Pharmacology: Scope, History & Applications

• Objectives of the course are to list the sources of drugs, describe routes of drug administration and how these affect drug action onset, and explain ADME factors.

History of Pharmacology

• Pharmacology comes the Greek word pharmakon, meaning "poison" in classic Greek and "drug" in modern Greek.
• Pharmacology is part of biology and medicine, studying drug action.
• It studies how drugs interact with living animals, focusing on the mechanisms, therapeutic uses, and other applications of drugs.
• Pharmacology looks at the relations between living things and chemicals, with attention to normal or abnormal biochemistry and includes drug composition, synthesis, and design.
• Other factors in pharmacology are molecular and cellular communication, molecular diagnostics, interactions, toxicology, chemical biology, and therapy.
• Egyptians are known to have used herbal treatments from as early as around 1550 BCE, documented in texts like the Ebers Papyrus.
• The Ebers papyrus includes remedies for diagnosis and therapy of varied diseases, surgical procedures, recipes, magic spells, and incantations.
• Ancient Chinese medicine features texts like the "Huangdi Neijing" from the Han dynasty (206 BCE - 220 CE), advocating for system balance and listed herbs.
• Hippocrates (460-370 BCE) and Galen (129-216 CE) created basic medical approaches.

The Medieval Era and the Islamic Golden Age

• The rise of Islam expanded pharmaceutical study during the Middle Ages.
• Avicenna (Ibn Sina) and Al-Razi (Rhazes) greatly contributed to this field.
• Avicenna's "The Canon of Medicine," from the 11th century, is considered an medical text covering range of medical information, like drug properties and uses.
• Alchemy, originally about changing substances, helped create chemistry and isolate active plant compounds, forming modern pharmaceutical practices.

The Renaissance and the Birth of Modern Pharmacology

• The Renaissance restarted attention to empirical study and science, which changed pharmacology, also known as scientific inquiry.
• Andreas Vesalius (1514-1564) improved anatomical knowledge.
• Paracelsus (1493-1541) changed pharmacology by emphasizing the relevance of chemical substances and their doses, inspiring toxicology, and is known for saying: "all things are poison, and nothing is without poison, the dose alone makes it so a thing is not a poison."
• The first pharmacopoeias appeared, which was important for medicine preparation, standardization, guidelines and quality, including "Pharmacopoeia Londinensis" of 1618.

The 19th Century: A Period of Transformation

• Advances in chemistry marked a change in pharmacology during the 19th centuriy, with a deeper of the human body:
• Friedrich Sertürner isolated morphine from opium in 1804, which was the first active ingredient from a plant.
• Induction-based methods were created for synthesizing new drugs.
• John Stith Pemberton created Coca-Cola (originally a medicinal tonic) utilizing compounds, which showed growing ties between chemistry and pharmacology.
• The germ theory of disease, crafted by Louis Pasteur and Robert Koch, helped to refine the development of antibiotics in the early 20th century

The Era of Modern Pharmacology

• In 1928, Alexander Fleming's discovery of penicillin changed medicine and created the era of antibiotics.
• The development of many synthetic drugs expanded therapeutic choices exponentially.
• Drug safety and efficiency became important, while technology advanced.
• The Thalidomide tragedy in the 1960s caused birth defects, thus led to stricter guidelines and drug testing/approvals.
• Organizations such as the U.S. Food and Drug Administration were founded due to the increase of importance on safety/efficacy in drug development.
• Innovations in the late 20th-early 21st centuries include biotechnology and pharmacogenomics, which modify drug therapy by genetic makeup (personalized medicine), improving outcomes/reducing drug reactions.

Relationship of Pharmacology to other Pharmaceutical and clinical subjects

• Pharmaceutical science is related to medicinal chemistry, pharmaceutics, and pharmacokinetics, where pharmacology serves as the base for these areas.

Medicinal Chemistry

• Medicinal chemistry combines chemistry and pharmacology for new pharmaceutical design/development.
• Knowledge of pharmacodynamics (drug effects) and pharmacokinetics (drug absorption, distribution, metabolism, excretion) is crucial for medicinal chemists.
• Insights for pharmacology update molecule design that maximizes effect, while minimizing negative affects.

Pharmaceutics

• Pharmaceutics involves the formulation, manufacturing, and delivery of pharmaceutical goods.
• Pharmacology knowledge is essential in creating medications that improve bioavailability, ensure optimal release, and maximize patient compliance.
• Understanding drug action could lead experts to work around solubility issues, when building drug systems like transdermal patches

Pharmacokinetics

• Pharmacokinetics helps determine how the body affects drugs and is linked to pharmacology.
• Pharmacologists and pharmacokineticists collaborate to comprehend variables influencing drug metabolism/clearance.
• This helps formulate dosage regimens to achieve therapeutic drug levels, while avoiding toxicity.

Clinical Pharmacology

• Focuses on using pharmacological standards for patient care.
• Clinical pharmacologists ensure drug therapy is tailored for unique needs, genetic variability, comorbidities, and medications.

Therapeutics

• Therapeutics is the use of drugs for treating diseases.
• Pharmacology gives factual evidence for drug guidelines, educating doctors of affects, implications and communications.
• This offers the help of risk assessments, so that medical facilities can follow effective patient care.

Pharmacovigilance

• Pharmacovigilance is concerned with safety/efficacy of medicines once approved, which is related to Pharmacology.
• Understanding adverse drug reactions needs a pharmacological perspective (knowledge of mechanisms, drug specificities, that may contribute to unexpected responses.
• Effective pharmacovigilance depends on pharmacological ideas to improve drug safety and marketing surveillance.

Pharmacology and Interdisciplinary Collaboration

• Complexity of medicine needs healthcare providers working together.
• Pharmacology brings together fields like nursing, public health, and biostatistics for shared goals.

Nursing

• Pharmacology helps in nursing, where they're an important part of giving drugs and educating the patients
• A strong background in pharmacological prepares nurse to know regimens, see implications, patients needs.

Public Health

• Public health utilizes pharmacology to help implement population vaccination programs, antimicrobial stewardship, and drug distribution.

Biostatistics

• Biostatistics helps examine clinical trial data and drug efficacy/safety.
• Pharmacologists collaborate with biostatisticians and interpret data from studies, helping in evidence-based drug policies.

Sources of Drugs

• Sources of Drugs can come from plants, animals, and minerals. Historically, drugs derived from nature, with current processes isolating active ingredients from natural sources.

Drugs of Plant Origin

• Plants source of medicinal components. containing alkaloids, terpenoids, flavonoids, and glycosides.
• Morphine is derived from the opium poppy, and is is used for severe pain relief.
• Quinine comes from cinchona tree bark; and is used to treat malaria.
• Aspirin is derived from willow bark and is used for non-steroidal anti-inflammatory.

Drugs of Animal Origin

• Pharmaceutical compounds are obtained from animals (hormones, enzymes, extracts)
• Insulin is extracted from pig/cow pancreas; and is essential diabetes treatment.
• Heparin is from animal membranes.

Drugs of Mineral Origin

• Drugs are derived from mineral/inorganic compounds for therapy.
• Lithium is naturally occurring and treats bipolar.
• Magnesium sulfate.

Semi-Synthetic Sources

• Semi-synthetic drugs come from natural products and the process of change to enhance their efficacy, side effects.
• Vicodin, a mix of hydrocodone (semi-synthetic opioid) and acetaminophen, relieves moderate to severe pain.
• Aspirins pathway to now being a synthetic.

Synthetic Sources

• Synthetic medicines that are chemically made and are not not from nature, with the goal of purity, dosage, and formulation control.
• Antibiotics such as penicillin.

Biotechnology-Derived Drugs

• Biotechnology helps made drugs using living beings or DNA.
• Monoclonal Antibodies are used in cancer treatments. vaccines (e.g., the Pfizer-BioNTech and Moderna COVID-19 vaccines) by use of technique.

Other Emerging Sources

• Marine organisms have unique bioactive properties that can benefit drug discovery.
• Ziconotide is derived from the venom of cone snails for treating chronic pain.

Endophytes

• A fungi/bacteria that lives in plants and can produce compounds to benefit applications.
• Taxol comes from the Pacific yew tree.

Routes of Drug Administration

• The route of drug administration is the process of how a product is put into the body for therapeutic outcomes.
• The route is important, for it impacts absorption, distribution, metabolism, excretion (ADME).

Oral Route

• Drugs taken orally and absorbed through the gastrointestinal tract, for, tablets, elixirs, capsules and are non-convenient and not costing to much.
• Food, PH and mobility will effect it bioavailability.

Sublingual and Buccal Route

• Drugs are placed on the tongue or cheek for absorption into the bloodstream,
• Nitroglycerin and buprenorphine.
• Rapid absorption and bypass metabolism.

Percutaneous Route

• Routes into the body such as, intravenously and intramuscular, by injections.
• Advantages include rapid actions depending on the IV with control over drug concentration, and suitable patients who may have to take medications.

Topical Route

• It's the usage of drugs directly to the akin, cream and patches.
• Localized with minimal absorption and easy to use.

Transdermal Route

• This route delivers medication into the skins by adhesive which provides continuous bypass metabolism for long therapy.
• Some disadvanges are limited molecular size and irritate skins.

Inhalation Route

• Drugs that are to be administered through the respiratory will reach systematic and have local effects. such forms as aerosols and nebulizers.
• The absorption is rapid due to large surface area in the lungs and suitable for respiratory systems.

Intranasal Route

• Drugs that are to be absorbed through the nose, can range from an overdose to diabetes.
• Quick and bypass metabolism.

Rectal Route

• Drugs administered through the rectum.
• Advantages of patients that struggle taking oral medications, and partially bypass metabolism.
• Patient discomfort and variable absorption are a few disadvanges.

Intrathecal and Epidural Route

• Is injecting drugs into the spinal fluid for a central nervous system effect.
• Good treatment for pain, not good for patients with central nervous system.

Drug, Distribution, Elimination, and factors affecting them

• Pharmacokinetics are important the drugs therapeutic effect for adversities, that all include ADME.

Absorption

• Process and how efficient impacts a drugs availability for proportional effect.
• Passive diffusion goes through diffusion, with facilitated using energy and proteins.

Factors Affecting Absorption

• physicochemical properties, route of administrator and gastro factors.

Drug Distribution

• Phases and volume with distribution in between plasmas and tissues affect and the rate acting.
• Drugs move between the blood and the body tissues.
• Vd is how this can calculate.

Factors affecting Distribution

• Physiochemical properties, protein binding, tissue perfusion, ad diseases or age.

Drug Metabolism

• This includes chemical modifications that body makes known as metabolism, the liver transforms this for easier excretion.
• Phases of metabolism happens in the liver, reactions includes reduction often by enzymes.

Factors of Metabolism

• enzymes induce while other some can be effective when altering clearance in the drugs system, and how genetic variability activity can lead to activities amongst people.

Drug Elimination

• Drug refers to the removal of drugs within the body. such as excretion, renal and hepatic.
• Estimation for the body's ability to eliminate the drug.
• Function of diseases can decrease from the liver.

Explore the scope and history of pharmacology, from ancient practices to modern clinical applications. Review Avicenna's contributions and the role of pharmacovigilance. See how clinical pharmacologists choose treatments.