Request pdf factors affecting drug absorption and distribution the pharmacokinetic properties of a drug comprise the relationship between its absorption, distribution and inactivation. Many factors can influence a drug shortage and often there are multiple causes that can affect the shortage of a single drug product. Factors affecting drug absorption and distribution request pdf. Jun 26, 2007 this animation presents 4 major factors that effect a drugs distribution in the body. Factors affecting distribution of drug tissue permeability of drug 1. Request pdf general principles of drug distribution pharmacokinetics is the study. The action of a drug requires the presence of an adequate concentration of the drug in the fluid bathing the target tissue, and this, in turn, is determined by the dynamic relationship between absorption into the plasma following administration, the extent and rate of its distribution and the rate of inactivation by the body. For most tissues, passive aqueous diffusion through channels. Factors affecting drug distribution distribution of drugs throughout the body fluid is not equal. Selfreported data gathered from females 12 to 15 years of age in two northwestern communities in the united states showed an association among gender identity, peer and parental relationships, and substance use. List the assumptions made about drug distribution patterns in both one and twocompartment models. Maternal factors dose and duration of therapy low dose, infrequent dosing, short duration if drug contraindicated, may consider pump and dump route of administration drugs given iv before of poor po bioavailability are usually poorly absorbed by infant through milk drug pharmacokinetics. Factors affecting drug distribution through infusion.
Greater the lipid water solubility coefficient, more is the lipid solubility of the drug and greater is the absorption. There are many factors that affect a drugs distribution throughout an organism, but pascuzzo considers that the most important ones are the following. Drug distribution refers to the movement of drug to and from the blood and various tissues of the body e. Physiologic factors related to drug absorption applied. Because so many factors affect drug response, doctors must choose a drug appropriate for each person and must adjust the dose carefully. This animation presents 4 major factors that effect a drugs distribution in the body. Chapter objectives list physiological factors that influence drugs and may lead to an altered response.
This process depends on blood flow, capillary permeability, the degree of drug binding to. Differences in drug distribution among the tissue essentially arise as result of a number of factors. As the name implies, this is the stage when the drug is distributed to the bodys tissues. The drug distribution is usually varied, and depends on several factors such as. Describe situations in which routine clinical pharmacokinetic monitoring would be advantageous. Preventing drug use among children and adolescents redbook. Factors affecting distribution of drug linkedin slideshare. Drug distribution impact factor omics international. The primary mechanism of drug movement is passive diffusion, with the amount of transfer dependent on physiochemical properties. Factors affecting renal excretion of drugs include. Drug distribution impact factor omics internationalclinical. Rate of distribution membrane permeability we have already covered some material about membrane permeability.
General principles of drug distribution request pdf researchgate. Inside the body, drugs move in the blood to different parts of the body. Factors affecting drug absorption and distribution anaesthesia. Social determinants of drug use national drug and alcohol. Organs of high perfusion, protein binding, molecular size, and polarity. The bioavailability of active drug can be varied from rapid and complete absorption to a slow, sustained rate of absorption or. The following table highlights some of these other factors. Oct 24, 2014 contents definition factors affecting drug distribution a tissue permeability of the drug b organtissue size and perfusion rate c binding of drugs to tissue components d miscellaneous volume of distribution significance one compartment open model non compartment method references 4. Pharmaceutic factors affecting drug bioavailability. The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of similar kind. Impaired renal function may lead to a clinically significant accumulation of drugs eliminated by the kidneys, if more than 50% of the dose is normally excreted unchanged in the urine and the renal function is less than 50% of the. Organs of high perfusion, protein binding, molecular size. Factors affecting drug abuse in adolescent females in rural. Convection enhanced delivery ced is a technique used to distribute drugs inside the brain parenchyma using pressure to cause the movement of infused fluid.
The process of drug movement after absorption into various body. The action of a drug requires the presence of an adequate concentration of the drug in the fluid bathing the target tissue, and this, in turn, is determined by the dynamic relationship between absorption into the plasma following administration, the extent and rate of its distribution and the rate of. Affinity of drug for tissue constituents plasmatissue protein binding. For poorly perfused tissues eg, muscle, fat, distribution is very slow, especially if the tissue has a high affinity for the drug. Distribution into vascular and extra vascular spaces important factor elimination kinetics v d and tp describe distribution characteristics v d volume of distribution prediction of drug dosage regimen v d relates concentration of drug in blood to total amount of drug in body tp rate of drug concentration. Factors affecting dissolution rate divided into five classes a. Fulltext pdf drugs used to treat joint and muscle disease. Pathological and physiological factors affecting drug. Overview on global pharmaceutical industry according to sesric 2011 the global pharmaceutical industry has proved a rapid growth over the years and emerged as one of.
Factors affecting drug distribution through infusion by the infusion physics study group 051809 convection enhanced delivery ced is a technique used to distribute drugs inside the brain parenchyma using pressure to cause the movement of infused fluid. Pdf overview of factors affecting oral drug absorption. Generic drugs can be certified as bioequivalent by the fda and substituted for brandname drugs by a pharmacist. Particle size of the drugs, proteins binding, surface area of the drug, excretion, ph, temperature, physical volume of the body etc. Each route of drug application presents special biopharmaceutic consideration in designing a drug product. Factors affecting drug action flashcards from mandy d. This concept is related to multicompartmentalization. The analysis of the influence factors affecting the performance of pharmaceutical companies 25 25 1.
Preventing drug use among children and adolescents. The aim of this study is to detect the prevalence of substance use among tenthgrade students. Membrane permeability tends to restrict the transfer and distribution of drugs once they are delivered to the tissue. A variety of factors contribute to drug use and other problem outcomes, both individual and environmental. Distribution of a drug is not uniform throughout the body because different tissues receive the drug from plasma at different rates and to different extents. There are many factors that affect a drug s distribution throughout an organism, but pascuzzo considers that the most important ones are the following. Some drugs are not affected by food, while the absorption of a third group of drugs is enhanced by food bile secretion by liver in response to food in gi tract increases drug absorption. A thorough knowledge ofthe chemical and physical stability of drugs and dosage forms is criticalin the development andevaluationofpharmaceuticals. The other major factor which determines the rate of drug distribution is blood perfusion. Introduction to pharmacokinetics and pharmacodynamics ashp. Factors affecting drug distribution rate of distribution membrane permeability.
Pharmacists must also understand the relationship of drug dosage to therapeutic efficacy. Factors affecting drug absorption and distribution. Drug distribution to tissues merck manuals professional edition. Ratio of blood flow to tissue mass sa for drug transfer to tissue 4. Lipid water solubility coefficient is the ratio of dissolution of drug in lipid as compared to water. Factors affecting drug distribution rate of distribution membrane permeability blood perfusion extent of distribution lipid solubility ph pka plasma protein binding intracellular binding membrane permeability the walls of capillaries are very thin, consisting of only a single layer of endothelial cells, making. Physiological properties of drug pka, lipid solubility, etc. After a drug has entered tissues, drug distribution to the interstitial fluid is determined primarily by perfusion. Factors affecting drug distribution through infusion by the. The drugs are present in free or bound form and different processes or mechanisms affect their distribution. The analysis of the influence factors affecting the. Tissue permeability of drugs a physicochemical properties of drug like. Aspe research brief office of the assistant secretary for.
Responding to these risks before they become problems can be difficult. Important factors affecting the choice of channels of distribution by the manufacturer are. The process of transferring a drug from the bloodstream to tissues is referred to as distribution. Factors affecting drug abuse 2 abstract this article explores factors influencing adolescent female substance use in rural communities. Contents definition factors affecting drug distribution a tissue permeability of the drug b organtissue size and perfusion rate c binding of drugs to tissue components d miscellaneous volume of distribution significance one compartment open model non compartment method references 4. Convection enhanced delivery ced is a technique used to distribute drugs inside the brain parenchyma using pressure to cause the movement.
Factors that influence distribution include blood perfusion, membrane permeability, plasma protein binding ppb, regional ph gradients, and. When a manufacturer selects some channel of distribution heshe should take care of such factors which are related to the quality and nature of the product. Over 10 million scientific documents at your fingertips. The large alveolar area and blood supply lead to rapid absorption into the blood. Drug distribution to tissues clinical pharmacology. After reading this article you will learn about the pharmaceutic factors affecting drug bioavailability. The systemic absorption of a drug is dependent on 1 the physicochemical properties of. Another factor influencing drug distribution is the preferential binding to plasma proteins and tissues 7. Amount of drug that exists in unionized form and in ionized form is a function of pka of drug and ph of the fluid at the absorption site, and it can be determined by handersonhasselbach equation. Blood perfusion rate the rate at which blood perfuses to different organs varies widely. Other factors affecting drug absorption and distribution. The plasma and the ecf volume also increase but there is a fall in albumin content.
Drug absorption, drug distribution, drug dissolution, drug solubility introduction. Evaluation of risk factors affecting substance use among. Pharmaceutical factors a chemical factors b physicochemical properties of drug substances 1. The process by which a drug reversibly leaves the blood stream and enters the interstitium extracellular fluid andor the cells or tissues. Overview of response to drugs msd manual consumer version.
These factors may affect how the body absorbs the drug, how the body breaks down metabolizes and eliminates the drug, or what effects the drug has on the body. Factors that influence drug distribution affect the rate and delivery of drugs. Overview of factors affecting oral drug absorption naining song a,b, shaoy u zhang b, changxiao liu a a tianjin state key laboratory of pharmacokinetics and pharmaco dynamics, tianjin inst. An introduction to pharmacokinetics rmi pharmacokinetics. The drug supply system is complex and includes multiple organizations that play varied and occasionally overlapping roles in drug distribution and contracting. The factors affecting absorption of drugs are related both to the drugs and to the body. The time for drug distribution is generally measured by the distribution halflife or the time for 50% distribution. Other obvious examples include nicotine and tetrahydrocannabinol thc, which are absorbed following inhalation of tobacco or marijuana smoke. Molecular size, pka, ow partition coefficient b physiological barriers to diffusion of drugs 2. Preventing drug use among children and adolescents national institute on drug abuse karen l. Affinity of drug for tissue constituents plasmatissue. The passage of drug from the gut into the blood is influenced by biologic and physicochemical factors discussed in detail. In addition to protein availability, other factors may affect drug absorption and distribution in the body as a whole or at specific sites within the body.
Membrane structure and function the cell membrane is a semipermeable lipoid sieve containing numerous aqueous channels, as well as a variety of specialized carrier molecules. Drug distribution an overview sciencedirect topics. Drug distribution is the process of delivering a drug from the bloodstream to the tissues of the body especially the tissue s where its actions are needed. Possible factors affecting this stage include the rate of blood flow perfusion to the tissue, the tissue mass itself, and vascular and tissue membrane permeability. Describe the absorption process and factors that affect it. The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of. Volatile anesthetics, as well as many drugs which affect pulmonary function, are administered as aerosols. Factors affecting drug abuse in adolescent females in. While drug prevention and treatment have traditionally focused on changing individual behaviours, such efforts can have only limited impact when changes are not made to the environment, that is, to the social determinants of drug use. This study is descriptive and crosssectional conducted between april and may 2016. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Although averylarge number ofstudies on the subject of stability have appeared in the primary pharmaceutical literature, books onthe subjecthave notbeen comprehensive. The factors affecting absorption of drugs are related both to the drugs and to the body factors related to drugs. Identify factors that cause interpatient variability in drug disposition and drug response.
Request pdf factors affecting drug absorption and distribution the pharmacokinetic properties of a drug comprise the relationship between its absorption. In order to develop a drug product that elicits the desired therapeutic objective, the pharmaceutical scientist must have a thorough understanding of the biopharmaceutic properties of the drug and drug product and the physiologic and pathologic factors affecting drug absorption from the application site. Introduction to pharmacokinetics and pharmacodynamics. Feb 27, 2019 drug distribution is a subject that is covered in a branch of pharmacology called pharmacokinetics.
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