Maximum tolerated dose (MTD) / tolerability assay for Preclinical Research

Maximum tolerated dose (MTD) is the highest dose of a drug that doesn't cause unacceptable side effects or overt toxicity in a specific time period.
Determining the MTD during preclinical development is crucial for two main reasons: to ensure patient safety in future clinical trials and to guide the design of those trials.
At Vibiosphen, we provide robust MTD / tolerability models in rodents to support the development of novel antibiotics, antifungals, and antivirals. Our models are designed to generate clinically relevant data that help pharmaceutical, and biotechnology companies accelerate drug discovery and vaccine research.
 

Background of Maximum tolerated dose (MTD) / tolerability assay

The MTD (Maximum Tolerated Dose) assay in rodents is a fundamental, early-stage toxicology study designed to determine the highest dose of a new drug or compound that can be given without causing unacceptable adverse effects. This is a critical step in the drug development process.

This information is used to:

1. Set the Doses for Efficacy and Long-Term Studies: The MTD serves as the high dose for subsequent, more extensive toxicology studies, such as the 28-day, 90-day, or chronic toxicity studies required for regulatory submission.
2. Determine a Safe Starting Dose for Human Clinical Trials: The data from rodent MTD studies, along with other animal species data, are used to extrapolate a safe starting dose for Phase I clinical trials in humans.
3. Identify Target Organs for Toxicity: By observing which organs or systems show signs of damage at the MTD, the potential targets of toxicity can be identified. This informs the design of future studies and helps in the clinical monitoring of patients.
   MTD  is a critical, early go/no-go decision point in drug development.

Rodent Models of Maximum tolerated dose (MTD) / Tolerability

Mouse lineages

• The primary mouse lineages used in preclinical studies are inbred strains known for their genetic uniformity, which minimizes experimental variability.
  • C57BL/6 mice have a T-helper type 1 (Th1) biased immune response, which is a cellular immune response important for fighting intracellular pathogens and cancer.
  • BALB/c mice have a T-helper type 2 (Th2) biased immune response. A Th2 response is a humoral immune response that relies on antibodies and is essential for combatting extracellular parasites.
• Outbred mice, unlike their inbred counterparts, are maintained in large, randomly bred colonies to maximize genetic variation. This heterogeneity makes each mouse genetically unique.
  • CD-1 (also known as ICR) mice
  • Swiss mice

The decision to use an inbred or outbred strain depends on the specific research question. Inbred mice are for when you want to minimize all genetic variables and pinpoint the effect of a single factor. Outbred mice are for when you want to see how a factor affects a genetically varied population.

Rat lineages

• Inbred strain, meaning they are genetically uniform, and provide a consistent baseline for preclinical studies, which is essential for reproducibility.
  • Fischer 344 (F344) rats
• Outbred rats. They have a wide range of genetic variability, which better represents the genetic diversity found in the human population 
  • Sprague Dawley rats 
  • Wistar rats

The decision to use an inbred or outbred strain depends on the specific research question. Inbred rats are for when you want to minimize all genetic variables and pinpoint the effect of a single factor. Outbred rats are for when you want to see how a factor affects a genetically varied population.

Routes of Administration

Compounds under evaluation can be administered through several routes to reflect clinical usage and pharmacological profiles:

• Oral gavage 
• Intraperitoneal route
• Intravenous route
• Subcutaneous route
• Intramuscular route
• Intranasal route
• Inhalation / aerosolization route
• Intratracheal route
   

Readouts in MTD / tolerability Models

A study design can vary in complexity, from simple to sophisticated, because the choice of design depends on the specific research question being asked and the stage of drug development.

Body Weight Change
Clinical Signs
Clinical Pathology: Changes in blood and urine samples, including alterations in liver enzymes (e.g., ALT, AST), kidney function markers (e.g., creatinine, BUN), and hematology parameters (e.g., red and white blood cell counts).
Gross Pathology: Examination of the animal's organs at the end of the study for any visible abnormalities like discoloration, swelling, or lesions.
Histopathology: Microscopic examination of tissue for inflammation, tissue damage.

Why Choose Vibiosphen?

• Proven expertise in preclinical research
• Flexible and customized study designs adapted to sponsor requirements (see downloads available as example) 
• Advanced facilities to ensure reliable and reproducible results (BSL2 and BSL3) 
• Strong collaborations with pharmaceutical companies, biotech firms, and academic partners

Vibiosphen combines scientific excellence with industry know-how to deliver actionable preclinical data that drive innovation in infectious disease therapeutics.

Contact Us

If you are developing new treatments or vaccines, Vibiosphen can help accelerate your research.
Contact us today to discuss your project and explore how our MTD / Tolerability models can support your development strategy. 
We will be pleased to facilitate your project by providing a customized study design to your project objectives.