General pharmacology 1.1 introduction to pharmacologyMangeshBansod2
This document provides an introduction to the key concepts in pharmacology including:
- Definitions of pharmacology and drugs. Pharmacology deals with drug interaction with living systems.
- The main divisions of pharmacodynamics (what the drug does to the body) and pharmacokinetics (what the body does to the drug).
- Historical landmarks in pharmacology including the development of early drugs from natural sources and landmark discoveries like penicillin.
- The scope of pharmacology including areas like pharmacotherapeutics, clinical pharmacology, chemotherapy, and toxicology.
The autonomic nervous system functions below consciousness to control visceral functions. It has two divisions - the sympathetic and parasympathetic nervous systems. The sympathetic nervous system uses norepinephrine as its primary neurotransmitter, while the parasympathetic nervous system uses acetylcholine. Neurotransmission in the autonomic nervous system involves impulse conduction, transmitter release from synaptic vesicles, transmitter action on postjunctional membranes, generation of a postjunctional potential, and termination of transmitter action through reuptake or degradation. Many neurons also release cotransmitters that can modify or substitute the action of the primary transmitter.
The document discusses neurotransmitters in the central nervous system. It defines the central nervous system and peripheral nervous system. Neurotransmitters are chemical messengers that transmit signals between neurons. The major neurotransmitters in the central nervous system are amino acids like glutamate and GABA, and amines like dopamine, serotonin, and acetylcholine. Neurotransmitters are synthesized and stored in neurons, then released into the synaptic cleft to activate receptors on the receiving neuron. This activation can be excitatory or inhibitory. The document discusses the synthesis, receptors, and functions of several important neurotransmitters like GABA, glutamate, dopamine, and acetylcholine.
The document discusses the principles of pharmacodynamics, which is the study of how drugs act on the body. It describes how drugs interact with receptors like G-protein coupled receptors, ion channels, and transmembrane receptors to exert their effects. The mechanisms of drug action include receptor binding and activation of downstream signaling pathways like the cAMP pathway or phospholipase C pathway. The document provides examples of how different receptors and signaling pathways influence various physiological processes in the body.
The autonomic nervous system is divided into the sympathetic and parasympathetic nervous systems. The sympathetic system originates from the thoracic and lumbar spinal cord and generally increases heart rate and constricts blood vessels. The parasympathetic system originates from the brainstem and sacral spinal cord and generally decreases heart rate and dilates blood vessels. Both systems work in opposition to regulate organ functions through cholinergic and adrenergic receptors.
This document provides an overview of the Pharmacology course for II Year Pharm D students at P.E.S. College of Pharmacy in Bangalore, India. The course covers general pharmacology topics including definitions, history, sources of drugs, pharmacokinetics, pharmacodynamics, and therapeutic uses of drugs. Drugs are obtained from synthetic, natural, and microbiological sources. Natural sources include plants (alkaloids, glycosides, oils, gums, resins, tannins), animals (insulin, thyroid extracts), and microbes (penicillin, chloramphenicol). The course will help students understand the basic principles of how drugs act in the body.
Gamma amino butyric acid (GABA) is the major inhibitory neurotransmitter in the mammalian central nervous system. It is synthesized from glutamate by glutamic acid decarboxylase and acts by opening chloride channels, reducing neuronal excitability. GABA acts on three main receptor types: GABAA, GABAB, and GABAC. GABAA receptors are ligand-gated chloride channels whose activation results in neuronal inhibition. Many drugs target the GABA system, including anxiolytics, sedative-hypnotics, general anesthetics, and anticonvulsants. Drugs like benzodiazepines and barbiturates enhance the effects of GABA at GAB
ddescription of hypothalamus, boundaries of hypothalamus, relation of hypothalamus, subdivision of hypothalamus, medial and lateral zone of hypothalamus, preoptic area, tuberal area and mamillary area of hypothalamus, nuclei of hypothalamus and their functions, afferent pathways of hypothalamus, efferent pathways of hypothalamus, function of hypothalamus, hormones released by hypothalamus, clinical features with hypothalamic disorders
General pharmacology 1.1 introduction to pharmacologyMangeshBansod2
This document provides an introduction to the key concepts in pharmacology including:
- Definitions of pharmacology and drugs. Pharmacology deals with drug interaction with living systems.
- The main divisions of pharmacodynamics (what the drug does to the body) and pharmacokinetics (what the body does to the drug).
- Historical landmarks in pharmacology including the development of early drugs from natural sources and landmark discoveries like penicillin.
- The scope of pharmacology including areas like pharmacotherapeutics, clinical pharmacology, chemotherapy, and toxicology.
The autonomic nervous system functions below consciousness to control visceral functions. It has two divisions - the sympathetic and parasympathetic nervous systems. The sympathetic nervous system uses norepinephrine as its primary neurotransmitter, while the parasympathetic nervous system uses acetylcholine. Neurotransmission in the autonomic nervous system involves impulse conduction, transmitter release from synaptic vesicles, transmitter action on postjunctional membranes, generation of a postjunctional potential, and termination of transmitter action through reuptake or degradation. Many neurons also release cotransmitters that can modify or substitute the action of the primary transmitter.
The document discusses neurotransmitters in the central nervous system. It defines the central nervous system and peripheral nervous system. Neurotransmitters are chemical messengers that transmit signals between neurons. The major neurotransmitters in the central nervous system are amino acids like glutamate and GABA, and amines like dopamine, serotonin, and acetylcholine. Neurotransmitters are synthesized and stored in neurons, then released into the synaptic cleft to activate receptors on the receiving neuron. This activation can be excitatory or inhibitory. The document discusses the synthesis, receptors, and functions of several important neurotransmitters like GABA, glutamate, dopamine, and acetylcholine.
The document discusses the principles of pharmacodynamics, which is the study of how drugs act on the body. It describes how drugs interact with receptors like G-protein coupled receptors, ion channels, and transmembrane receptors to exert their effects. The mechanisms of drug action include receptor binding and activation of downstream signaling pathways like the cAMP pathway or phospholipase C pathway. The document provides examples of how different receptors and signaling pathways influence various physiological processes in the body.
The autonomic nervous system is divided into the sympathetic and parasympathetic nervous systems. The sympathetic system originates from the thoracic and lumbar spinal cord and generally increases heart rate and constricts blood vessels. The parasympathetic system originates from the brainstem and sacral spinal cord and generally decreases heart rate and dilates blood vessels. Both systems work in opposition to regulate organ functions through cholinergic and adrenergic receptors.
This document provides an overview of the Pharmacology course for II Year Pharm D students at P.E.S. College of Pharmacy in Bangalore, India. The course covers general pharmacology topics including definitions, history, sources of drugs, pharmacokinetics, pharmacodynamics, and therapeutic uses of drugs. Drugs are obtained from synthetic, natural, and microbiological sources. Natural sources include plants (alkaloids, glycosides, oils, gums, resins, tannins), animals (insulin, thyroid extracts), and microbes (penicillin, chloramphenicol). The course will help students understand the basic principles of how drugs act in the body.
Gamma amino butyric acid (GABA) is the major inhibitory neurotransmitter in the mammalian central nervous system. It is synthesized from glutamate by glutamic acid decarboxylase and acts by opening chloride channels, reducing neuronal excitability. GABA acts on three main receptor types: GABAA, GABAB, and GABAC. GABAA receptors are ligand-gated chloride channels whose activation results in neuronal inhibition. Many drugs target the GABA system, including anxiolytics, sedative-hypnotics, general anesthetics, and anticonvulsants. Drugs like benzodiazepines and barbiturates enhance the effects of GABA at GAB
ddescription of hypothalamus, boundaries of hypothalamus, relation of hypothalamus, subdivision of hypothalamus, medial and lateral zone of hypothalamus, preoptic area, tuberal area and mamillary area of hypothalamus, nuclei of hypothalamus and their functions, afferent pathways of hypothalamus, efferent pathways of hypothalamus, function of hypothalamus, hormones released by hypothalamus, clinical features with hypothalamic disorders
In this presentation we will discuss Parkinsonism and other movement disorders, Pathophysiology of parkinsonism and its types, drugs used in Parkinsonism and their pharmacology and briefly discuss the drugs used to treat other movement disorders like tourettes syndrome, Huntington chorea etc.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
1. The document discusses parasympathomimetic drugs, which mimic the effects of acetylcholine (ACh) by interacting with cholinergic receptors.
2. It describes several types of parasympathomimetic drugs - direct-acting cholinergic agonists like bethanechol and pilocarpine that directly bind receptors, and anticholinesterases that inhibit the enzyme acetylcholinesterase and prolong the effects of ACh.
3. Specific drugs discussed include bethanechol, which stimulates the bladder and GI tract, pilocarpine used for dry mouth and eyes, and echothiophate, an irreversible anticholinesterase that
This document summarizes parasympathomimetics (cholinergic agonists). It discusses how the parasympathetic nervous system uses acetylcholine as a neurotransmitter and how cholinergic agonists mimic acetylcholine's actions. It classifies cholinergic agonists into direct-acting and indirect-acting types. Direct agonists bind receptors, while indirect agonists inhibit acetylcholinesterase to increase acetylcholine levels. Examples of both types are provided along with their structures, mechanisms of action, and uses. The document also covers acetylcholine synthesis and catabolism as well as structure-activity relationships of parasympathomimetics.
Cholinergic receptors,funtion and its clinical applicationDr.UMER SUFYAN M
This document discusses the history and functions of acetylcholine and cholinergic receptors. It begins with the 1936 Nobel Prize-winning discovery of acetylcholine as a neurotransmitter by Dale and Loewi. It describes the two main cholinergic receptor classes - muscarinic and nicotinic - and provides details on cholinergic drugs that act as agonists or antagonists at these receptors. These include parasympathomimetic and anticholinergic drugs used to treat various conditions like asthma, glaucoma, peptic ulcers, and Parkinson's disease. The document also discusses organophosphate poisoning and nerve agents that act by inhibiting acetylcholinesterase.
1. John Langley first postulated the concept of drug receptors in 1878 based on his experiments showing that nicotine and curare analogues interacted specifically with muscle cells to cause contraction or relaxation.
2. Paul Ehrlich further developed the drug receptor concept in the early 1900s, demonstrating that the stereochemical structure of a drug was important for its binding and interaction with receptors.
3. Receptors are specific binding sites, usually protein molecules, located on cells or within cells that drugs and neurotransmitters interact with to produce their effects. The binding of a drug or neurotransmitter to its receptor triggers signal transduction pathways that mediate the drug's ultimate physiological or pharmacological response.
Neurohumoral transmission in CNS ,special emphasis on importance of various neurotransmitters like with GABA, Glutamate, Glycine, serotonin and dopamine
The nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS). The autonomic nervous system (ANS) is a division of the PNS that regulates involuntary body functions like heart rate and digestion. The ANS has sympathetic and parasympathetic divisions that originate in the CNS and synapse in peripheral ganglia. The sympathetic division originates from the thoracic and lumbar spinal cord and the parasympathetic from cranial and sacral regions. Together with the endocrine system, the ANS coordinates essential bodily functions.
The document discusses drugs that act on the central nervous system (CNS). It describes how different drug classes such as anesthetics, anticonvulsants, tranquilizers, and stimulants can modify functions of the CNS by increasing or decreasing levels of excitatory and inhibitory neurotransmitters. Common natural neurotransmitters like glutamate, GABA, dopamine and acetylcholine are described as being either excitatory or inhibitory. The mechanisms of action for modifying the action potential are also covered. Specific CNS stimulant and anesthetic drugs are provided as examples.
This document provides information about conducting experiments using isolated tissue in pharmacology. It discusses the basic requirements needed to maintain isolated tissue, including physiological salt solutions, temperature control, aeration, tension application, and stabilization periods. Common physiological salt solutions used include Frog Ringer's, Tyrode's, Krebs, and de Jalon solutions, which aim to mimic the ionic composition of blood plasma and provide nutrients and pH buffering. Proper experimental conditions for isolated tissues help elucidate the mode of action of drugs by controlling influencing factors.
Serotonin is a monoamine neurotransmitter synthesized from tryptophan. It is found extensively in the gastrointestinal tract and in serotonergic neurons in the central nervous system. Serotonin receptors include 5-HT1-7 and are involved in various physiological functions like mood, appetite, sleep, and pain perception. Imbalances in the serotonergic system are associated with disorders like depression, anxiety, schizophrenia, and impulse control disorders. Drugs that affect the serotonergic system include SSRIs, SNRIs, triptans, 5-HT3 antagonists, buspirone, and MAOIs.
Anticonvulsant effect of drugs by MES and PTZ methodMirzaAnwarBaig1
1) The document describes experiments to test the anticonvulsant effects of drugs using maximum electroshock (MES) and pentylene tetrazole (PTZ) induced seizure models in rats and mice.
2) The experiments involve pretreating animals with test drugs or saline followed by inducing seizures using MES or PTZ and measuring the time taken for different phases of seizures.
3) Results show that pretreatment with diphenyl hydantoin sodium increases the time taken for tonic extension phase of MES induced seizures, indicating its anticonvulsant activity.
Medicinal chemistry -l-Second year-Fourth semester -medichem intro and histor...manjusha kareppa
This document provides an introduction and history of medicinal chemistry. It discusses how medicinal chemistry involves the discovery, design, and study of biologically active compounds and their mechanisms of action at the molecular level. The history section notes that ancient civilizations first used plants for medicine and key developments include the isolation of morphine in the early 19th century, the introduction of general anesthetics and antiseptics in the 1840s-1860s, and the discovery and synthesis of many modern drugs and antibiotic classes from the 1930s-1950s.
This document provides an overview of parasympathomimetic agents or cholinergic drugs. It discusses the organization of the nervous system and types of cholinergic receptors. Cholinergic drugs are classified as directly acting or indirectly acting. Directly acting drugs like choline esters and pilocarpine directly bind to muscarinic and nicotinic receptors. Indirectly acting drugs like physostigmine and neostigmine inhibit acetylcholinesterase and prolong the action of acetylcholine. These drugs have therapeutic uses in conditions like myasthenia gravis and glaucoma. Organophosphate poisoning is also discussed which occurs due to inhibition of acetylcholinesterase.
Skeletal muscle relaxants are drugs that affect skeletal muscle function by decreasing muscle tone. There are two main types: neuromuscular blockers that interfere with transmission at the neuromuscular junction and have no central nervous system activity, often used during surgery; and centrally-acting muscle relaxants that are used to alleviate musculoskeletal pain and spasms by acting in the central nervous system. Anemia is a condition in which the number of red blood cells or their oxygen-carrying capacity is insufficient, defined as a hemoglobin level below 13 g/dL for men and 12 g/dL for non-pregnant women. Anemia can be caused by blood loss, decreased red blood cell production, or increased red
The document defines four types of agents that can interact with receptors: agonists activate receptors to produce effects similar to physiological signals; antagonists prevent agonists from activating receptors without producing their own effects; partial agonists activate receptors to produce submaximal effects and also antagonize full agonists; inverse agonists activate receptors to produce effects opposite to agonists.
This document discusses neurotransmitters and neuromodulators in the central nervous system. It describes how neurotransmitters transmit signals across synapses and provides examples of small molecule and large molecule transmitters. The major neurotransmitters discussed include amino acids like GABA, glycine, and glutamate, acetylcholine, and monoamines like dopamine, norepinephrine, epinephrine, histamine, and serotonin. It outlines the synthesis, storage, release, and termination of these neurotransmitters. Receptor types are also summarized.
Pharmacodynamics is the study of how drugs act on the body and their mechanisms of action. It involves drug-receptor interactions and explains the relation between drug effects. Pharmacodynamics provides a basis for rational drug use and design. Drugs can act through stimulation, depression, irritation, replacement or cytotoxic effects on cells. Their main targets are receptors, ion channels, enzymes, and transporter proteins. Understanding drug-receptor interactions is important for explaining drug effects and determining their potency and efficacy. Drug interactions can enhance or reduce the effects of drugs and should be considered when administering multiple medications.
Pharmacodynamics is the study of the biochemical and physiological effects of drugs and their mechanisms of action. Pharmacodynamics is often referred to as “what the drug does to the body”.
In order to exert their effects, drugs usually interact in a structurally specific way with a protein receptor or act on physiological processes within the body. This activates a secondary messenger system that produces a physiological effect. Drugs do not create new action but they can only modify (alter) the functions of cells or tissues in body. The drug–receptor complex initiates alterations in biochemical and/or molecular activity of a cell by a process called signal transduction.
In this presentation we will discuss Parkinsonism and other movement disorders, Pathophysiology of parkinsonism and its types, drugs used in Parkinsonism and their pharmacology and briefly discuss the drugs used to treat other movement disorders like tourettes syndrome, Huntington chorea etc.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
1. The document discusses parasympathomimetic drugs, which mimic the effects of acetylcholine (ACh) by interacting with cholinergic receptors.
2. It describes several types of parasympathomimetic drugs - direct-acting cholinergic agonists like bethanechol and pilocarpine that directly bind receptors, and anticholinesterases that inhibit the enzyme acetylcholinesterase and prolong the effects of ACh.
3. Specific drugs discussed include bethanechol, which stimulates the bladder and GI tract, pilocarpine used for dry mouth and eyes, and echothiophate, an irreversible anticholinesterase that
This document summarizes parasympathomimetics (cholinergic agonists). It discusses how the parasympathetic nervous system uses acetylcholine as a neurotransmitter and how cholinergic agonists mimic acetylcholine's actions. It classifies cholinergic agonists into direct-acting and indirect-acting types. Direct agonists bind receptors, while indirect agonists inhibit acetylcholinesterase to increase acetylcholine levels. Examples of both types are provided along with their structures, mechanisms of action, and uses. The document also covers acetylcholine synthesis and catabolism as well as structure-activity relationships of parasympathomimetics.
Cholinergic receptors,funtion and its clinical applicationDr.UMER SUFYAN M
This document discusses the history and functions of acetylcholine and cholinergic receptors. It begins with the 1936 Nobel Prize-winning discovery of acetylcholine as a neurotransmitter by Dale and Loewi. It describes the two main cholinergic receptor classes - muscarinic and nicotinic - and provides details on cholinergic drugs that act as agonists or antagonists at these receptors. These include parasympathomimetic and anticholinergic drugs used to treat various conditions like asthma, glaucoma, peptic ulcers, and Parkinson's disease. The document also discusses organophosphate poisoning and nerve agents that act by inhibiting acetylcholinesterase.
1. John Langley first postulated the concept of drug receptors in 1878 based on his experiments showing that nicotine and curare analogues interacted specifically with muscle cells to cause contraction or relaxation.
2. Paul Ehrlich further developed the drug receptor concept in the early 1900s, demonstrating that the stereochemical structure of a drug was important for its binding and interaction with receptors.
3. Receptors are specific binding sites, usually protein molecules, located on cells or within cells that drugs and neurotransmitters interact with to produce their effects. The binding of a drug or neurotransmitter to its receptor triggers signal transduction pathways that mediate the drug's ultimate physiological or pharmacological response.
Neurohumoral transmission in CNS ,special emphasis on importance of various neurotransmitters like with GABA, Glutamate, Glycine, serotonin and dopamine
The nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS). The autonomic nervous system (ANS) is a division of the PNS that regulates involuntary body functions like heart rate and digestion. The ANS has sympathetic and parasympathetic divisions that originate in the CNS and synapse in peripheral ganglia. The sympathetic division originates from the thoracic and lumbar spinal cord and the parasympathetic from cranial and sacral regions. Together with the endocrine system, the ANS coordinates essential bodily functions.
The document discusses drugs that act on the central nervous system (CNS). It describes how different drug classes such as anesthetics, anticonvulsants, tranquilizers, and stimulants can modify functions of the CNS by increasing or decreasing levels of excitatory and inhibitory neurotransmitters. Common natural neurotransmitters like glutamate, GABA, dopamine and acetylcholine are described as being either excitatory or inhibitory. The mechanisms of action for modifying the action potential are also covered. Specific CNS stimulant and anesthetic drugs are provided as examples.
This document provides information about conducting experiments using isolated tissue in pharmacology. It discusses the basic requirements needed to maintain isolated tissue, including physiological salt solutions, temperature control, aeration, tension application, and stabilization periods. Common physiological salt solutions used include Frog Ringer's, Tyrode's, Krebs, and de Jalon solutions, which aim to mimic the ionic composition of blood plasma and provide nutrients and pH buffering. Proper experimental conditions for isolated tissues help elucidate the mode of action of drugs by controlling influencing factors.
Serotonin is a monoamine neurotransmitter synthesized from tryptophan. It is found extensively in the gastrointestinal tract and in serotonergic neurons in the central nervous system. Serotonin receptors include 5-HT1-7 and are involved in various physiological functions like mood, appetite, sleep, and pain perception. Imbalances in the serotonergic system are associated with disorders like depression, anxiety, schizophrenia, and impulse control disorders. Drugs that affect the serotonergic system include SSRIs, SNRIs, triptans, 5-HT3 antagonists, buspirone, and MAOIs.
Anticonvulsant effect of drugs by MES and PTZ methodMirzaAnwarBaig1
1) The document describes experiments to test the anticonvulsant effects of drugs using maximum electroshock (MES) and pentylene tetrazole (PTZ) induced seizure models in rats and mice.
2) The experiments involve pretreating animals with test drugs or saline followed by inducing seizures using MES or PTZ and measuring the time taken for different phases of seizures.
3) Results show that pretreatment with diphenyl hydantoin sodium increases the time taken for tonic extension phase of MES induced seizures, indicating its anticonvulsant activity.
Medicinal chemistry -l-Second year-Fourth semester -medichem intro and histor...manjusha kareppa
This document provides an introduction and history of medicinal chemistry. It discusses how medicinal chemistry involves the discovery, design, and study of biologically active compounds and their mechanisms of action at the molecular level. The history section notes that ancient civilizations first used plants for medicine and key developments include the isolation of morphine in the early 19th century, the introduction of general anesthetics and antiseptics in the 1840s-1860s, and the discovery and synthesis of many modern drugs and antibiotic classes from the 1930s-1950s.
This document provides an overview of parasympathomimetic agents or cholinergic drugs. It discusses the organization of the nervous system and types of cholinergic receptors. Cholinergic drugs are classified as directly acting or indirectly acting. Directly acting drugs like choline esters and pilocarpine directly bind to muscarinic and nicotinic receptors. Indirectly acting drugs like physostigmine and neostigmine inhibit acetylcholinesterase and prolong the action of acetylcholine. These drugs have therapeutic uses in conditions like myasthenia gravis and glaucoma. Organophosphate poisoning is also discussed which occurs due to inhibition of acetylcholinesterase.
Skeletal muscle relaxants are drugs that affect skeletal muscle function by decreasing muscle tone. There are two main types: neuromuscular blockers that interfere with transmission at the neuromuscular junction and have no central nervous system activity, often used during surgery; and centrally-acting muscle relaxants that are used to alleviate musculoskeletal pain and spasms by acting in the central nervous system. Anemia is a condition in which the number of red blood cells or their oxygen-carrying capacity is insufficient, defined as a hemoglobin level below 13 g/dL for men and 12 g/dL for non-pregnant women. Anemia can be caused by blood loss, decreased red blood cell production, or increased red
The document defines four types of agents that can interact with receptors: agonists activate receptors to produce effects similar to physiological signals; antagonists prevent agonists from activating receptors without producing their own effects; partial agonists activate receptors to produce submaximal effects and also antagonize full agonists; inverse agonists activate receptors to produce effects opposite to agonists.
This document discusses neurotransmitters and neuromodulators in the central nervous system. It describes how neurotransmitters transmit signals across synapses and provides examples of small molecule and large molecule transmitters. The major neurotransmitters discussed include amino acids like GABA, glycine, and glutamate, acetylcholine, and monoamines like dopamine, norepinephrine, epinephrine, histamine, and serotonin. It outlines the synthesis, storage, release, and termination of these neurotransmitters. Receptor types are also summarized.
Pharmacodynamics is the study of how drugs act on the body and their mechanisms of action. It involves drug-receptor interactions and explains the relation between drug effects. Pharmacodynamics provides a basis for rational drug use and design. Drugs can act through stimulation, depression, irritation, replacement or cytotoxic effects on cells. Their main targets are receptors, ion channels, enzymes, and transporter proteins. Understanding drug-receptor interactions is important for explaining drug effects and determining their potency and efficacy. Drug interactions can enhance or reduce the effects of drugs and should be considered when administering multiple medications.
Pharmacodynamics is the study of the biochemical and physiological effects of drugs and their mechanisms of action. Pharmacodynamics is often referred to as “what the drug does to the body”.
In order to exert their effects, drugs usually interact in a structurally specific way with a protein receptor or act on physiological processes within the body. This activates a secondary messenger system that produces a physiological effect. Drugs do not create new action but they can only modify (alter) the functions of cells or tissues in body. The drug–receptor complex initiates alterations in biochemical and/or molecular activity of a cell by a process called signal transduction.
This document discusses pharmacodynamics, which is the study of what a drug does to the body. It covers drug action, effect, and the various mechanisms of drug action including physical action, chemical action, interactions with regulatory proteins, receptors, and receptor families. It also discusses concepts like dose response curves, drug potency, efficacy, therapeutic index, synergism, and antagonism.
Mechanism of drug action & factor modifying drug actionDipak Bari
This document discusses pharmacodynamics and the mechanisms of drug action. It explains that pharmacodynamics is the study of biochemical and physiological effects of drugs and their mechanisms of action. The key mechanisms discussed are: receptor-mediated binding, non-receptor mediated effects, enzyme inhibition or stimulation, and physical or chemical properties. Factors that can modify a drug's action like body weight, age, drug interactions, and tolerance are also summarized.
- Pharmacology is the study of how drugs act on living systems and their effects. It is a relatively young branch of science, around 100 years old.
- Early developments included more reliance on experimentation over theorizing in the late 18th century and advances in chemistry and physiology in the 18th-20th centuries.
- Pharmacology involves studying how drugs are absorbed, distributed, metabolized and eliminated by the body as well as their interactions with receptors.
- It has many branches including pharmacokinetics, pharmacodynamics, toxicology, clinical pharmacology and others.
The document discusses various aspects of pharmacodynamics, which is the study of how drugs act on the body. It describes different mechanisms of drug action including stimulation, depression, irritation, replacement, cytotoxic action, physical action, chemical action, action through enzymes, and action through receptors. It also discusses concepts like dose-response relationship, drug potency and efficacy, therapeutic index, drug combination effects like synergism and antagonism, and factors that can modify drug action.
The document summarizes drug abuse and addiction from a neurobiological perspective. It discusses how repetitive drug use leads to adaptive changes in the brain, especially in brain circuits involved in reward and motivation. This can make drug use compulsive and difficult to stop. All addictive drugs increase dopamine levels in the brain's reward system, hijacking the brain's natural reinforcement pathways and conditioning drug-seeking behavior. Long-term drug use can cause lasting changes in the structure and function of the brain that contribute to addiction. However, treatment and abstinence can allow the brain to partially recover over time.
1. Pharmacodynamics is the study of how drugs act on the body, including their mechanisms of action.
2. Drugs primarily act by interacting with proteins like receptors, ion channels, enzymes, and transporters. They can also act physically or chemically.
3. Drugs can have stimulatory, depressant, replacement, or cytotoxic effects by interacting with enzymes, receptors, or through physical/chemical actions. The most common mechanism is receptor interaction.
Pharmacokinetics is the study of how the body affects a drug over time, including aspects like absorption, distribution, metabolism, and excretion of drugs. The four main pharmacokinetic properties that determine the onset, intensity, and duration of a drug's effects are absorption, distribution, metabolism, and excretion. Understanding a drug's pharmacokinetics allows clinicians to design optimal dosing regimens by considering factors like the route of administration, dose, dosing frequency, and duration of treatment.
Pharmacodynamics studies how drugs act on the body and their mechanisms of action. There are two types of pharmacological effects - main effects which are therapeutic, and adverse effects which are unwanted. Drugs can act through receptor mechanisms, by influencing enzymes or ion channels, or through transport systems. Their effects depend on factors like chemical structure, dose, and individual variability. Interactions between drugs can cause synergism, where effects are enhanced, or antagonism, where one drug reduces another's effects. Careful consideration of benefits and risks is needed when using drugs.
This document discusses various topics related to drug dependence, addiction, abuse, tolerance, and interactions. It provides definitions and explanations of key concepts. Some main points include:
- Drug dependence develops from repeated drug use and results in withdrawal symptoms upon cessation. It is characterized by compulsive drug seeking despite negative consequences.
- Tolerance occurs when neurons adapt to repeated drug exposure and only function normally in the drug's presence. Withdrawal syndrome can range from mild to life-threatening depending on the drug.
- The CREB protein and CRF neuropeptide are involved in the biological mechanisms of psychological dependence, forcing the body to take higher doses to achieve the same effect.
- Successful treatment involves
This document provides an introduction to basic principles of pharmacology. It defines key terminology such as efficacy, potency, therapeutic index, toxicity and adverse effects. It also describes the basic principles of pharmacokinetics including absorption, distribution, metabolism and elimination of drugs. Pharmacodynamics such as agonist and antagonist drug receptor interactions are also explained. The document provides details on pharmacokinetic processes like absorption, distribution, metabolism and excretion of drugs. It also discusses pharmacodynamic concepts including drug receptors, potency, efficacy and therapeutic index.
Posology is the science of determining drug doses. The optimal dose varies between individuals due to factors like age, health, weight, drug interactions, and rate of drug elimination from the body. Elderly and children typically require lower doses than adults. Drug effects also depend on route of administration, time of administration, environmental factors, and presence of disease. Drug interactions like additive effects, synergism, antagonism, and tolerance further complicate determining proper dosages.
Pharmacodynamics is the study of what drugs do to the body, including their mechanisms of action, pharmacological effects, and adverse effects. Drugs can act through various mechanisms including stimulation, depression, irritation, replacement, cytotoxicity, and interactions with receptors, enzymes, ion channels, antibodies, and transporters. Adverse drug reactions can be predictable based on a drug's pharmacological properties or unpredictable idiosyncratic reactions. Predictable reactions include side effects, secondary effects, toxicity, and iatrogenic disease, while unpredictable reactions include allergies and idiosyncrasies.
This document provides an overview of key concepts in pharmacology. It discusses pharmacotherapeutics, pharmacokinetics, pharmacodynamics, pharmacy, toxicology, trade names vs generic names, bioequivalence, drug development process including preclinical and clinical trials, drug scheduling, dose response curves, routes of drug administration, drug absorption and distribution, biotransformation, drug interactions, tolerance, clearance, half-life, receptor binding, agonists vs antagonists, desensitization, down-regulation, denervation supersensitivity, therapeutic index, and adverse drug events vs reactions.
Here are the matches between the pharmacologic terms and their definitions:
1. Efficacy - C) This is the maximal response obtainable by a drug treatment
2. Potency - E) This is the amount of drug required to produce a desired effect
3. Tolerance - A) Decreased response to the same dose of the drug.
4. Therapeutic index - D) This is the ratio of the toxic dose to the therapeutic dose
5. Intolerance - B) When the antagonist is suddenly withdrawn, severe reaction occurs in the form of rebound or withdrawal effects
The Pharmacological Intervention in Drug and Alcohol AddictionColleen Farrelly
This document discusses pharmacological interventions for treating drug and alcohol addiction. It describes how addiction affects the brain on a neurochemical level and how pharmacological treatments can address neurochemical imbalances and conditioned responses. There are several categories of pharmacological treatments: those for overdose reversal, maintenance to prevent withdrawal, detoxification to ease withdrawal symptoms, reducing cravings to prevent relapse, and managing pain in recovery. Key drugs discussed are naloxone for opiate overdoses, methadone and LAAM as maintenance therapies for heroin addiction, and benzodiazepines for managing alcohol withdrawal symptoms. While pharmacological treatments can help reduce harm, they are not a complete solution and must be combined with other therapies.
Cell Therapy Expansion and Challenges in Autoimmune DiseaseHealth Advances
There is increasing confidence that cell therapies will soon play a role in the treatment of autoimmune disorders, but the extent of this impact remains to be seen. Early readouts on autologous CAR-Ts in lupus are encouraging, but manufacturing and cost limitations are likely to restrict access to highly refractory patients. Allogeneic CAR-Ts have the potential to broaden access to earlier lines of treatment due to their inherent cost benefits, however they will need to demonstrate comparable or improved efficacy to established modalities.
In addition to infrastructure and capacity constraints, CAR-Ts face a very different risk-benefit dynamic in autoimmune compared to oncology, highlighting the need for tolerable therapies with low adverse event risk. CAR-NK and Treg-based therapies are also being developed in certain autoimmune disorders and may demonstrate favorable safety profiles. Several novel non-cell therapies such as bispecific antibodies, nanobodies, and RNAi drugs, may also offer future alternative competitive solutions with variable value propositions.
Widespread adoption of cell therapies will not only require strong efficacy and safety data, but also adapted pricing and access strategies. At oncology-based price points, CAR-Ts are unlikely to achieve broad market access in autoimmune disorders, with eligible patient populations that are potentially orders of magnitude greater than the number of currently addressable cancer patients. Developers have made strides towards reducing cell therapy COGS while improving manufacturing efficiency, but payors will inevitably restrict access until more sustainable pricing is achieved.
Despite these headwinds, industry leaders and investors remain confident that cell therapies are poised to address significant unmet need in patients suffering from autoimmune disorders. However, the extent of this impact on the treatment landscape remains to be seen, as the industry rapidly approaches an inflection point.
One health condition that is becoming more common day by day is diabetes.
According to research conducted by the National Family Health Survey of India, diabetic cases show a projection which might increase to 10.4% by 2030.
Adhd Medication Shortage Uk - trinexpharmacy.comreignlana06
The UK is currently facing a Adhd Medication Shortage Uk, which has left many patients and their families grappling with uncertainty and frustration. ADHD, or Attention Deficit Hyperactivity Disorder, is a chronic condition that requires consistent medication to manage effectively. This shortage has highlighted the critical role these medications play in the daily lives of those affected by ADHD. Contact : +1 (747) 209 – 3649 E-mail : sales@trinexpharmacy.com
Hiranandani Hospital in Powai, Mumbai, is a premier healthcare institution that has been serving the community with exceptional medical care since its establishment. As a part of the renowned Hiranandani Group, the hospital is committed to delivering world-class healthcare services across a wide range of specialties, including kidney transplantation. With its state-of-the-art facilities, advanced medical technology, and a team of highly skilled healthcare professionals, Hiranandani Hospital has earned a reputation as a trusted name in the healthcare industry. The hospital's patient-centric approach, coupled with its focus on innovation and excellence, ensures that patients receive the highest standard of care in a compassionate and supportive environment.
Rasamanikya is a excellent preparation in the field of Rasashastra, it is used in various Kushtha Roga, Shwasa, Vicharchika, Bhagandara, Vatarakta, and Phiranga Roga. In this article Preparation& Comparative analytical profile for both Formulationon i.e Rasamanikya prepared by Kushmanda swarasa & Churnodhaka Shodita Haratala. The study aims to provide insights into the comparative efficacy and analytical aspects of these formulations for enhanced therapeutic outcomes.
Histololgy of Female Reproductive System.pptxAyeshaZaid1
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
2. BP 404 T Pharmacology I
Ms. Kanchan chouksey
Unit I a. Introduction to Pharmacology
b. Pharmacokinetics
Unit II a. Pharmacodynamics,
b. Adverse drug reaction,
c. Drug Interactions
d. Drug discovery and clinical evaluation of new drugs
Unit III Pharmacology of drugs acting on Peripheral nervous system
Unit IV Pharmacology of Drugs acting on Central Nervous system
Unit V Pharmacology of Drugs acting on Central nervous system
3. Books
Text Books
K.D. Tripathi A Text book of Pharmacology
Sparsh gupta A textbook of Pharmacology
Reference Books
Goodman and Gilman’s A Text book of Pharmacology
Rang H.P., Dale M.M., A Text book of Pharmacology
Lippincott A Text book of Pharmacology
Other Books
Sharma H.L. , Sharma K.K., A textbook of Pharmacology,
and many others
Ms. Kanchan chouksey
4. Receptor :
These are macromolecule or binding site
located on the surface or Inside the cell that
recognise the signal , molecule, or drug and
initiate the response
Ms. Kanchan
chouksey
6. Agonist :
Agonist facilitate the receptor response.
An agonist is a mimetic of the natural ligand.
It produces a similar biological effect as the natural ligand when it binds
to the receptor.
It binds at the same binding site and leads in the absence of the natural
ligand , to either a full or partial response.
In the latter case, it is called a partial agonist.
Ms. Kanchan
chouksey
7. The figure below shows the action of ligand,
agonist, and partial agonist:
Ms. Kanchan
chouksey
8. Antagonists:
Antagonist inhibits receptor response.
As there name implies, an antagonist inhibit the effects of the natural
ligand (hormone, neurotransmitter), agonist, partial agonist, and even
inverse agonists.
Ms. Kanchan
chouksey
9. Antagonist Types :
Competitive Antagonist
Non competitive Antagonist
Ms. Kanchan chouksey
A competitive antagonist binds to the same
site as the agonist but does not activate it,
thus blocks the agonist's action.
A non-competitive antagonist binds to an
allosteric (non-agonist) site on the
receptor to prevent activation of the
receptor.
11. The following terms are used in describing drug-
receptor interaction:
Agonist- An agent which activates a receptor to produce an effect similar to that
of the physiological signal molecule.
Inverse agonist -An agent which activates a receptor to produce an effect in the
opposite direction to that of the agonist.
Antagonist- An agent which prevents the action of agonist on a receptor or the
subsequent response, but does not have any effect of its own.
Ms. Kanchan chouksey
12. Continue…
Partial agonist -
An agent which activates a receptor to produce submaximal effect but
antagonizes the action of a full agonist.
Ligand -
Any molecule which attaches selectively to particular receptors or sites.
The term only indicates affinity or ability to bind without regard to functional
change: agonists and competitive antagonist are both ligands of the same receptor.
Ms. Kanchan chouksey
13. Graded dose–response relations
Ms. Kanchan
chouksey
As the concentration of a drug increases, its pharmacologic
effect also gradually increases until all the receptors are
occupied (the maximum effect).
It is used to determine affinity, potency, efficacy
14. Affinity:
A drug's affinity refers to the chemical forces that cause a substance to
bind its receptor.
Intrinsic activity is a measure of the ability of a drug that is bound to
the receptor to generate an activating stimulus and produce a change
in cellular activity.
Both agonists and antagonists can bind to a receptor.
Ms. Kanchan
chouksey
16. Potency :
Effective concentration (EC50) is the concentration of an agonist needed
to elicit half of the maximum biological response of the agonist.
Ms. Kanchan
chouksey
E.g., Highly potent drug -
fentanyl, alprazolam , evokes a
given response at low
concentrations
while a drug of
lower potency like diazepam,
ziprasidone, evokes the same
response only at higher
concentrations
17. Efficacy:
Efficacy is a drug's capacity to produce an effect
Ms. Kanchan
chouksey
E.g.-
1. Diuretic drugs : Furosemide
eliminates much more salt and
water through urine than
hydrochlorothiazide.
2. Analgesics : aspirin is less potent
as well as less efficacious than
Morphine
3. Sedative : Diazepam is less
efficacious than pentobarbitone
19. Drug Tolerance :
Ms. Kanchan
chouksey
It refers to the requirement of higher dose of a drug to produce a given
response.
Loss of therapeutic efficacy after prolonged/intensive use of a drug.
Like sulfonylureas in type 2 diabetes , Beta-2 agonists in bronchial
asthma
Example : Before X drug 500 mg Response
Tolerance 800mg Response
20. Drug tolerance may be:
Natural
The species/individual is inherently less sensitive to the drug.
E.g. rabbits are tolerant to atropine, Hyporesponsive people for Beta blocker.
Ms. Kanchan
chouksey
21. Acquired :
This is a result of repeated use of drug in an individual was initially responsive for
the same drug.
Body is capable of developing tolerance to most drugs, but the phenomenon is very
easily recognized in the case of CNS depressants.
E.g.:
• CNS Depressant – like chlorpromazine ( sedative action ), Analgesics (Morphine) ,
Alcohol
Note : Higher dose is required for the effect of the same drug
Ms. Kanchan
chouksey
22. Cross tolerance
One drug causes tolerance to other given drug but only when both has same
pharmacological activity
It is the development of tolerance to pharmacologically related drugs
E.g.- alcoholics are relatively tolerant to barbiturates and general
anaesthetics
Why ?
Because frequent consumption of alcohol develops tolerance for
Barbiturates and General anesthetics ( Higher dose is required )
Ms. Kanchan
chouksey
23. Drug dependence :
It is an altered physiological state produced by repeated administration of a
drug which necessitates the continued presence of the drug to maintain
physiological equilibrium.
This has been earlier termed 'physical dependence’ but is now simply called
'dependence '
Ms. Kanchan
chouksey
24. Continue…
This is due to adaptation of the nervous system to function normally in the
presence of the drug, it has been also called 'neuroadaptation' .
Drugs producing dependence are - opioids, barbiturates, alcohol
Opioid dependence causes withdrawal symptoms, which makes it difficult to
stop taking them.
Ms. Kanchan
chouksey
25. Drug addiction
Ms. Kanchan
chouksey
A person is said to have developed 'drug addiction' when he/she believes
that optimal state of well being is achieved only through the actions or
the drug.
The subject feels emotionally distressed if the drug is not taken.
It often starts as liking for the drug effects and progresses to compulsive
drug use in some individuals who lose control and cannot stop taking the
drug, even if they known it to be harmful.
26. Continue…
This was earlier termed 'psychological dependence'.
However, to avoid confusion, the widely understood term 'drug addiction' is
used now.
Drug addiction is a pattern of compulsive drug use characterized by
overwhelming involvement with the use of a drug.
Amphetamines, cocaine, are CNS stimulants drugs which produce
addiction but Little/no dependence.
Results : Feeling happy, Sexual arousal , fast heart beat , pupil dilation
Ms. Kanchan
chouksey
27. Tachyphylaxis
Ms. Kanchan
chouksey
When some drugs administered repeatedly at short intervals, the cell
receptors get blocked up and pharmacological response to that drug
decreased.
The decreased response cannot be reversed by increasing the dose this
phenomenon is called tachyphylaxis or acute tolerance
E.g. ephedrine given repeated dose at short intervals in the treatment
of bronchial asthma may produce very less response due to
tachyphylaxis
28. Idiosyncrasy-
Ms. Kanchan chouksey
Non-immunological hypersenstivity of drug in specific individual without
connection to pharmacological toxicity.
Idiosyncrasy refers to genetically determined abnormal reactivity to a chemical.
Idiosyncrasy is also called as allergy.
An extraordinary response to a drug which is different from its characteristic
pharmacological action is called idiosyncrasy.
E.g. small quantity of aspirin may cause gastric hemorrhage.
E.g. some persons are sensitive to penicillin and sulphonamide because they
produce severe toxic effect.
29. Drug allergy (hypersensitivity)
It is an immunologically mediated reaction.
The symptoms may appear even with much smaller doses and have a
different time course of onset and duration.
This is also called drug hypersensitivity.
The target organs primarily affected in drug allergy are skin, airways, blood
vessels, blood cells and gastrointestinal tract.
Ms. Kanchan
chouksey
30. Continue…
The drug or its metabolite acts as an antigen (AG)
They induce production of antibody (AB)/sensitized lymphocytes.
A particular drug can produce different types of allergic reactions in different
individuals, while widely different drugs can produce similar reaction.
Example : Penicillin causes anaphylaxis, methyldopa cause hemolytic
anemia
Ms. Kanchan
chouksey
32. Pharmacokinetics (The life cycle of a Drug)
Pharmacokinetics is the quantitative study of drug movement in,
through and out of the body.
Pharmacokinetics: Pharmakon - drug and Kinesis - motion
The intensity of response is related to concentration of the drug at
the site of action.
Pharmacokinetic - determine four pharmacokinetic properties determine
the onset, intensity & duration of drug action.
Ms. Kanchan chouksey
35. Pharmacokinetics: Membrane Transport, Absorption
and Distribution of Drugs
All pharmacokinetic processes involve transport of the drug across biological
membranes.
Biological membrane:
Ms. Kanchan chouksey
36. Biological membrane:
Ms. Kanchan
chouksey
Biological membranes carry out functions that are indispensable for life.
They provide a barrier against the extracellular environment.
They also give shape to the cell, creating a matrix for insertion of proteins,
storing and transmitting energy, receiving and amplifying signals,
38. Biological membrane Composition:
Ms. Kanchan
chouksey
All Biological membrane are composed of mainly lipid and protein
molecule:
Three major types of lipids in cell membrane are:
Phospholipid -The most abundant.
Cholesterol- responsible for stabilizing the membrane.
Glycolipid- found at the external surface of the membrane.
41. Continue…
All of the lipids are described as being amphipathic as they have a
hydrophilic (water- loving) end and a hydrophobic (water-hating) end to
the molecule.
The proteins within the membrane are largely concerned with the
transport of molecules across the membrane.
Ms. Kanchan
chouksey
42. Continue…
Drugs are transported across the membranes by:
(a) Passive diffusion
(b) filtration : for low molecular weight ( less than 100)
(c) Specialized transport
(d) Active transport
Ms. Kanchan
chouksey
43. Passive diffusion:
The drug diffuses across the membrane in the direction of its concentration
gradient (high to low).
The membrane playing no active role in the process.
This is the most important mechanism for majority o f drugs.
The drugs moves from high concentration to low concentration untill the
equilibrium is maintained between extracellular and intracellular fluid
It does not require energy and depends on concentration.
Ms. Kanchan
chouksey
46. Continue…
Lipid soluble drugs diffuse by dissolving in the lipoidal matrix of the
membrane the rate of transport being proportional to the lipid
Water partition coefficient of the drug.
A more lipid-soluble drug attains higher concentration in the membrane and
diffuses quickly.
Also, greater the difference in the concentration of the drug on the two sides of
the membrane, faster is its diffusion.
Ms. Kanchan
chouksey
47. Continue..
b) Filtration : for molecule of low molecular weight (less than 100) through 7 Å pores of membrane
(1micrometer = 10000 Aangstrom)
Example : Urea , ethylene glycol (additives)
c) Bulk flow : Passage across capillary wall which pore size of 40Å.
d)Active transport:
Require energy (ATP)
It work against concentration gradient ( Higher to lower concentration)
Example : Methyldopa, Levodopa
e) Facilitated diffusion : through carrier proteins
f) Endocystosis ( outside to inside) and exocytosis( Inside to outside) through pinocytosis, phagocytosis
Ms. Kanchan
chouksey
50. Filtration
Filtration is passage of drugs through aqueous pores in the membrane or
through paracellular spaces.
This can be accelerated if hydrodynamic flow of the solvent is occurring under
hydrostatic or osmotic pressure gradient, e.g. across most capillaries including
glomeruli.
Ms. Kanchan
chouksey
51. Specialized transport
This can be carrier mediated or by vesicular transport.
Endocytosis & Exocytosis-
Ms. Kanchan
chouksey
52. ABSORPTION
Absorption is the transfer of a drug from the site of administration to the
bloodstream.
The rate and extent of absorption depend on the environment where the drug
is absorbed, chemical characteristics of the drug, and the route of
administration (which influences bioavailability).
Routes of administration other than intravenous may result in partial
absorption and lower bioavailability
Ms. Kanchan chouksey
53. Factors influencing drug absorption:
Lipid solubility of drug
pH of the medium ( stomach & intestine)
pKa of the drug
Ms. Kanchan
chouksey
54. Lipid solubility of the drug
Drugs which are lipophilic easily cross the membrane
Drugs which are lipophobic / Hydrophilic have problem crossing membrane
This is the major source of variation in drug diffusion or absorption
Only non ionized drug ( non-polar) diffuse across the cell membrane
Non polar drugs are lipid soluble
Polar drugs are water soluble , they cannot absorbs biological membrane
Lipid soluble = Non ionized molecule( NaCl)
Hydrophillic = Ionized molecule (Na+, Cl-)
Ms. Kanchan
chouksey
55. Effect of pH on drug absorption :
Ms. Kanchan
chouksey
Acidic drug better absorbed in acidic media.
Basic drug better absorbed in basic media.
Acidic drugs ( aspirin) are better absorbed in stomach in acidic media.
Basic drugs better absorbed in intestine ( alkaline media).
56. Bioavailability
Bioavailability is the rate and extent to which an administered drug reaches
the systemic circulation.
Or Bioavailability is the rate and extent of drug absorbs from its dosage form
that reach to the systemic circulation.
For example, if 100 mg of a drug is administered orally and 70 mg is absorbed
unchanged, the bioavailability is 70%.
Ms. Kanchan
chouksey
57. Objectives of Bioavailability studies:
Ms. Kanchan
chouksey
Primary stages of development of a suitable dosage form
Determination of influence of excipients (Stability and
solubility) and interaction with other drugs on the
efficiency of absorption
59. First-pass hepatic metabolism:
When a drug is absorbed from the GI tract, it enters the portal circulation
before entering the systemic circulation.
If the drug is rapidly metabolized in the liver or GIT wall during this initial
passage, the amount of unchanged drug entering the systemic circulation is
decreased.
This is referred to as first-pass metabolism.
Cytochrome P-450 enzymes metabolized many drugs.
Ms. Kanchan
chouksey
61. Continue…
First-pass metabolism by the intestine or liver limits the efficacy of many oral
medications.
For example, more than 90% of nitroglycerin (HF, HBP) is cleared during
first-pass metabolism.
Hence, it is primarily administered via the sublingual or transdermal route
Drugs with high first-pass metabolism should be given in doses sufficient
to ensure that enough active drug reaches the desired site of action.
Ms. Kanchan
chouksey
62. DISTRIBUTION
Drug distribution is the process by which a drug reversibly leaves the bloodstream and
enters the extracellular fluid and the tissues.
Phases of distribution:
First phase :
Reflect cardiac output and blood flow –
Thus heart , liver, kidney, and brain receive most of the drugs during the first few
minutes after absorption
Second phase:
Deliver to muscle, skin, adipose is slower and involves a far large fraction of the
body mass.
Ms. Kanchan
chouksey
63. Drug reservoirs:
Body compartment where a drug can accumulate are reservoirs and have
dynamic effect on drug availability
1. Plasma proteins (albumins) as reservoirs (bind drug)
2. Cellular reservoirs:
Adipose (lipophillic drug)
Bone ( crystal )
Ms. Kanchan
chouksey
66. Volume of distribution:
The volume of distribution Vd - is defined as the fluid
volume that is required to contain the entire drug in the
body at the same concentration measured in the plasma.
Ms. Kanchan
chouksey
68. Volume of distribution :
Ms. Kanchan
chouksey
100 mg
water
Vd= Amount of drug given
in body / Concentration of
drug in plasma
Vd= 100/20= 5 L
20mg / L
Concentration = Weight /
volume ( mg / L)
69. Ms. Kanchan
chouksey
Drug metabolism is the term used to describe the
biotransformation of pharmaceutical substances in
the body so that they can be eliminated more easily.
It is the enzymatic conversion from one chemical form of
a substance to another.
Metabolism is an essential pharmacokinetic process
which converts lipid soluble or non-polar compounds to
water soluble or polar compounds that they are excreted
by various processes.
Metabolism or Biotransformation:
70. Phases of Metabolism
Phase I: Non-synthetic reactions such as cleavage (e.g. oxidation,
reduction, hydrolysis), formation or modification of a function group.
Phase II: Synthetic reactions such as conjugation with an endogenous
substance (e.g. sulfate, glycine, glucuronic acid).
Examples:
Oxidation – phenytoin, barbiturates
Hydrolysis- Aspirin
Reduction- Benzodiazepines
Ms. Kanchan
chouksey
73. Phase I and Phase II enzymes:
Phase I enzymes:
Cytochrome P450, Esterase, Alcohol dehydrogenase
,Monoamine oxidase
Phase II enzymes:
Uridine Diphosphate-glucuronosyl transferase (UDPGT)
(Catalyse the covalent addition of glucuronic acid with lipophilic
chemicals)
Sulfo transferase ( sulphonation increases water solublity of
lipophilic drugs)
Ms. Kanchan
chouksey
74. Metabolic enzyme:
Ms. Kanchan
chouksey
Microsomal enzyme
Found in smooth endoplasmic reticulum of liver cells.
Example: CYP- 450, mono oxygenase
Non- microsomal enzymes:
Found in cytoplasm and mitochondria of liver cells.
Example: Alcholol dehydrogenase,
76. Drugs and their metabolites are excreted in:
1. Urine –
Drug excretion in urine occurs via the kidney.
It is the most important channel of excretion for majority of drugs.
2. Faeces –
Apart from the unabsorbed fraction, most of the drug present in faeces is
derived from bile.
Liver actively transports into bile organic acids
Ms. Kanchan
chouksey
77. Continue..
3. Milk –
The excretion or drug in milk is not important for the mother.
Most drugs enter breast milk by passive diffusion.
As such. more lipid soluble and less protein bound drugs cross better.
Milk has a lower pH (7.0) than plasma, basic drugs are somewhat more concentrated
in it.
Ms. Kanchan
chouksey