Definitions pharmacokinetics oevaluate the way in which a drug interacts with various barriers within a biological system pharmacodynamics ostudy of the relationship between systemic exposure of a drug and its biological effects on tissue oabsorption can be defined as the movement of active drug or prodrug from the site of administration across biologic. Drug absorption is determined by the drugs physicochemical properties, formulation, and route of administration. The approach used would enable a cosmetic chemist to predict the relative degree of drug absorption through skin from the physicochemical constants. Formulation factors affecting drug product performance. Pharmaceutical factors a chemical factors b physicochemical properties of drug substances 1. Physicochemical characters affecting absorption physical. Lipid water solubility coefficient is the ratio of dissolution of drug in lipid as compared to water. These include particle size, solubility, surface 2. In oral drug absorption, prediciton and assessment. Dosage forms eg, tablets, capsules, solutions, consisting of the drug plus other ingredients, are formulated to be given by various routes eg, oral, buccal, sublingual, rectal, parenteral, topical, inhalational. A knowledge of the fate of a drug, its disposition absorption, distribution, metabolism, and excretion, known by the acronym adme and pharmacokinetics the mathematical description of the rates of these processes and of concentrationtime relationships, plays a central role throughout pharmaceutical research and development. Assessing physicochemical properties of drug molecules via. Logistic regression was applied to establish the relationship between the effect of food positive, negative or no effect on auc of 92 entries and physicochemical parameters, including clinical. Review article physicochemical and physiological mechanisms for the effects of food on drug absorption.
Ideally for optimum absorption, a drug should have sufficient aq solubility to dissolve in fluids at absorption site and lipid solubility kow high enough to facilitate the partitioning of the rug in the lipoidal biomembrane i. Regarding the physicochemical factors affecting the absorption of drugs. Just as the absorption and distribution of a drug are influenced by its physicochemical properties so is its interaction with the drug metabolising enzymes. Learn vocabulary, terms, and more with flashcards, games, and other study tools. The rate and extent of oral drug absorption is determined by a complex interaction between a drugs physicochemical properties, gi physiologic factors, and the nature of the formulation administered. Physicochemical and physiological mechanisms for the.
Dressman received february 20, 1996, from the department of pharmaceutics, victorian college of pharmacy, monash university. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. However in other routes of administration the rate and efficiency is dependent on many factors and usually on ly results in partial absorption. Compare the roles of passive diffusion and carriermediated transport in drug absorption. The presence of food within the gi tract impacts significantly on transit profiles, ph, and its solubilization capacity. Physicochemical factors of drugs affecting absorption.
The approach used would enable a cosmetic chemist to predict the relative degree of drug absorption through skin from the physicochemical constants of series of compounds and the absorption data. This chapter discusses the passive diffusion of an orally absorbed drug. Molecular and physicochemical properties impacting. Winner of the standing ovation award for best powerpoint templates from presentations magazine. The absorption rates of the acylsalicylic acids were different in the intestinal regions. Laxatives and diarrhea, which speed up the passage of substances through the digestive tract, may reduce drug absorption. Ppt physicochemical properties in relation to biological. These two characteristics, rate and completeness of absorption, comprise bioavailability. Physicochemical and biopharmaceutical properties that. These properties are important for dosage form design. Physicochemical and biopharmaceutical properties that affect drug absorption of compounds absorbed by passive diffusion. Describe two types of drug interaction and explain how.
Factors related to the physicochemical properties of the drug. Sep 19, 2014 3 factors affecting drug absorption physicochemical factors. Properties pdf win32 programming is required to give optimal absorption. Factors affecting drug absorption linkedin slideshare. Physicochemical factors drug solubility and dissolution rate solubility amount of a substance called the solute that dissolves in a unit volume of a liquid substance called the solvent to form a saturated solution under specified conditions of temperature and pressure. Physicochemical properties of api impact on formulation. For the love of physics walter lewin may 16, 2011 duration. List two physiologic factors that can alter each of the processes of absorption, distribution, and excretion. Because biological membranes contain a lipid core, they represesnt a lipophilic environment. A mechanistic approach to understanding the factors affecting.
Physicochemical and physiological mechanisms for the effects. To develop a statistical model for predicting effect of food on the extent of absorption area under the curve of timeplasma concentration profile, auc of drugs based on physicochemical properties. Chart and diagram slides for powerpoint beautifully designed chart and diagram s for powerpoint with visually stunning graphics and animation effects. This chapter discusses the physicochemical properties of the drug and. Impact of physiological, physicochemical and biopharmaceutical factors in absorption and metabolism mechanisms on the drug oral bioavailability of rats and humans 480 expert opin. Pharmaceutic factors affecting drug bioavailability. The systemic absorption of a drug is dependent on 1 the physicochemical properties. Other factors such as dose and drug stability in the intestinal medium, which can significantly impact oral absorption, must also be considered. After reading this article you will learn about the pharmaceutic factors affecting drug bioavailability. Models predictive of intestinal drug absorption are important in drug development to identify compounds with promising biopharmaceutical properties. Drug absorption is the movement of a drug from its site of application into the bloodstream. As discussed in chapter 19, the rate and extent of drug absorption are influenced by the physiological factors associated with the structure and function of the gastrointestinal tract. Pdf overview of factors affecting oral drug absorption.
Physicochemical factors affecting skin absorption request pdf. Explain how bioavailability can impact drug response and product selection. Physicochemical properties effect on absorption of drugs slideshare. The bioavailability of active drug can be varied from rapid and complete absorption to a slow, sustained rate of absorption or. Physicochemical factors of drugs affecting absorption, distribution, and excretion. We classify the physicochemical characteristics of a drug molecule or particle into those that are solely related to chemical structures and those that are related to physical shape eg, crystalline forms. Sustained release oral drug delivery system an overview. Physicochemical properties of drugs 61 applying knowledge of the pka and an appreciation of the extent to which drugs ionise in solution. Drug absorption drugs merck manuals consumer version.
Our new crystalgraphics chart and diagram slides for powerpoint is a collection of over impressively designed datadriven chart and editable diagram s guaranteed to impress any audience. Physicochemical characters affecting absorption physical properties that are due to shape, size and physical form of any drug molecule, usually unaffected by chemical changes, affect the bioavailability of therapeutic moieties. The oral absorption of any chemical entity reflects a complex spectrum of events. Factors affecting drug absorption pharmaquest home pages. Physicochemical properties of drugs pharmaceutical press.
Absorption is the transfer of the drug into the bloodstream. Food, gastrointestinal ph, and models of oral drug absorption. This article throws light upon the eight main physiological factors that affect the rate of drug absorption. For example, highfiber foods and calcium supplements may bind with a drug and prevent it from being absorbed. Logistic regression was applied to establish the relationship between the effect of food positive, negative or no effect on auc of 92 entries and physicochemical parameters, including.
For most drugs, two to fivefold differences in the rate or extent of gastrointestinal absorption can occur, depending on the dosage form. These include the physicochemical properties of the administered agent, human physiology, pathology including disease state, the way the drug is presented formulated and possibly the amount that is administered dose. Physicochemical parameters affecting drug action dr. A seminar on physicochemical properties affecting drug absorption. Physiological factors and drug absorption pharmacokinetics. A mechanistic approach to understanding the factors. Download as pptx, pdf, txt or read online from scribd.
Thus by understanding the physicochemical properties of a compound and by recognizing the physiological. A drug substance is considered highly soluble when the highest dose strength is soluble in drug substance is considered highly permeable when the extent of absorption in humans is determined to be 90% of an administered dose, based on massbalance or in comparison to an. Physicochemical approaches to enhancing oral absorption. Predicting effect of food on extent of drug absorption based. Factors related to the physicochemical properties of the. Invitro dissolution testing or drug release testing may be used for seeking waiver of required product to conduct invivo bioavailability or bioequivalence studies. This chapter discusses the physicochemical properties of the drug and dosage form factors that influence bioavailability. Drug absorption depends on the lipid solubility of the drug, its formulation and the route of administration. The importance of the physicochemical properties on the dissolution of a drug substance into the dissolution medium is best illustrated by 3. Physico chemical factors affecting drug absorption youtube. The factors affecting absorption of drugs are related both to the drugs and to the body. Predicting effect of food on extent of drug absorption.
Consequently, food would be expected to affect the absorption of co. Each route of drug application presents special biopharmaceutic consideration in designing a drug product. Some basic thermodynamic concepts will be introduced, particularly that of thermodynamic activity, an important parameter in determining drug potency. Drugs are absorbed after oral administration as a consequence of a complex array of interactions between the drug, its formulation, and the gastrointestinal gi tract. Overview of factors affecting oral drug 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. Physicochemical factors affecting absorption authorstream. Several factors can affect the absorption of a drug into the body. Bioavailability physicochemical and dosage form factors. The factors affecting absorption of drugs are related both to the drugs and to the body factors related to drugs. Factors affecting drug absorption and distribution anaesthesia. In oral drug absorption, prediction and assessment.
In iv this process is complete thus the whole dose reaches the systemic circulation. Physicochemical parameters affecting drug action posted jun 29, 2014, 10. Phenols another commonly encountered acidic functional group found in drug molecules is phenol, or. Major process for absorption of more than 90% of drugs. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. Factors affecting the formulation of oral sustained release drug delivery system 1 physicochemical factors 25 1. Factors influencing product bioavailability include drug sol ubility, permeability. Write in detail about the factors that are related to the physiological conditions and formulation of dosage form. Deductions of this type form the basis ofmedicinal chemistry, the science of rational drug design.
May 29, 2018 for the love of physics walter lewin may 16, 2011 duration. Dissolution testing of immediaterelease products and its application to forcasting in vivo performance. A mechanistic approach to understanding the factors affecting drug absorption. Greater the lipid water solubility coefficient, more is the lipid solubility of the drug and greater is the absorption. A drug substance is considered highly soluble when the highest dose strength is soluble in 90% of an administered dose, based on massbalance or in comparison to an. Physicochemical properties effect on absorption of drugs. Jun 19, 2019 several factors can affect the absorption of a drug into the body. Physicochemical and physiological mechanisms for the effects of food on drug absorption. Write in brief about factors affecting drug absorption. Considerations in the design of a drug product to deliver the active drug with the desired bioavailability characteristics and therapeutic objectives include 1 the physicochemical properties of the drug molecule, 2 the type of drug product eg, tablet, capsule, transdermal delivery system, topical ointment, parenteral solution, 3 the. However, it was shown that the absorption rates in the small intestine tended to reach a ceiling at the high lipophilicity. Since permeability is a factor affecting absorption, cell culture models e. The rate and extent of oral drug absorption is determined by a complex interaction between a drugs physicochemical properties, gi physiologic factors, and the. Pharmaceutic factors affecting drug bioavailability toxicology.
In each region, the absorption rate increased with the drug lipophilicity. Mar 24, 2007 to develop a statistical model for predicting effect of food on the extent of absorption area under the curve of timeplasma concentration profile, auc of drugs based on physicochemical properties. Solubility as a limiting factor to drug absorption. Oral absorption efficiency can be influenced by several factors, acting independently or in concert. Despite the fact that these three equations are derived from different diffusion mechanisms, they clearly show that the dissolution rate depends on the solubility and surface area of a drug.
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