Drug Development Process and Screening
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Questions and Answers

What is biological screening of drug activities?

It is the process by which a compound is proven to be either pharmacologically active or inert.

Drug screening can only identify pharmacologically active compounds.

False

What is one reason why we haven't cured diseases like cancer or Alzheimer's yet?

The complexity of the diseases and the need for specific targeting in treatment.

What is the first step in the pre-clinical drug development process?

<p>Identify a Drug Target</p> Signup and view all the answers

What does 'in vitro' mean?

<p>In glass</p> Signup and view all the answers

Match the following assay techniques with their purpose:

<p>PCR = Measure DNA Gel electrophoresis = Separate DNA fragments ELISA = Measure protein levels Western Blot = Analyze protein expression</p> Signup and view all the answers

How are cell lines derived?

<p>Cells are removed from the tissue and disaggregated by enzymatic or mechanical means.</p> Signup and view all the answers

What is the focus of molecular assays?

<p>Measuring various subcellular targets</p> Signup and view all the answers

Which statement is true regarding antimicrobial treatments?

<p>They will become less effective over time.</p> Signup and view all the answers

What does 'in vivo' refer to?

<p>In a living body</p> Signup and view all the answers

How are cell lines typically derived?

<p>From tissue through mechanical disaggregation</p> Signup and view all the answers

Which of the following is NOT a type of molecular assay?

<p>MRI</p> Signup and view all the answers

Which of these gaps pertains to pharmaceutical delivery mechanisms?

<p>Gap 2</p> Signup and view all the answers

What does 'ex vivo' mean in the context of biological studies?

<p>Outside of a living body</p> Signup and view all the answers

Which type of gap means that a treatment does not exist or is insufficiently effective?

<p>Gap 3</p> Signup and view all the answers

What is one of the essential components of cell culture media?

<p>Fetal bovine serum</p> Signup and view all the answers

What characterizes anchorage-dependent cells in culture?

<p>They require a solid or semi-solid substrate to grow.</p> Signup and view all the answers

What defines the process of senescence in cell cultures?

<p>The genetically programmed limit to cell division.</p> Signup and view all the answers

Which of the following tools is commonly used for culturing cells?

<p>Sterile plastic tissue culture flasks</p> Signup and view all the answers

What is the main purpose of biological screening of drug activities?

<p>To establish whether a compound is pharmacologically active or inert</p> Signup and view all the answers

What environmental condition is crucial for maintaining cell culture?

<p>Regulated pH, tonicity, and temperature</p> Signup and view all the answers

Which step occurs immediately after identifying a drug target in the pre-clinical drug development process?

<p>Develop a Bioassay</p> Signup and view all the answers

How do immortal cell lines differ from finite cell lines?

<p>Finite cells can only divide for a limited number of times.</p> Signup and view all the answers

What challenge does the emerging problem of antibiotic resistance present?

<p>It complicates the process of developing new antibiotics</p> Signup and view all the answers

What is the role of antibiotics in cell culture media?

<p>To prevent bacterial infections.</p> Signup and view all the answers

Which of the following is the last step in the pre-clinical drug development process?

<p>File for approval as an Investigational New Drug (IND)</p> Signup and view all the answers

Which of the following is NOT a component typically found in culture medium?

<p>Heavy metals</p> Signup and view all the answers

Why might new drug classes be needed according to the content?

<p>To treat diseases currently deemed untreatable</p> Signup and view all the answers

What is the purpose of establishing effective and toxic doses during pre-clinical studies?

<p>To ensure the drug is safe and effective for human use</p> Signup and view all the answers

What aspect of the drug development process does regulatory approval focus on?

<p>Safety and efficacy of the drug</p> Signup and view all the answers

What is the significance of pharmacovigilance in the drug development process?

<p>To monitor the effects of medicines after they are on the market</p> Signup and view all the answers

What is the primary aim of using controls and reference standards in experiments?

<p>To reduce biological variability</p> Signup and view all the answers

Which of the following best describes the process of randomization in research studies?

<p>Subjects are randomly assigned to treatment groups based solely on chance</p> Signup and view all the answers

What is a key benefit of blinding in experimental studies?

<p>It minimizes observation bias</p> Signup and view all the answers

In in vitro studies, why is it important to use the same cell line from the same species?

<p>To ensure consistency and comparability of results</p> Signup and view all the answers

Which factor is essential for replication in both in vitro and in vivo studies?

<p>Repeating the experiment at least three times</p> Signup and view all the answers

How does randomization contribute to minimizing bias in research?

<p>By equally distributing characteristics among groups</p> Signup and view all the answers

What is the minimum number of animals recommended per group in in vivo studies to reduce variability?

<p>6-30 animals</p> Signup and view all the answers

Which type of bias is specifically reduced by blinding in experiments?

<p>Observation bias</p> Signup and view all the answers

What distinguishes continuous cell lines from finite cell lines?

<p>Continuous cell lines have a high growth rate.</p> Signup and view all the answers

Which of the following best describes spontaneous animal models?

<p>They naturally occur and correspond to human diseases.</p> Signup and view all the answers

Which characteristic is associated with finite cell lines?

<p>They have a limited number of cell generations.</p> Signup and view all the answers

What is the primary purpose of ex vivo assays?

<p>To analyze the effects of compounds on isolated organs or tissues.</p> Signup and view all the answers

What is the significance of nude mice in the context of animal models?

<p>They have a spontaneous genetic mutation leading to an altered immune response.</p> Signup and view all the answers

Which of the following statements about in vivo assays is true?

<p>They aim to study biological responses within a living organism.</p> Signup and view all the answers

What doubling time range is typical for continuous cell lines?

<p>12-24 hours</p> Signup and view all the answers

Which characteristic is NOT true for finite cell lines?

<p>They can grow indefinitely.</p> Signup and view all the answers

Study Notes

Biological Screening of Drug Activities

  • Biological screening is the process of determining whether a compound is pharmacologically active or inert.
  • It is used to identify potential pharmacological activities of a tested compound (qualitative analysis).

Drug Development Process

  • The drug development process aims to discover and develop new drugs to treat diseases.
  • It addresses challenges such as finding cures for complex diseases like cancer and Alzheimer's, and combating antibiotic resistance.

Steps of Pre-Clinical Studies

  • The steps of pre-clinical studies include:
    • Identifying a drug target
    • Developing a bioassay
    • Screening the drug in the assay
    • Establishing effective and toxic doses
    • Filing for approval as an Investigational New Drug (IND)

WHO Priority Medicines and Pharmaceutical Gaps

  • The WHO identifies pharmaceutical gaps, where new medications are urgently needed.
  • These gaps are categorized based on the availability and effectiveness of existing treatments:
    • Gap 1: Treatments exist but will become ineffective (e.g., antimicrobials, influenza pandemic).
    • Gap 2: Treatments exist but their delivery mechanism or formulation is not suitable for the target population (e.g., cardiovascular diseases, cancer, HIV/AIDS, depression).
    • Gap 3: No effective treatments currently exist (e.g., acute stroke, osteoarthritis, Alzheimer's and dementia).

Disease Models

  • Disease models are used to mimic biological systems and assess drug efficacy.
  • Levels of disease modeling include:
    • Molecular Level: Focuses on individual components of the system (e.g., DNA, RNA, proteins).
    • Cellular Level (In Vitro): Studies cellular processes in a controlled environment.
    • Organ/Tissue Level (Ex Vivo): Investigates the function of isolated organs or tissues.
    • Organism Level (In Vivo): Tests drugs in living organisms.

Molecular Assays

  • Molecular assays are used to analyze specific subcellular targets, such as:
    • DNA
    • RNA
    • Gene expression
    • Protein levels
    • Protein-protein interactions
  • Examples of molecular assays include:
    • PCR
    • Gel electrophoresis
    • Western blot
    • Southern blot
    • Sequencing
    • ELISA
  • Molecular assays are divided into proteomics and genomics.

Cellular Assays (In Vitro)

  • Cellular assays involve growing cells in a controlled environment outside their natural organism.
  • Cell cultures allow for the study of cellular processes and drug effects in a controlled setting.

Cell Line Derivation

  • Cell lines are derived by removing cells from tissues and cultivating them in a favorable artificial environment.
  • This process involves disaggregating cells by enzymatic or mechanical means before cultivation.

Biological Screening of Drug Activities

  • Biological Screening is a process used to determine if a compound is pharmacologically active or inert.
  • It is a qualitative analysis that identifies potential pharmacological activity within a tested compound.

Drug Development Process

  • The Drug Development process aims to address unmet medical needs, such as treatments for cancer, Alzheimer's, dementia, diabetes, and antibiotic resistance.
  • This module focuses on the pre-clinical stages of the Drug Development Process.

Steps of Pre-Clinical Studies

  • Pre-clinical studies involve identifying a drug target, developing a bioassay, screening the drug in the assay, establishing effective and toxic doses, and finally filing for approval as an Investigational New Drug (IND).

  • Identify Drug Target: Focuses on pharmacological classes with a high need for new drugs, particularly in areas where existing treatments are becoming ineffective, have inadequate delivery mechanisms, or are absent.

  • WHO Priority Medicine and Pharmaceutical Gaps: The World Health Organization (WHO) identifies three main gaps in drug development:

    • Gap 1: Existing treatments are becoming ineffective, such as antimicrobial resistance and influenza pandemics.
    • Gap 2: Existing treatment delivery mechanisms or formulations are unsuitable for the target population, examples including cardiovascular disease, cancer, HIV/AIDS, and depression.
    • Gap 3: Effective treatments are absent or insufficiently effective, such as acute stroke, osteoarthritis, Alzheimer's, and dementia.

  • Develop a Bioassay: This step focuses on mimicking biological systems using a variety of models:

    • Molecular Level: Analyzing DNA, RNA, gene expression, protein levels, and protein-protein interactions through techniques such as PCR, gel electrophoresis, Western Blot, Southern Blot, sequencing, and ELISA.
    • Cellular Level (In Vitro): Uses cell culture, a technique that involves removing cells from their natural environment and growing them in a controlled artificial environment to maintain viability.
    • Organ/Tissue Level (Ex-Vivo): Involves using isolated organs or tissues from living systems under controlled conditions to study drug effects.
    • Organism Level (In Vivo): Studies the biological effect or response of a drug on a living system, typically using experimental animals. These techniques are primarily conducted on rodents.

  • Cell Culture: A process that involves isolating cells from tissues, disaggregating them through enzymatic or mechanical methods, and then growing them in a controlled environment.

  • Culture Conditions: Involve creating an environment that supports cell growth, typically in a sterile vessel containing culture media.

    • Culture Media: A solution rich in essential nutrients like amino acids, carbohydrates, vitamins, minerals, growth factors, hormones, gases (O2, CO2), and a regulated physico-chemical environment for optimal growth (pH, tonicity, and temperature).
    • Key Components: Culture media is typically supplemented with fetal bovine serum (FBS) for its nutrient content and antibiotics (penicillin, streptomycin) to prevent infection.
    • Culture Vessels: Sterile, disposable plastic flasks are often used, treated to provide a hydrophilic surface for cell attachment.

  • Cell Types: Cells can be categorized as either finite or continuous cell lines

    • Finite Cell Lines: Have a limited lifespan and divide only a certain number of times before senescence. They are also known as normal cells.
    • Continuous Cell Lines: Become immortal through a process called transformation, allowing them to divide indefinitely. Examples include cancer cells.

Animal Models

  • Animal models are used to study drug effects in a living system.
  • Types of Animal Models:
    • Spontaneous: Natural mutations or genetic variances mimic human conditions.
    • Induced: Conditions are experimentally induced in the animal to mimic a human disease.
    • Genetically Modified: Experimental genetic modifications are used to create specific animal models for research.

Selection of Animals

  • When conducting in vitro studies, the cell lines used should be extracted from the same species of animals.
  • In vivo studies should utilize animals of the same species, age, weight, and sex for consistent results.

Replication

  • To reduce variability and error, drug effects should be replicated multiple times, collecting mean values for analysis.
  • Typically: 3 to 6 wells per treatment for in vitro studies and 6-30 animals per group for in vivo studies.
  • The entire experiment should be repeated at least 3 times to ensure consistency.

Use of Controls and Reference Standards

  • Purpose: Controls and reference standards are used to reduce biological variability caused by changes in procedure, time, or conditions. They provide a baseline for comparison.
  • Role: International standards are used to compare drug activity across different studies, as their activity remains constant.

Bias Counteraction

  • Research Bias: The influence of the scientists on the research outcomes to portray a desired result.

  • Strategies: The use of randomization and blinding can minimize research bias.

  • Randomization: A process of assigning participants to treatment groups randomly, ensuring equal distribution of characteristics across groups.

  • Blinding: A method of hiding information from participants and/or researchers to minimize bias.

    • Randomization reduces selection bias.
    • Blinding reduces observation bias.

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Biological Screening of Drug Activities Lecture 2

Description

Dive into the essential processes of drug development, including biological screening and pre-clinical studies. Learn how these components play a crucial role in identifying new medications for various diseases, as well as understanding the pharmaceutical gaps identified by the WHO.

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