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. 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. Phenols another commonly encountered acidic functional group found in drug molecules is phenol, or. Drug absorption is determined by the drugs physicochemical properties, formulation, and route of administration. Drug absorption depends on the lipid solubility of the drug, its formulation and the 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.
Pharmaceutical factors a chemical factors b physicochemical properties of drug substances 1. Pharmacists must also understand the relationship of drug dosage to therapeutic efficacy. In oral drug absorption, prediciton and assessment. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. Several factors can affect the absorption of a drug into the body. However in other routes of administration the rate and efficiency is dependent on many factors and usually on ly results in partial 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. Thus by understanding the physicochemical properties of a compound and by recognizing the physiological. After reading this article you will learn about the pharmaceutic factors affecting drug bioavailability. Physicochemical factors affecting absorption authorstream. These include particle size, solubility, surface 2. 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.
In each region, the absorption rate increased with the drug lipophilicity. Jun 19, 2019 several factors can affect the absorption of a drug into the body. Some basic thermodynamic concepts will be introduced, particularly that of thermodynamic activity, an important parameter in determining drug potency. May 29, 2018 for the love of physics walter lewin may 16, 2011 duration. Physicochemical and physiological mechanisms for the effects of food on drug absorption. 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.
The presence of food within the gi tract impacts significantly on transit profiles, ph, and its solubilization capacity. The factors affecting absorption of drugs are related both to the drugs and to the body factors related to drugs. Physicochemical approaches to enhancing oral absorption. Drug absorption is the movement of a drug from its site of application into the bloodstream. The rate and extent of oral drug absorption is determined by a complex interaction between a drugs physicochemical properties, gi physiologic factors, and the.
The factors affecting absorption of drugs are related both to the drugs and to the body. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. Physicochemical parameters affecting drug action dr. A mechanistic approach to understanding the factors.
Factors affecting drug absorption and distribution anaesthesia. Physico chemical factors affecting drug absorption youtube. Physicochemical and biopharmaceutical properties that. Physicochemical and biopharmaceutical properties that affect drug absorption of compounds absorbed by passive diffusion. 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. 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. For most drugs, two to fivefold differences in the rate or extent of gastrointestinal absorption can occur, depending on the dosage form.
Factors affecting the formulation of oral sustained release drug delivery system 1 physicochemical factors 25 1. Overview of factors affecting oral drug absorption. This article throws light upon the eight main physiological factors that affect the rate of drug absorption. 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. Pdf overview of factors affecting oral drug absorption. Just as the absorption and distribution of a drug are influenced by its physicochemical properties so is its interaction with the drug metabolising enzymes. Pharmaceutic factors affecting drug bioavailability. Physicochemical properties of drugs 61 applying knowledge of the pka and an appreciation of the extent to which drugs ionise in solution.
Regarding the physicochemical factors affecting the absorption of drugs. Factors related to the physicochemical properties of the. Because biological membranes contain a lipid core, they represesnt a lipophilic environment. Physicochemical characters affecting absorption physical. Food, gastrointestinal ph, and models of oral drug absorption. Factors influencing product bioavailability include drug sol ubility, permeability. Physicochemical and physiological mechanisms for the. Pdf impact of physiological, and biopharmaceutical. Drug absorption drugs merck manuals consumer version. The systemic absorption of a drug is dependent on 1 the physicochemical properties. Major process for absorption of more than 90% of drugs. Pharmaceutic factors affecting drug bioavailability toxicology.
Physicochemical properties effect on absorption of drugs. 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. Physicochemical properties effect on absorption of drugs slideshare. 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. 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.
Invitro dissolution testing or drug release testing may be used for seeking waiver of required product to conduct invivo bioavailability or bioequivalence studies. Physiological factors and drug absorption pharmacokinetics. The oral absorption of any chemical entity reflects a complex spectrum of events. Physicochemical factors of drugs affecting absorption. Sep 19, 2014 3 factors affecting drug absorption physicochemical factors. This chapter discusses the physicochemical properties of the drug and dosage form factors that influence bioavailability. Laxatives and diarrhea, which speed up the passage of substances through the digestive tract, may reduce drug absorption. Each route of drug application presents special biopharmaceutic consideration in designing a drug product. A mechanistic approach to understanding the factors affecting drug absorption. Learn vocabulary, terms, and more with flashcards, games, and other study tools. 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. 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. Predicting effect of food on extent of drug absorption based. 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.
However, it was shown that the absorption rates in the small intestine tended to reach a ceiling at the high lipophilicity. Physicochemical properties of drugs pharmaceutical press. The rate and extent of oral drug absorption is determined by a complex. Physicochemical properties of api impact on formulation. Factors affecting drug absorption linkedin slideshare. In this chapter we examine some of the important physicochemical properties of drugs in aqueous solution which are of relevance to such liquid dosage forms as injections, solutions, and eye drops. Physicochemical factors affecting skin absorption request pdf. 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.
Consequently, food would be expected to affect the absorption of co. Assessing physicochemical properties of drug molecules via. Solubility as a limiting factor to drug 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 physicochemical properties of the drug and. Download as pptx, pdf, txt or read online from scribd. Factors related to the physicochemical properties of the drug. Winner of the standing ovation award for best powerpoint templates from presentations magazine. Properties pdf win32 programming is required to give optimal absorption. Formulation factors affecting drug product performance. Describe two types of drug interaction and explain how. Models predictive of intestinal drug absorption are important in drug development to identify compounds with promising biopharmaceutical properties.
Absorption is the transfer of the drug into the bloodstream. Lipid water solubility coefficient is the ratio of dissolution of drug in lipid as compared to water. Molecular and physicochemical properties impacting. Review article physicochemical and physiological mechanisms for the effects of food on drug absorption. The bioavailability of active drug can be varied from rapid and complete absorption to a slow, sustained rate of absorption or. Jun 25, 2019 the importance of the physicochemical properties on the dissolution of a drug substance into the dissolution medium is best illustrated by 3. In iv this process is complete thus the whole dose reaches the systemic circulation. Explain how bioavailability can impact drug response and product selection. The importance of the physicochemical properties on the dissolution of a drug substance into the dissolution medium is best illustrated by 3. Impact of physiological, physicochemical and biopharmaceutical factors in absorption and metabolism mechanisms on the drug oral bioavailability of rats and humans 480 expert opin. 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. Physicochemical factors of drugs affecting absorption, distribution, and excretion. Physicochemical parameters affecting drug action posted jun 29, 2014, 10.
Food, other drugs, and digestive disorders can affect drug absorption and bioavailability. A mechanistic approach to understanding the factors affecting. 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. These two characteristics, rate and completeness of absorption, comprise bioavailability.
Physicochemical and physiological mechanisms for the effects. These properties are important for dosage form design. Chart and diagram slides for powerpoint beautifully designed chart and diagram s for powerpoint with visually stunning graphics and animation effects. Other factors such as dose and drug stability in the intestinal medium, which can significantly impact oral absorption, must also be considered. For example, highfiber foods and calcium supplements may bind with a drug and prevent it from being absorbed. Write in brief about factors affecting drug absorption. List two physiologic factors that can alter each of the processes of absorption, distribution, and excretion. Factors affecting drug absorption pharmaquest home pages. Bioavailability physicochemical and dosage form factors. For the love of physics walter lewin may 16, 2011 duration. A seminar on physicochemical properties affecting drug absorption.
Biopharmaceutics is the study of the physicochemical properties of the drug and the drug product, in vitro, on the bioavailability of the drug, in vivo, to produce a desired therapeutic effect. Sustained release oral drug delivery system an overview. 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. Oral absorption efficiency can be influenced by several factors, acting independently or in concert. In oral drug absorption, prediction and assessment. Compare the roles of passive diffusion and carriermediated transport in drug absorption. This chapter discusses the passive diffusion of an orally absorbed drug. Predicting effect of food on extent of drug absorption. Deductions of this type form the basis ofmedicinal chemistry, the science of rational drug design. Ppt physicochemical properties in relation to biological. Dissolution testing of immediaterelease products and its application to forcasting in vivo performance. 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. Since permeability is a factor affecting absorption, cell culture models e. Greater the lipid water solubility coefficient, more is the lipid solubility of the drug and greater is the absorption.
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