Food, other drugs, and digestive disorders can affect drug absorption and bioavailability. The absorption rates of the acylsalicylic acids were different in the intestinal regions. Formulation factors affecting drug product performance. For example, highfiber foods and calcium supplements may bind with a drug and prevent it from being absorbed. The presence of food within the gi tract impacts significantly on transit profiles, ph, and its solubilization capacity. In oral drug absorption, prediciton and assessment. Physicochemical and physiological mechanisms for the. The rate and extent of oral drug absorption is determined by a complex. Some basic thermodynamic concepts will be introduced, particularly that of thermodynamic activity, an important parameter in determining drug potency. The systemic absorption of a drug is dependent on 1 the physicochemical properties. Physicochemical characters affecting absorption physical. A mechanistic approach to understanding the factors affecting drug absorption. The rate and extent of oral drug absorption is determined by a complex interaction between a drugs physicochemical properties, gi physiologic factors, and the.
However, it was shown that the absorption rates in the small intestine tended to reach a ceiling at the high lipophilicity. Sustained release oral drug delivery system an overview. Impact of physiological, physicochemical and biopharmaceutical factors in absorption and metabolism mechanisms on the drug oral bioavailability of rats and humans 480 expert opin. Factors affecting drug absorption pharmaquest home pages.
Physicochemical properties effect on absorption of drugs. 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. Compare the roles of passive diffusion and carriermediated transport in drug absorption. 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. Factors affecting the formulation of oral sustained release drug delivery system 1 physicochemical factors 25 1. Physicochemical approaches to enhancing oral absorption. Physicochemical factors of drugs affecting absorption. Molecular and physicochemical properties impacting. Physicochemical parameters affecting drug action dr. Download as pptx, pdf, txt or read online from scribd. 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. Solubility as a limiting factor to drug absorption.
Factors affecting drug absorption and distribution anaesthesia. A mechanistic approach to understanding the factors affecting. For the love of physics walter lewin may 16, 2011 duration. 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. Drug absorption is determined by the drugs physicochemical properties, formulation, and route of administration. Phenols another commonly encountered acidic functional group found in drug molecules is phenol, or. Laxatives and diarrhea, which speed up the passage of substances through the digestive tract, may reduce drug absorption. 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. This article throws light upon the eight main physiological factors that affect the rate of drug absorption. This chapter discusses the physicochemical properties of the drug and dosage form factors that influence bioavailability.
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. Models predictive of intestinal drug absorption are important in drug development to identify compounds with promising biopharmaceutical properties. Ppt physicochemical properties in relation to biological. Explain how bioavailability can impact drug response and product selection. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. The oral absorption of any chemical entity reflects a complex spectrum of events. Physicochemical factors affecting skin absorption request pdf. 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. Physicochemical properties effect on absorption of drugs slideshare. Physicochemical factors affecting absorption authorstream. Physicochemical and physiological mechanisms for the effects. The importance of the physicochemical properties on the dissolution of a drug substance into the dissolution medium is best illustrated by 3. Pdf impact of physiological, and biopharmaceutical.
In each region, the absorption rate increased with the drug lipophilicity. Physicochemical properties of drugs pharmaceutical press. These properties are important for dosage form design. Describe two types of drug interaction and explain how. 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.
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. 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. Learn vocabulary, terms, and more with flashcards, games, and other study tools. This chapter discusses the physicochemical properties of the drug and. Invitro dissolution testing or drug release testing may be used for seeking waiver of required product to conduct invivo bioavailability or bioequivalence studies. After reading this article you will learn about the pharmaceutic factors affecting drug bioavailability.
Pharmaceutical factors a chemical factors b physicochemical properties of drug substances 1. Physiological factors and drug absorption pharmacokinetics. Factors influencing product bioavailability include drug sol ubility, permeability. Factors affecting drug absorption linkedin slideshare. A mechanistic approach to understanding the factors. Properties pdf win32 programming is required to give optimal absorption. Review article physicochemical and physiological mechanisms for the effects of food on drug absorption. Since permeability is a factor affecting absorption, cell culture models e.
The factors affecting absorption of drugs are related both to the drugs and to the body. 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. 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. Winner of the standing ovation award for best powerpoint templates from presentations magazine. Consequently, food would be expected to affect the absorption of co. Physicochemical and biopharmaceutical properties that. In iv this process is complete thus the whole dose reaches the systemic circulation. Greater the lipid water solubility coefficient, more is the lipid solubility of the drug and greater is the absorption. Chart and diagram slides for powerpoint beautifully designed chart and diagram s for powerpoint with visually stunning graphics and animation effects. The approach used would enable a cosmetic chemist to predict the relative degree of drug absorption through skin from the physicochemical constants. Thus by understanding the physicochemical properties of a compound and by recognizing the physiological. Bioavailability physicochemical and dosage form factors. Oral absorption efficiency can be influenced by several factors, acting independently or in concert.
Regarding the physicochemical factors affecting the absorption of drugs. Overview of factors affecting oral drug absorption. Assessing physicochemical properties of drug molecules via. Sep 19, 2014 3 factors affecting drug absorption physicochemical factors. For most drugs, two to fivefold differences in the rate or extent of gastrointestinal absorption can occur, depending on the dosage form. 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. These two characteristics, rate and completeness of absorption, comprise bioavailability. Physicochemical parameters affecting drug action posted jun 29, 2014, 10. Because biological membranes contain a lipid core, they represesnt a lipophilic environment.
May 29, 2018 for the love of physics walter lewin may 16, 2011 duration. Physico chemical factors affecting drug absorption youtube. Physicochemical factors of drugs affecting absorption, distribution, and excretion. This chapter discusses the passive diffusion of an orally absorbed drug. 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.
Drug absorption is the movement of a drug from its site of application into the bloodstream. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect. However in other routes of administration the rate and efficiency is dependent on many factors and usually on ly results in partial absorption. 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. Pharmaceutic factors affecting drug bioavailability. Dressman received february 20, 1996, from the department of pharmaceutics, victorian college of pharmacy, monash university. Other factors such as dose and drug stability in the intestinal medium, which can significantly impact oral absorption, must also be considered. In oral drug absorption, prediction and assessment. Drug absorption drugs merck manuals consumer version. Factors related to the physicochemical properties of the. List two physiologic factors that can alter each of the processes of absorption, distribution, and excretion. Write in brief about factors affecting drug absorption. 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. The factors affecting absorption of drugs are related both to the drugs and to the body factors related to drugs.
Physicochemical and biopharmaceutical properties that affect drug absorption of compounds absorbed by passive diffusion. Jun 19, 2019 several factors can affect the absorption of a drug into the body. 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. Food, gastrointestinal ph, and models of oral drug absorption. Physicochemical properties of api impact on formulation. 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. Physicochemical properties of drugs 61 applying knowledge of the pka and an appreciation of the extent to which drugs ionise in solution. Predicting effect of food on extent of drug absorption. Dissolution testing of immediaterelease products and its application to forcasting in vivo performance. 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. Drug absorption depends on the lipid solubility of the drug, its formulation and the route of administration. Deductions of this type form the basis ofmedicinal chemistry, the science of rational drug design. Major process for absorption of more than 90% of drugs. 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.
Absorption is the transfer of the drug into the bloodstream. Pharmacists must also understand the relationship of drug dosage to therapeutic efficacy. 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. 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. 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. A seminar on physicochemical properties affecting drug absorption. Several factors can affect the absorption of a drug into the body. The bioavailability of active drug can be varied from rapid and complete absorption to a slow, sustained rate of absorption or. Predicting effect of food on extent of drug absorption based. Just as the absorption and distribution of a drug are influenced by its physicochemical properties so is its interaction with the drug metabolising enzymes. These include particle size, solubility, surface 2. 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. Physicochemical and physiological mechanisms for the effects of food on drug absorption. Pharmaceutic factors affecting drug bioavailability toxicology.
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