40 Questions
What is the primary mechanism of absorption for subcutaneous injections?
Simple diffusion
Which route of administration is used to bypass the blood-brain barrier?
Intrathecal/intraventricular
What is the primary advantage of subcutaneous injection over intravenous injection?
Minimized risk of hemolysis or thrombosis
What type of preparation is used for intramuscular injections that are absorbed slowly?
Specialized depot preparation
What is the primary consideration when choosing a subcutaneous injection route?
The drug's potential for tissue irritation
Which route of administration is used to achieve systemic effects by application of drugs to the skin?
Transdermal
What is the primary advantage of rectal administration?
Bypassing the portal circulation
What type of effect is desired when using a topical route of administration?
Local effect
What factor determines the fraction of molecules charged or uncharged for weak bases and weak acids?
The pH of the medium
According to Fick's law, which of the following would increase the rate of drug absorption into the blood?
Increasing the concentration gradient
What is the main difference between aqueous diffusion and lipid diffusion?
One occurs through aqueous pores, while the other occurs through lipid bilayer cell membranes
What equation can be used to predict the fraction of molecules in the ionized state?
Henderson-Hasselbalch equation
What is the result of protonation on weak bases?
They become more hydrophilic and more water soluble
What is the result of protonation on weak acids?
They become more lipophilic and less water soluble
Which of the following organs has a larger absorbing surface area, resulting in faster drug absorption?
Small intestine
What determines the rate of movement of molecules across a barrier, according to Fick's law?
The concentration gradient, permeability coefficient, and the area and thickness of the barrier membrane
What is the name of the technique used to produce monoclonal antibodies?
Hybridoma
Which of the following is an example of a natural drug?
Gonadotrophins
What is the primary goal of preclinical tests in drug development?
To assess the acute toxicity of the drug
Which of the following is an example of a chemical name of a drug?
Acetyl-pamino-phenol
What is the name of the approach to drug discovery that involves modifying the structure of known drugs to make them more potent or less toxic?
Modification of structure of known drugs
Which of the following is an example of a mineral used as a drug?
Iron
What is the term for the name given to a drug by the manufacturer?
Trade name
Which of the following is an approach to drug discovery that involves searching for new uses of drugs already in use?
Discovery of new uses of drugs already in use
What is the primary focus of pharmacokinetics?
The study of what the body does to the drug
What is the purpose of pharmacokinetic principles in rational dosing?
To quantify the absorption, distribution, and elimination of a drug
What is the primary mechanism of drug transport across the cell membrane?
Carrier-mediated transport
What is the main purpose of permeation in pharmacokinetics?
To facilitate the movement of drug molecules into and within the biologic environment
What is the primary route of drug administration that affects pharmacokinetics?
Oral
What is the primary type of diffusion that occurs through the watery extracellular and intracellular spaces?
Aqueous diffusion
What is the primary function of the small water-filled pores in the membranes of most capillaries?
To permit the aqueous diffusion of molecules up to the size of small proteins
What is the primary purpose of pharmacodynamics?
To study the biological effects of a drug on the body
What is the primary focus of pre-clinical tests in pharmacological studies?
To assess the toxicity of a new drug in vitro and in vivo
Which of the following is NOT a type of toxicity study?
Pharmacodynamic effects
What is the primary goal of Phase 1 clinical trials?
To assess the safety and tolerability of a new drug in humans
Which phase of clinical trials involves post-marketing surveillance of a newly approved drug?
Phase 4
What is the purpose of a double-blind study in pharmacological research?
To mask the identity of the treatment and the outcome from both the researcher and the patient
What is the term for the study of the effects of a drug on reproduction?
Reproductive toxicity
Which of the following is a type of pharmacokinetic study?
Absorption, metabolism, and excretion
What is the term for the study of the potential of a drug to cause genetic mutations?
Mutagenicity
Study Notes
Sources of Drugs
- Natural drugs: insulin, heparin, gonadotrophins, thyroid extract, and antitoxic sera (e.g., anti-snake venom)
- Microorganisms: penicillin, streptomycin, erythromycin, polymyxin B, bacitracin, chloramphenicol, nystatin, and griseofulvin
- Minerals: iron, calcium, magnesium, liquid paraffin, ferrous sulfate, magnesium sulfate, magnesium trisilicate, and kaolin
- Genetic engineering: human insulin, growth hormone, and monoclonal antibodies
Drug Nomenclature
- Chemical/molecular/scientific name: e.g., acetyl-pamino-phenol (paracetamol)
- International/generic/approved name: e.g., ACE inhibitors (e.g., captopril)
- Brand/trade name: e.g., paracetamol (acetaminophen) with over 30 trade names (e.g., Crocin, Panadol)
Principal Approaches to Drug Discovery
- Synthesis of analogues, agonists, or antagonists of endogenous substances (e.g., hormones)
- Modification of structure of known drugs for more potent or less toxic drugs
- Random screening of novel chemicals for biological activity
- Discovery of new uses of drugs already in use
- Search for drugs from traditional remedies
Scientific Studies of New Drug
- Preclinical tests:
- Acute toxicity
- Pharmacological studies (in vitro, in vivo activity; effective dose)
- Toxicity studies (reproduction, teratogenicity, mutagenicity, and carcinogenicity)
- Evaluation in man:
- Phase 1: Clinical pharmacology test on human volunteers
- Phase 2: Clinical investigation (patient blind study, 50-300 patients)
- Phase 3: Formal therapeutic trials (randomized, controlled, multi-centric, 250-1000 patients)
- Phase 4: Post-marketing surveillance
Pharmacokinetics
- The study of what the body does to the drug (absorption, distribution, metabolism, and excretion)
- Principles:
- Absorption: drug passage across the cell membrane and route of administration
- Distribution: drug movement within the body
- Metabolism: drug transformation into inactive or active forms
- Excretion: drug elimination from the body
- Permeation: movement of drug molecules into and within the biologic environment
- Aqueous diffusion: movement of molecules through watery extracellular and intracellular spaces
- Lipid diffusion: passive movement of molecules through lipid bilayer cell membranes and other lipid barriers
- Fick's Law of Diffusion: predicts the rate of movement of molecules across a barrier
Route of Administration
- Oral: most common route, but affected by pH, food, and gastrointestinal factors
- Parenteral: injection into the body, bypassing the gastrointestinal tract
- Intravenous: rapid absorption, but high risk of adverse reactions
- Intramuscular: absorption via simple diffusion, with slower absorption rates
- Subcutaneous: absorption via simple diffusion, slower than IV route
- Topical: local effect of the drug, used for skin, eye, ear, nose, vaginal, and urethral applications
- Transdermal: systemic effects achieved by application of drugs to the skin, usually via a transdermal patch
- Rectal: 50% of the drainage of the rectal region bypasses the portal circulation, preventing destruction of the drug in the GI environment
This quiz covers the basics of pharmacokinetics and pharmacodynamics, including the principles of absorption, distribution, metabolism, and elimination of drugs and their effects on the body.
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