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54-440: Pharmaceutics is also called the science of dosage form design. There are many chemicals with pharmacological properties, but need special measures to help them achieve therapeutically relevant amounts at their sites of action. Branches of pharmaceutics include: Pharmaceutics deals with the formulation of a pure drug substance into a dosage form . Pure drug substances are usually white crystalline or amorphous powders. Before

108-417: A magnesium ion unless the cell is also experiencing depolarization . These differences show that agonists have unique mechanisms of action depending on the receptor activated and the response needed. The goal and process remains generally consistent however, with the primary mechanism of action requiring the binding of the agonist and the subsequent changes in conformation to cause the desired response at

162-680: A myograph , and physiological responses are recorded after drug application, allowed analysis of drugs' effects on tissues. The development of the ligand binding assay in 1945 allowed quantification of the binding affinity of drugs at chemical targets. Modern pharmacologists use techniques from genetics , molecular biology , biochemistry , and other advanced tools to transform information about molecular mechanisms and targets into therapies directed against disease, defects or pathogens, and create methods for preventive care, diagnostics, and ultimately personalized medicine . The discipline of pharmacology can be divided into many sub disciplines each with

216-526: A biological response. A physiological agonist is a substance that creates the same bodily responses but does not bind to the same receptor. New findings that broaden the conventional definition of pharmacology demonstrate that ligands can concurrently behave as agonist and antagonists at the same receptor, depending on effector pathways or tissue type. Terms that describe this phenomenon are " functional selectivity ", "protean agonism", or selective receptor modulators . As mentioned above, agonists have

270-448: A dispensing or clinical care role. In either field, the primary contrast between the two is their distinctions between direct-patient care, pharmacy practice, and the science-oriented research field, driven by pharmacology. The word pharmacology is derived from Greek word φάρμακον , pharmakon , meaning "drug" or " poison ", together with another Greek word -λογία , logia with the meaning of "study of" or "knowledge of" (cf.

324-454: A drug is used therapeutically, it is important to understand the margin of safety that exists between the dose needed for the desired effect and the dose that produces unwanted and possibly dangerous side-effects (measured by the TD 50 , the dose that produces toxicity in 50% of individuals). This relationship, termed the therapeutic index , is defined as the ratio TD 50 : ED 50 . In general,

378-440: A drug will affect the rate and extent of absorption, extent of distribution, metabolism and elimination. The drug needs to have the appropriate molecular weight, polarity etc. in order to be absorbed, the fraction of a drug the reaches the systemic circulation is termed bioavailability, this is simply a ratio of the peak plasma drug levels after oral administration and the drug concentration after an IV administration(first pass effect

432-503: A full agonist, antagonists have affinity for a receptor but do not produce a biological response. The ability of a ligand to produce a biological response is termed efficacy , in a dose-response profile it is indicated as percentage on the y-axis, where 100% is the maximal efficacy (all receptors are occupied). Binding affinity is the ability of a ligand to form a ligand-receptor complex either through weak attractive forces (reversible) or covalent bond (irreversible), therefore efficacy

486-495: A narrow therapeutic margin: toxic side-effects are almost always encountered at doses used to kill tumors . The effect of drugs can be described with Loewe additivity which is one of several common reference models. Other models include the Hill equation , Cheng-Prusoff equation and Schild regression . Pharmacokinetics is the study of the bodily absorption, distribution, metabolism, and excretion of drugs. When describing

540-416: A specific focus. Pharmacology can also focus on specific systems comprising the body. Divisions related to bodily systems study the effects of drugs in different systems of the body. These include neuropharmacology , in the central and peripheral nervous systems ; immunopharmacology in the immune system. Other divisions include cardiovascular , renal and endocrine pharmacology. Psychopharmacology

594-412: Is SPORCalc. A slight alteration to the chemical structure of a medicinal compound could alter its medicinal properties, depending on how the alteration relates to the structure of the substrate or receptor site on which it acts: this is called the structural activity relationship (SAR). When a useful activity has been identified, chemists will make many similar compounds called analogues, to try to maximize

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648-948: Is a stub . You can help Misplaced Pages by expanding it . Pharmacology Pharmacology is the science of drugs and medications, including a substance's origin, composition, pharmacokinetics , pharmacodynamics , therapeutic use, and toxicology . More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function. If substances have medicinal properties, they are considered pharmaceuticals . The field encompasses drug composition and properties, functions, sources, synthesis and drug design , molecular and cellular mechanisms , organ/systems mechanisms, signal transduction/cellular communication, molecular diagnostics , interactions , chemical biology , therapy, and medical applications and antipathogenic capabilities. The two main areas of pharmacology are pharmacodynamics and pharmacokinetics . Pharmacodynamics studies

702-720: Is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the agonist, while an inverse agonist causes an action opposite to that of the agonist. From the Greek αγωνιστής (agōnistēs), contestant; champion; rival < αγων (agōn), contest, combat; exertion, struggle < αγω (agō), I lead, lead towards, conduct; drive Receptors can be activated by either endogenous agonists (such as hormones and neurotransmitters ) or exogenous agonists (such as drugs ), resulting in

756-637: Is a subfield of pharmacology that combines principles from pharmacology, systems biology, and network analysis to study the complex interactions between drugs and targets (e.g., receptors or enzymes etc.) in biological systems. The topology of a biochemical reaction network determines the shape of drug dose-response curve as well as the type of drug-drug interactions, thus can help designing efficient and safe therapeutic strategies. The topology Network pharmacology utilizes computational tools and network analysis algorithms to identify drug targets, predict drug-drug interactions, elucidate signaling pathways, and explore

810-594: Is a vital concern to medicine , but also has strong economical and political implications. To protect the consumer and prevent abuse, many governments regulate the manufacture, sale, and administration of medication. In the United States , the main body that regulates pharmaceuticals is the Food and Drug Administration ; they enforce standards set by the United States Pharmacopoeia . In

864-412: Is an act related to drug policy. Prescription drugs are drugs regulated by legislation. The International Union of Basic and Clinical Pharmacology , Federation of European Pharmacological Societies and European Association for Clinical Pharmacology and Therapeutics are organisations representing standardisation and regulation of clinical and scientific pharmacology. Agonists An agonist

918-399: Is avoided and therefore no amount drug is lost). A drug must be lipophilic (lipid soluble) in order to pass through biological membranes this is true because biological membranes are made up of a lipid bilayer (phospholipids etc.) Once the drug reaches the blood circulation it is then distributed throughout the body and being more concentrated in highly perfused organs. In the United States ,

972-434: Is dependent on binding affinity. Potency of drug is the measure of its effectiveness, EC 50 is the drug concentration of a drug that produces an efficacy of 50% and the lower the concentration the higher the potency of the drug therefore EC 50 can be used to compare potencies of drugs. Medication is said to have a narrow or wide therapeutic index , certain safety factor or therapeutic window . This describes

1026-493: Is intended to fall within a range in which the drug produces a therapeutic effect or desired outcome. The safety and effectiveness of prescription drugs in the U.S. are regulated by the federal Prescription Drug Marketing Act of 1987 . The Medicines and Healthcare products Regulatory Agency (MHRA) has a similar role in the UK. Medicare Part D is a prescription drug plan in the U.S. The Prescription Drug Marketing Act (PDMA)

1080-508: Is the application of genomic technologies to drug discovery and further characterization of drugs related to an organism's entire genome. For pharmacology regarding individual genes, pharmacogenetics studies how genetic variation gives rise to differing responses to drugs. Pharmacoepigenetics studies the underlying epigenetic marking patterns that lead to variation in an individual's response to medical treatment. Pharmacology can be applied within clinical sciences. Clinical pharmacology

1134-493: Is the application of pharmacological methods and principles in the study of drugs in humans. An example of this is posology, which is the study of dosage of medicines. Pharmacology is closely related to toxicology . Both pharmacology and toxicology are scientific disciplines that focus on understanding the properties and actions of chemicals. However, pharmacology emphasizes the therapeutic effects of chemicals, usually drugs or compounds that could become drugs, whereas toxicology

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1188-399: Is the study of chemical's adverse effects and risk assessment. Pharmacological knowledge is used to advise pharmacotherapy in medicine and pharmacy . Drug discovery is the field of study concerned with creating new drugs. It encompasses the subfields of drug design and development . Drug discovery starts with drug design, which is the inventive process of finding new drugs. In

1242-414: Is the study of the effects of used pharmaceuticals and personal care products (PPCPs) on the environment after their elimination from the body. Human health and ecology are intimately related so environmental pharmacology studies the environmental effect of drugs and pharmaceuticals and personal care products in the environment . Drugs may also have ethnocultural importance, so ethnopharmacology studies

1296-419: Is the study of the use of drugs that affect the psyche , mind and behavior (e.g. antidepressants) in treating mental disorders (e.g. depression). It incorporates approaches and techniques from neuropharmacology, animal behavior and behavioral neuroscience, and is interested in the behavioral and neurobiological mechanisms of action of psychoactive drugs. The related field of neuropsychopharmacology focuses on

1350-608: The European Union , the main body that regulates pharmaceuticals is the EMA , and they enforce standards set by the European Pharmacopoeia . The metabolic stability and the reactivity of a library of candidate drug compounds have to be assessed for drug metabolism and toxicological studies. Many methods have been proposed for quantitative predictions in drug metabolism; one example of a recent computational method

1404-426: The Food and Drug Administration (FDA) is responsible for creating guidelines for the approval and use of drugs. The FDA requires that all approved drugs fulfill two requirements: Gaining FDA approval usually takes several years. Testing done on animals must be extensive and must include several species to help in the evaluation of both the effectiveness and toxicity of the drug. The dosage of any drug approved for use

1458-568: The Middle Ages , with pharmacognosy and Avicenna 's The Canon of Medicine , Peter of Spain 's Commentary on Isaac , and John of St Amand 's Commentary on the Antedotary of Nicholas . Early pharmacology focused on herbalism and natural substances, mainly plant extracts. Medicines were compiled in books called pharmacopoeias . Crude drugs have been used since prehistory as a preparation of substances from natural sources. However,

1512-465: The active ingredient of crude drugs are not purified and the substance is adulterated with other substances. Traditional medicine varies between cultures and may be specific to a particular culture, such as in traditional Chinese , Mongolian , Tibetan and Korean medicine . However much of this has since been regarded as pseudoscience . Pharmacological substances known as entheogens may have spiritual and religious use and historical context. In

1566-603: The etymology of pharmacy ). Pharmakon is related to pharmakos , the ritualistic sacrifice or exile of a human scapegoat or victim in Ancient Greek religion . The modern term pharmacon is used more broadly than the term drug because it includes endogenous substances, and biologically active substances which are not used as drugs. Typically it includes pharmacological agonists and antagonists , but also enzyme inhibitors (such as monoamine oxidase inhibitors). The origins of clinical pharmacology date back to

1620-428: The muscarinic acetylcholine receptor and NMDA receptor and their respective agonists. For the muscarinic acetylcholine receptor , which is a G protein-coupled receptor (GPCR), the endogenous agonist is acetylcholine . The binding of this neurotransmitter causes the conformational changes that propagate a signal into the cell. The conformational changes are the primary effect of the agonist, and are related to

1674-475: The 17th century, the English physician Nicholas Culpeper translated and used pharmacological texts. Culpeper detailed plants and the conditions they could treat. In the 18th century, much of clinical pharmacology was established by the work of William Withering . Pharmacology as a scientific discipline did not further advance until the mid-19th century amid the great biomedical resurgence of that period. Before

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1728-518: The NMDA receptor requires both the endogenous agonists , N-methyl-D-aspartate (NMDA) and glycine . These co-agonists are both required to induce the conformational change needed for the NMDA receptor to allow flow through the ion channel , in this case calcium. An aspect demonstrated by the NMDA receptor is that the mechanism or response of agonists can be blocked by a variety of chemical and biological factors. NMDA receptors specifically are blocked by

1782-442: The advent of medicine as a science, it was common for pharmacists to dispense drugs as is . Most drugs today are administered as parts of a dosage form. The clinical performance of drugs depends on their form of presentation to the patient. Pharmaceutics is a specialization in the field of pharmacy. Typically, Pharm-D graduates can choose to continue studies in this field towards a PhD degree. This pharmacy -related article

1836-415: The agonist's binding affinity and agonist efficacy . Other agonists that bind to this receptor will fall under one of the different categories of agonist mentioned above based on their specific binding affinity and efficacy. The NMDA receptor is an example of an alternate mechanism of action, as the NMDA receptor requires co-agonists for activation. Rather than simply requiring a single specific agonist,

1890-404: The biological approach of finding targets and physiological effects. Pharmacology can be studied in relation to wider contexts than the physiology of individuals. For example, pharmacoepidemiology concerns the variations of the effects of drugs in or between populations, it is the bridge between clinical pharmacology and epidemiology . Pharmacoenvironmentology or environmental pharmacology

1944-458: The concentration of agonist needed to elicit half of the maximum biological response of the agonist. The EC 50 value is useful for comparing the potency of drugs with similar efficacies producing physiologically similar effects. The smaller the EC 50 value, the greater the potency of the agonist, the lower the concentration of drug that is required to elicit the maximum biological response. When

1998-405: The cost and benefits of drugs in order to guide optimal healthcare resource allocation. The techniques used for the discovery , formulation , manufacturing and quality control of drugs discovery is studied by pharmaceutical engineering , a branch of engineering . Safety pharmacology specialises in detecting and investigating potential undesirable effects of drugs. Development of medication

2052-533: The desired medicinal effect(s). This can take anywhere from a few years to a decade or more, and is very expensive. One must also determine how safe the medicine is to consume, its stability in the human body and the best form for delivery to the desired organ system, such as tablet or aerosol. After extensive testing, which can take up to six years, the new medicine is ready for marketing and selling. Because of these long timescales, and because out of every 5000 potential new medicines typically only one will ever reach

2106-898: The effect of the body on the chemical (e.g. half-life and volume of distribution ), and pharmacodynamics describes the chemical's effect on the body (desired or toxic ). Pharmacology is typically studied with respect to particular systems, for example endogenous neurotransmitter systems . The major systems studied in pharmacology can be categorised by their ligands and include acetylcholine , adrenaline , glutamate , GABA , dopamine , histamine , serotonin , cannabinoid and opioid . Molecular targets in pharmacology include receptors , enzymes and membrane transport proteins . Enzymes can be targeted with enzyme inhibitors . Receptors are typically categorised based on structure and function. Major receptor types studied in pharmacology include G protein coupled receptors , ligand gated ion channels and receptor tyrosine kinases . Network pharmacology

2160-399: The effects of a drug on biological systems, and pharmacokinetics studies the effects of biological systems on a drug. In broad terms, pharmacodynamics discusses the chemicals with biological receptors , and pharmacokinetics discusses the absorption , distribution, metabolism , and excretion (ADME) of chemicals from the biological systems. Pharmacology is not synonymous with pharmacy and

2214-449: The effects of drugs at the overlap between the nervous system and the psyche. Pharmacometabolomics , also known as pharmacometabonomics, is a field which stems from metabolomics , the quantification and analysis of metabolites produced by the body. It refers to the direct measurement of metabolites in an individual's bodily fluids, in order to predict or evaluate the metabolism of pharmaceutical compounds, and to better understand

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2268-626: The environment. The study of chemicals requires intimate knowledge of the biological system affected. With the knowledge of cell biology and biochemistry increasing, the field of pharmacology has also changed substantially. It has become possible, through molecular analysis of receptors , to design chemicals that act on specific cellular signaling or metabolic pathways by affecting sites directly on cell-surface receptors (which modulate and mediate cellular signaling pathways controlling cellular function). Chemicals can have pharmacologically relevant properties and effects. Pharmacokinetics describes

2322-452: The ethnic and cultural aspects of pharmacology. Photopharmacology is an emerging approach in medicine in which drugs are activated and deactivated with light . The energy of light is used to change for shape and chemical properties of the drug, resulting in different biological activity. This is done to ultimately achieve control when and where drugs are active in a reversible manner, to prevent side effects and pollution of drugs into

2376-513: The first pharmacology department in England was set up in 1905 at University College London . Pharmacology developed in the 19th century as a biomedical science that applied the principles of scientific experimentation to therapeutic contexts. The advancement of research techniques propelled pharmacological research and understanding. The development of the organ bath preparation, where tissue samples are connected to recording devices, such as

2430-431: The most basic sense, this involves the design of molecules that are complementary in shape and charge to a given biomolecular target. After a lead compound has been identified through drug discovery, drug development involves bringing the drug to the market. Drug discovery is related to pharmacoeconomics , which is the sub-discipline of health economics that considers the value of drugs Pharmacoeconomics evaluates

2484-500: The open market, this is an expensive way of doing things, often costing over 1 billion dollars. To recoup this outlay pharmaceutical companies may do a number of things: The inverse benefit law describes the relationship between a drugs therapeutic benefits and its marketing. When designing drugs, the placebo effect must be considered to assess the drug's true therapeutic value. Drug development uses techniques from medicinal chemistry to chemically design drugs. This overlaps with

2538-438: The pharmacokinetic profile of a drug. Pharmacometabolomics can be applied to measure metabolite levels following the administration of a drug, in order to monitor the effects of the drug on metabolic pathways. Pharmacomicrobiomics studies the effect of microbiome variations on drug disposition, action, and toxicity. Pharmacomicrobiomics is concerned with the interaction between drugs and the gut microbiome . Pharmacogenomics

2592-481: The pharmacokinetic properties of the chemical that is the active ingredient or active pharmaceutical ingredient (API), pharmacologists are often interested in L-ADME : Drug metabolism is assessed in pharmacokinetics and is important in drug research and prescribing. Pharmacokinetics is the movement of the drug in the body, it is usually described as 'what the body does to the drug' the physico-chemical properties of

2646-422: The polypharmacology of drugs. Pharmacodynamics is defined as how the body reacts to the drugs. Pharmacodynamics theory often investigates the binding affinity of ligands to their receptors. Ligands can be agonists , partial agonists or antagonists at specific receptors in the body. Agonists bind to receptors and produce a biological response, a partial agonist produces a biological response lower than that of

2700-455: The potential to bind in different locations and in different ways depending on the type of agonist and the type of receptor. The process of binding is unique to the receptor-agonist relationship, but binding induces a conformational change and activates the receptor. This conformational change is often the result of small changes in charge or changes in protein folding when the agonist is bound. Two examples that demonstrate this process are

2754-524: The ratio of desired effect to toxic effect. A compound with a narrow therapeutic index (close to one) exerts its desired effect at a dose close to its toxic dose. A compound with a wide therapeutic index (greater than five) exerts its desired effect at a dose substantially below its toxic dose. Those with a narrow margin are more difficult to dose and administer, and may require therapeutic drug monitoring (examples are warfarin , some antiepileptics , aminoglycoside antibiotics ). Most anti- cancer drugs have

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2808-403: The receptor. This response as discussed above can vary from allowing flow of ions to activating a GPCR and transmitting a signal into the cell . Potency is the amount of agonist needed to elicit a desired response. The potency of an agonist is inversely related to its half maximal effective concentration (EC 50 ) value. The EC 50 can be measured for a given agonist by determining

2862-485: The second half of the nineteenth century, the remarkable potency and specificity of the actions of drugs such as morphine , quinine and digitalis were explained vaguely and with reference to extraordinary chemical powers and affinities to certain organs or tissues. The first pharmacology department was set up by Rudolf Buchheim in 1847, at University of Tartu, in recognition of the need to understand how therapeutic drugs and poisons produced their effects. Subsequently,

2916-438: The two terms are frequently confused. Pharmacology, a biomedical science , deals with the research, discovery, and characterization of chemicals which show biological effects and the elucidation of cellular and organismal function in relation to these chemicals. In contrast, pharmacy, a health services profession, is concerned with the application of the principles learned from pharmacology in its clinical settings; whether it be in

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