In this protocol, we will focus on an in vivo single-dose toxicity study using mice as a the model for assessing toxicity of the test article.

Research Objective

To evaluate the acute toxicity of the test article and determine its potential adverse effects on mice after a single administration.

Materials and Equipment

  1. Laboratory mice (appropriate strain, age, and sex)
  2. Test article (the substance to be tested)
  3. Control article (an inert substance or vehicle)
  4. Precision balance
  5. Syringes and needles (if required for administration)
  6. Recording sheets or electronic data recording system
  7. Analytical equipment for sample analysis (if necessary)

Experimental Design

  1. Mice are randomly assigned to treatment groups, including a control group and several test groups, with each group consisting of an adequate number of animals (typically at least 5 per group).
  2. Mice in the control group receive the vehicle or an inert substance, while mice in the test groups receive different doses of the test article.


  1. Prior to the study, acclimate the mice to the laboratory conditions for at least one week. At AniLocus, we have a standard acclimation period of 2-4 weeks.
  2. Ensure that the mice have access to food and water ad libitum during the acclimatization period and throughout the study.
  3. Calculate the appropriate dosages based on body weight, and prepare the test article and control article solutions according to the dosing regimen.
  4. Administer the test article and control article by the chosen route (e.g., oral gavage, intraperitoneal injection, etc.) in a single dose to the respective groups. Note the exact dose, route, and time of administration.
  5. Observe the mice closely for the following parameters at specified time points (e.g., 0, 1, 2, 4, 8, 24 hours post-administration): General behavior (activity, grooming, etc.); Clinical signs of toxicity (e.g., tremors, ataxia, piloerection); Mortality; Body weight changes; Food and water consumption

Sample Collection (if necessary)

  1. If required, collect blood or tissue samples at specific time points post-administration for further analysis (e.g., serum chemistry, histopathology). Keep this information in mind when selecting the number of animals required for power analysis and for minimum volume of sample required for analysis. Contact us for more information about this type of analysis.
  2. Euthanize animals as per ethical guidelines and regulatory requirements.

Data Analysis

  1. Record all observations and measurements in a systematic manner.
  2. Analyze the data statistically, comparing the test article groups to the control group.
  3. Calculate LD50 (if relevant) and determine the dose-response relationship.

Final Reporting

  1. Prepare a comprehensive report summarizing the study design, methods, results, and conclusions.
  2. Discuss any adverse effects observed, dose-response relationships, and potential implications for human exposure.
  3. Include recommendations for further testing or risk assessment, if applicable.

Ethical Considerations

  1. Conduct the study in compliance with ethical guidelines for animal research and obtain the necessary approvals from the Institutional Animal Care and Use Committee (IACUC) or equivalent body.
  2. Each in vivo animal study conducted at AniLocus requires IACUC approval. This approval process is typically 30 days prior to study commencement (unless otherwise noted).

Safety Precautions

  1. Handle the test article with care and follow safety protocols for hazardous substances.
  2. Use appropriate personal protective equipment (PPE) when handling animals and substances.
  3. AniLocus requires test article characterization prior to administration to test subjects for safety and ethical considerations. Please read this article about Test Article Characterization Requirements.

Parameters to Measure:

  • Clinical Signs: Observe and record any clinical signs of toxicity, such as changes in behavior, appearance, and movement (e.g., tremors, seizures, lethargy, ataxia).
  • Mortality: Monitor and record the number of deaths in each treatment group over the observation period.
  • Body Weight: Measure and record the body weight of mice before dosing and at specified time points post-administration to detect any weight loss or gain.
  • Food and Water Consumption: Monitor and record changes in food and water intake, which can be indicative of toxicity-related anorexia or polydipsia.
  • Hematological Parameters (if collected): Parameters may include complete blood count (CBC) with differential counts to assess potential hematological effects.
  • Serum Chemistry (if collected): Assess biochemical parameters, such as liver enzymes (ALT, AST), kidney function markers (creatinine, BUN), and electrolytes.
  • Histopathology (if collected): Examine tissues from necropsy for pathological changes, such as organ damage or inflammation. Learn more about our histology services and special stains.

Documentation to Prepare for Single-Dose Toxicity Study

  • Study Design: Record details of the study design, including dosing regimen, route of administration, and treatment groups.
  • Animal Information: Document the age, sex, strain, and identification numbers of the mice used.
  • Dosing Information: Record the exact doses of the test and control articles administered to each group.
  • Observations: Maintain detailed records of daily observations, including clinical signs, mortality, and any abnormal behavior.
  • Body Weight and Food/Water Consumption Data: Record these measurements at specified time points.
  • Sample Collection Data (if applicable): Document the collection of blood or tissue samples, including the time of collection and handling procedures.
  • Data Analysis: Include statistical analyses and calculations of LD50 (if relevant) in the documentation.

Implications of Potential Results from Single-Dose Toxicity Study

  • No Toxicity Observed: If no adverse effects are observed in the treated groups, it suggests that the test article is relatively safe at the administered doses.
  • Dose-Dependent Toxicity: If toxicity is observed in a dose-dependent manner, it implies that the substance’s toxicity is related to the dose level.
  • Lethal Dose (LD50): Determination of LD50 can provide valuable information for risk assessment and classification of toxicity levels.
  • Specific Organ Toxicity: If specific organ toxicity is observed (e.g., hepatotoxicity or nephrotoxicity), it may indicate target organ effects.

Pharmaceutical Therapies Assessable with Toxicity Studies

  • New Drug Candidates: Assess the acute toxicity of new pharmaceutical compounds to determine their safety profiles at early stages of development.
  • Biologics: Evaluate the safety of biopharmaceuticals, such as monoclonal antibodies or gene therapies, to identify potential adverse effects.
  • Vaccines: Assess the safety of vaccine candidates, including potential side effects and adverse reactions.
  • Chemotherapeutic Agents: Evaluate the acute toxicity of chemotherapy drugs and their potential impact on vital organs.
  • Therapeutic Agents with Narrow Therapeutic Windows: Assess the safety of drugs with narrow therapeutic windows to ensure that they do not cause severe toxicity at therapeutic doses.
  • Therapeutic Agents with Novel Mechanisms of Action: Determine the safety of drugs with unique mechanisms of action to identify potential unexpected toxicities.

This assay is a crucial step in the preclinical evaluation of pharmaceuticals and can help identify potential safety concerns early in the drug development process. It provides critical data to inform further testing and regulatory decision-making.

All protocols are for Research Use Only. Not for use in diagnostic procedures.