assays on repeated-dose toxicity should also be carried out over long periods. These tests attempt to replicate the clinical trial process with similar duration, doses, and administration routes to determine the long-term toxicity potential of the drug.

What IND-Enabling Studies Does IonTox Offer? 

IonTox provides extensive help with IND applications through several in vitro ADME-PK assays. We can also support companies with their application through feedback and follow-up assays to improve the possibility of FDA acceptance.

Caco-2 Permeability

The Caco-2 permeability assay provides data on oral absorption and intestinal permeability of a drug. Testing can be run both unidirectionally and bidirectionally and is supervised by a Diplomat of the American Board of Toxicology.

Plasma Protein Binding & Blood Partitioning 

The Protein Binding assay provides knowledge on a drug’s tendency to bind to proteins in the plasma or cause blood partitioning, both of which can alter its therapeutic effect. Data from this assay can help choose the proper sample to assess pharmacokinetic and ADME properties.

Metabolic Stability

The metabolic stability assay measures the half-life and clearance of a drug compound when it is metabolized in the liver. Depending on the molecule type, the test can be conducted using microsomes, blood, or hepatocyte models.

CYP Induction & CYP Inhibition 

These assays measure the ability of a compound to inhibit or induce the CYP enzymes, which are crucial in drug metabolism. The data from these assays can help predict potential drug-drug interactions between the test compound and other compounds.

Transporter Interactions

Hepatic transporters are essential in both pharmacodynamics and pharmacokinetics. The transporter interactions assay provides knowledge on the interactions of a new drug with hepatic transporters.

IonTox - In Vitro Specialists 

IonTox is one of the leading authorities in the realm of in vitro toxicology. We can be your partner in your IND application with in vitro assays that support the process. We can help you bring your drug candidate to market safely and efficiently. 

We provide our services to a vast client base worldwide, in various sectors, including the pharmaceutical industry.

IonTox aims to broaden human knowledge and provide its clients with fast, dependable solutions for toxicology problems by improving existing in vitro toxicology methods and establishing new ones.

Contact us if you want to learn how IonTox can help you. One of our scientists will be more than happy to assist you.