Pre-Clinical Studies Flashcards
Involve experiments conducted on living organisms, typically animals, to observe the effects of a drug in a whole-body system.
In Vivo Testing
Involves experiments performed on isolated cells, tissues, or organs outside of a living organism, providing a simplified model for studying drug effects.
In Vitro Testing
INTRODUCTION TO IN VIVO DRUG SAFETY TESTING
In vivo studies provide valuable insights into how a drug interacts with a living organism, including its absorption, distribution, metabolism, and excretion.
Understanding Drug Behavior
INTRODUCTION TO IN VIVO DRUG SAFETY TESTING
These studies assess the potential for a drug to cause adverse effects, such as organ damage, reproductive issues, or carcinogenicity.
Evaluating Toxicity
INTRODUCTION TO IN VIVO DRUG SAFETY TESTING
The data from in vivo studies helps researchers design safer and more effective clinical trials in human participants.
Informing Clinical Trials
REGULATORY REQUIREMENTS FOR IN VIVO STUDIES
Drug safety evaluations must comply with guidelines set by organizations
Global Regulatory Bodies
REGULATORY REQUIREMENTS FOR IN VIVO STUDIES
Global regulatory bodies:
- FDA
- EMA
- OECD
- Food and Drug Administration
- European Medicines Agency
- Organisation for Economic Co-operation and Development
REGULATORY REQUIREMENTS FOR IN VIVO STUDIES
In vivo studies must adhere to strict animal welfare regulations and protocols to minimize suffering.
Ethical Considerations
REGULATORY REQUIREMENTS FOR IN VIVO STUDIES
Regulatory agencies provide standardized study designs and methods to ensure consistent, high-quality data.
Standardized Protocols
REGULATORY REQUIREMENT: PHILIPPINE SETTING
The primary agency responsible for regulating animal use in drug development in the Philippines is the ___ , which is under the Department of Agriculture (DA).
Bureau of Animal Industry (BAI); Department of Agriculture (DA)
The BAI oversees and implements the ___ , which provides the legal framework for the humane treatment of animals used in research and development.
Animal Welfare Act of 1998 (Republic Act No. 8485)
What BAI does: (4)
- Issue permits
- Monitor and Inspect
- Investigate Complaints
- Promote ethical practices
In addition to the BAI, other agencies that may be involved in regulating animal use in drug development in the Philippines include: (3)
- Department of Health (DOH)
- Department of Science and Technology - Philippine Council for Health Research and Development (DOST - PCHRD)
- Institutional Animal Care and Use Committees (IACUCs)
The ___ may be involved in setting standards for the use of animals in biomedical research.
Department of Health (DOH)
The ___ may provide guidelines and ethical review for research involving animals.
DOST - Philippine Council for Health Research and Development (PCHRD)
Are established within research institutions (university) to review and approve animal use protocols.
Institutional Animal Care and Use Committees (IACUCs)
They play a crucial role in the development and testing of new drugs. By studying how drugs impact different species, researchers can gain valuable insights into safety, efficacy, and potential side effects before human trials.
Animal models
Rodent models (3)
- Mice
- Rats
- Guinea Pigs
Non-Rodent models (4)
- Primates
- Pigs
- Dogs
- Rabbits
Rodents that are small size, short lifespan, easy to breed and handle.
Mice
Rodents that are larger size, longer lifespan, more robust physiology.
Rats
Rodents that are similar to humans in terms of vitamin C requirements.
Guinea pigs
Non-rodents that are closest to humans in terms of physiology and genetics, valuable for studying diseases like HIV and Alzheimer’s.
Primates
Non-rodents that are used for studying organ transplantation and cardiovascular research, similar size and anatomy to humans.
Pigs
Non-rodents that are large animal models for studying cancer, diabetes, and cardiovascular diseases, long lifespan allows for chronic studies.
Dogs
Non-rodents that are used for studying reproductive and developmental toxicology, convenient size and relatively low cost.
Rabbits
Are widely used in drug research due to their physiological similarities to humans. Understanding different ___ strains is crucial for selecting the most appropriate model for specific research questions. Their names are from research centers
Rats
Types of Rats: (5)
- Wistar Rats
- Sprague Dawley Rats
- Long-Evans Rats
- Spontaneously Hypertensive Rats (SHR)
- Zucker Diabetic Fatty Rats (ZDFR)
An albino strain characterized by their white fur and pink eyes.
Wistar rats
They are known for their rapid growth and adaptability, making them suitable for various research purposes.
Wistar rats
Applications in Drug Studies
Wistar rats are commonly used in ___ , ___ , and ___ .
toxicology,
cancer research,
behavioral studies
Their predictable responses to drug treatments make them valuable models for evaluating drug efficacy and safety.
Wistar rats
Wistar physical characteristics: (3)
- Long ears
- Tail length shorter than body length
- Wider head
Are a popular strain known for their docile nature, rapid growth rate, and high reproductive rate.
Sprague Dawley rats
These qualities make Sprague Dawley rats suitable for various studies, including ___ , ___ , and ___ .
toxicology,
pharmacology,
safety testing
Kinds of rats with consistent physiology which allows for reliable data collection and interpretation.
Sprague Dawley rats
Researchers often use Sprague Dawley rats for general ___ and to evaluate ___ .
toxicity testing,
drug efficacy
Are known for their hooded coat pattern, featuring a darker, pigmented area on the head and shoulders.
Long-Evan rats
This strain is also recognized for its relatively larger size compared to other commonly used rat strains.
Long-Evan rats
Long-Evans rats are cross between a ___ and a ___ .
Female albino,
Wild male (Rattus norvegicus)
Long-Evans rats are often used in behavioral research due to their well-documented behavioral patterns and responses. They are also valuable models for studying ___ and ___ .
neurological disorders,
drug-induced behavioral changes
Are genetically predisposed to hypertension, characterized by elevated blood pressure.
Spontaneously Hypertensive Rats (SHR)
Spontaneously Hypertensive rats are commonly used in research on cardiovascular diseases, including ___ , ___ , and ___ .
stroke,
heart failure,
hypertension
Spontaneously Hypertensive rats are valuable models for evaluating new drugs for ___ and other ___ . Their sensitivity to *** makes them particularly useful for testing the efficacy of antihypertensive drugs.
hypertension,
cardiovascular disorders
Are genetically predisposed to obesity and type 2 diabetes.
Zucker Diabetic Fatty (ZDF)
These rats are characterized by their distinctive white fur and tendency to develop insulin resistance.
Zucker Diabetic Fatty (ZDF)
ZDF rats are valuable models for studying ___ , ___ , and related ___ . Researchers utilize ZDF rats to evaluate the efficacy and safety of new drugs for managing ** and **.
diabetes,
obesity,
metabolic disorders
Considerations in rat selection: (6)
- Genetic background
- Age
- Sex
- Health status
- Environmental factors
- Ethical consideration
Types of In Vivo Pre-Clinical Studies: (9)
- Acute Toxicity Studies
- Subchronic Toxicity Studies
- Chronic Toxicity Studies
- Reproductive Toxicity Studies
- Genetic Toxicity Studies
- Pharmacokinetic Studies
- Efficacy Studies
- Safety Pharmacology Studies
- Immunogenicity Studies
ACUTE TOXICITY STUDIES
A single, high dose of the drug is given to assess immediate, short-term effects.
Dose Administration
ACUTE TOXICITY STUDIES
Animals are closely monitored for signs of toxicity, such as changes in behavior, physiology, and mortality.
Observation Period
ACUTE TOXICITY STUDIES
Detailed examination of organ tissues to identify any damage or abnormalities.
Pathology Analysis
SUBCHRONIC TOXICITY STUDIES
The drug is administered for a longer period, typically 28-90 days, to assess medium-term effects.
Exposure Duration
SUBCHRONIC TOXICITY STUDIES
Multiple dose levels are tested to determine the threshold for toxicity and establish safe dosing ranges.
Dose Levels
SUBCHRONIC TOXICITY STUDIES
In-depth analysis of clinical chemistry, hematology, and histopathology to identify potential organ-specific toxicity.
Comprehensive Evaluation
CHRONIC TOXICITY STUDIES
The drug is administered for an extended period, typically 6 months to 2 years, to assess long-term effects.
Long-Term Exposure
CHRONIC TOXICITY STUDIES
Gradually increasing the dose over time to identify the maximum tolerable dose and potential cumulative toxicity.
Dose Escalation
CHRONIC TOXICITY STUDIES
In-depth evaluation of organ function, histopathology, and any other adverse effects that may develop.
Comprehensive Assessment
REPRODUCTIVE TOXICITY STUDIES
Assessing the drug’s impact on mating, conception, and sperm/egg production.
Fertility
REPRODUCTIVE TOXICITY STUDIES
Evaluating the drug’s effects on the developing embryo and fetus during pregnancy.
Embryonic/Fetal Development
REPRODUCTIVE TOXICITY STUDIES
Monitoring the growth and development of offspring exposed to the drug in utero.
Postnatal Development
REPRODUCTION TOXICITY STUDIES
Examining the drug’s effects over multiple generations to identify any heritable changes.
Multi-Generation Studies
GENETIC TOXICITY STUDIES
Assessing the drug’s potential to cause permanent changes in the genetic material of cells.
GENETIC TOXICITY STUDIES
Evaluating the drug’s ability to induce chromosomal breaks, rearrangements, or other abnormalities.
Clastogenicity
GENETIC TOXICITY STUDIES
Analyzing the drug’s impact on the integrity and repair of genetic material.
DNA Damage
PHARMACOKINETIC STUDIES (4)
- Absorption
- Distribution
- Metabolism
- Excretion
EFFICACY STUDIES
Demonstrates the drug’s ability to achieve its intended effect.
Proof-of-Concept
EFFICACY STUDIES
Determines the optimal dosage for efficacy.
Dose-Response
EFFICACY STUDIES
Identifies the range of doses that provide benefit without excessive toxicity.
Therapeutic Window
EFFICACY STUDIES
Assesses the drug’s effectiveness over extended periods.
Long-Term Effects
SAFETY PHARMACOLOGY STUDIES
Assess effects on heart rate, blood pressure, and rhythm.
Cardiovascular
SAFETY PHARMACOLOGY STUDIES
Evaluate impact on breathing rate, depth, and lung function.
Respiratory
SAFETY PHARMACOLOGY STUDIES
SAFETY PHARMACOLOGY STUDIES
Examine effects on behavior, cognition, and motor function.
Central Nervous System
SAFETY PHARMACOLOGY STUDIES
Assess impact on digestion, absorption, and bowel movements.
Gastrointestinal
IMMUNOGENICITY STUDIES (2)
- Immunomodulation
- Immunosuppression
IMMUNOGENICITY STUDIES
Measure the production of antibodies against the drug or its components.
Antibody Response
IMMUNOGENICITY STUDIES
Evaluate the activation of immune cells like T cells, which can directly attack cells expressing the drug.
Cell-Mediating Immunity
IMMUNOGENICITY STUDIES
Analyze the levels of various immune signaling molecules (cytokines) in blood or tissues.
Cytokine Profile
IMMUNOGENICITY STUDIES
Examine tissue samples under a microscope to assess the presence of immune cells and inflammation.
Histopathology
DATA ANALYSIS AND INTERPRETATION OF IN VIVO STUDY RESULTS
Applying rigorous statistical methods to identify significant drug-related effects and trends.
Statistical Analysis
DATA ANALYSIS AND INTERPRETATION OF IN VIVO STUDY RESULTS
Evaluating how changes in dose affect the magnitude and incidence of observed effects.
Dose-Response Relationships
DATA ANALYSIS AND INTERPRETATION OF IN VIVO STUDY RESULTS
Carefully translating animal data to predict potential safety and efficacy in human clinical trials.
Extrapolation to Humans
Ethical Considerations on Animal Models in Drug Development
The 3 R’s
- Replacement
- Reduction
- Refinement
Seek to replace animal models with alternative methods such as in vitro or in silico approaches whenever possible.
Replacement
Design studies to minimize the number of animals used while maintaining scientific validity.
Reduction
Continually improve procedures to enhance animal welfare and minimize pain, distress, and suffering.
Refinement
EVALUATING THE SCIENTIFIC MERIT AND NECESSITY OF ANIMAL STUDIES
Ensure that the study design and methodology is robust and can yield meaningful, reproducible results.
Scientific Validity
EVALUATING THE SCIENTIFIC MERIT AND NECESSITY OF ANIMAL STUDIES
Carefully weigh the potential benefits of the research against the risks and suffering imposed on animals.
Minimizing Harm
EVALUATING THE SCIENTIFIC MERIT AND NECESSITY OF ANIMAL STUDIES
Continually seek and implement alternative methods that can replace animal models when feasible.
Alternative Exploration
EVALUATING THE SCIENTIFIC MERIT AND NECESSITY OF ANIMAL STUDIES
Require rigorous ethical review and approval before conducting any animal research studies.
Ethical Review
MINIMIZING ANIMAL SUFFERING
Utilize appropriate anesthetic agents to eliminate pain and distress during procedures.
Anesthesia
MINIMIZING ANIMAL SUFFERING
Provide analgesics to manage pain and discomfort before, during, and after experiments.
Analgesia
MINIMIZING ANIMAL SUFFERING
Ensure humane and painless methods of euthanasia when animals must be sacrificed.
Euthanasia
ENSURING PROPER ANIMAL WELFARE
Provide appropriate, spacious, and enriched environments to support the animals’ natural behaviors.
Housing
ENSURING PROPER ANIMAL WELFARE
Ensure that animals receive a balanced and nutritious diet to maintain their health and well-being.
Nutrition
ENSURING PROPER ANIMAL WELFARE
Establish comprehensive veterinary oversight to monitor the animals’ health and address any issues promptly.
Veterinary Care
LIMITATIONS OF IN VIVO STUDIES
Animal welfare is paramount, necessitating strict ethical guidelines and regulatory oversight to minimize animal suffering.
Ethical Considerations
LIMITATIONS OF IN VIVO STUDIES
Results from animal models may not fully translate to humans due to physiological and metabolic variations.
Species Difference
LIMITATIONS OF IN VIVO STUDIES
In vivo studies involve significant financial investments and time to conduct, especially for long-term studies.
High Cost and Time Commitment
LIMITATIONS OF IN VIVO STUDIES
Individual animal responses can vary, influencing the reliability of study results and requiring careful statistical analysis.
Limited Control over Variables
BALANCING SCIENTIFIC PROGRESS AND ETHICAL CONSIDERATIONS
Maintain an open and constructive dialogue between researchers, ethicists, and the public.
Ongoing Dialogue
BALANCING SCIENTIFIC PROGRESS AND ETHICAL CONSIDERATIONS
Continuously strive to enhance animal welfare and seek alternatives to reduce reliance on animal models.
Continual Improvement
BALANCING SCIENTIFIC PROGRESS AND ETHICAL CONSIDERATIONS
Ensure that animal research is conducted with the highest ethical standards and scientific rigor.
Responsible Research
Evaluating the safety and efficacy of new drug compounds is a critical step in the drug development process. In vitro testing using cell-based models and advanced organ-on-a-chip systems provides an essential foundation for understanding a drug’s potential toxicity before further clinical trials.
Drug Safety Evaluation In Vitro
ADVANTAGES OF IN VITRO STUDIES
In vitro studies provide a fast and efficient way to screen potential drug candidates, enabling quicker identification of promising leads.
Rapid Screening
ADVANTAGES OF IN VITRO STUDIES
In vitro studies are generally less expensive to conduct than in vivo studies, reducing overall drug development costs.
Cost0Effectiveness
ADVANTAGES OF IN VITRO STUDIES
In vitro studies allow for precise control of variables, minimizing external factors that can influence experimental outcomes.
Controlled Environment
ADVANTAGES OF IN VITRO STUDIES
In vitro studies do not involve living organisms, eliminating ethical concerns associated with animal welfare.
Ethical Considerations
CELL-BASED ASSAYS
Choosing the appropriate cell line is crucial, as it should be representative of the target tissue or disease state.
Cell Line Selection
Types of In Vitro Drug Studies: (6)
- Cell-Based Assays
- Genotoxicity and Mutagenicity Testing
- Receptor Binding Assay
- Biochemical/Enzyme Activity Assays
- Permeability Studies
- Metabolic Stability Studies
CELL-BASED ASSAYS
Cell-based assays can measure various cellular responses, such as proliferation, differentiation, or signaling pathway activation.
Functional Readouts
CELL-BASED ASSAYS
These assays can assess the cytotoxic effects of drug candidates on cells, helping identify potential safety concerns.
Toxicity Evaluation
GENOTOXICITY AND MUTAGENICITY TESTING
Detecting mutagenic potential using bacterial reverse mutation assays.
Ames Test
GENOTOXICITY AND MUTAGENICITY TESTING
Measuring DNA strand breaks and alkaline-labile sites in individual cells.
Comet Assay
RECEPTOR BINDING ASSAYS
These assays determine the selectivity of a drug candidate for its intended receptor target, versus off-target receptors.
Receptor Specificity
GENOTOXICITY AND MUTAGENICITY TESTING
Evaluating chromosomal damage and aneuploidy in mammalian cells.
Micronucleus Assay
RECEPTOR BINDING ASSAYS
Receptor binding assays quantify the strength of the interaction between a drug candidate and its target receptor.
Binding Affinity
RECEPTOR BINDING ASSAYS
Some receptor binding assays also measure the ability of a drug candidate to activate or inhibit the receptor’s downstream signaling pathways.
Functional Activation
BIOCHEMICAL/ENZYME ACTIVITY ASSAYS
These assays determine the ability of a drug candidate to inhibit the activity of a target enzyme, which can be a potential mechanism of action.
Enzyme Inhibition
BIOCHEMICAL/ENZYME ACTIVITY ASSAYS
Enzyme activity assays can provide information on the kinetic parameters of an enzyme-drug interaction, such as the rate of catalysis or inhibition.
Enzyme Kinetics
PERMEABILITY STUDIES
Measures the ability of a drug candidate to passively diffuse across cell membranes, which is crucial for oral bioavailability.
Passive DIffussion
BIOCHEMICAL/ENZYME ACTIVITY ASSAYS
Enzyme activity assays are well-suited for high-throughput screening of large chemical libraries to identify potential drug candidates.
High-Throughput Screening
PERMEABILITY STUDIES
Assesses the likelihood of a drug candidate to cross the blood-brain barrier and reach the central nervous system.
Blood-Brain Barrier
PERMEABILITY STUDIES
Evaluates the potential for a drug candidate to be a substrate or inhibitor of membrane transporter proteins.
Active Transport
METABOLIC STUDIES
These studies identify the major metabolic pathways and enzymes involved in the biotransformation of a drug candidate.
Metabolism Pathways
METABOLIC STUDIES
Metabolic stability assays can provide a comprehensive understanding of the drug’s metabolic fate and potential metabolite-mediated effects.
Metabolite Profiling
METABOLIC STUDIES
The rate of drug metabolism is crucial for determining the appropriate dosing regimen and predicting in vivo pharmacokinetics.
Half-Life Determination
“Animal research and testing has played a part in almost every medical breakthrough of the last century. It has saved hundreds of millions of lives worldwide”
Jean Ryan
