Physicochemical factors affecting absorption authorstream. Physicochemical and biopharmaceutical properties that affect. Poor solubility 90% of an administered dose, based on massbalance or in comparison to an. Poor solubility absorption is the process by which the drug gets from its site of administration to the central compartment, the bloodstream if you will.
Physiologic considerations in drug absorption from the. May 29, 2018 physico chemical factors affecting drug absorption vidyamitra. Molecular weight is an important physicochemical parameter that should be considered when optimizing intestinal permeability. Each route of drug application presents special biopharmaceutic consideration in designing a drug product.
The bioavailability of active drug can be varied from rapid and complete absorption to a slow, sustained rate of absorption or. Factors related to the physicochemical properties of the drug substance tue, 25 jun 2019 drug absorption the importance of the physicochemical properties on the dissolution of a drug substance into the dissolution medium is best illustrated by 3. For instance,a drug administered orally in tablet or capsule form it has to undergo disintegration and deaggregation rapidly. Drugdrug interactions memorable psychopharmacology duration. This is obviously going to be influenced by numerous properties of the drug itself, the site where it has been administered, the patients disease state and the various crude physical and chemical factors which govern the movement of substances from one. In each region, the absorption rate increased with the drug lipophilicity.
Pharmacokinetics basics absorption, distribution, metabolism. Through an awareness of a drug s physicochemical properties and the physiological processes affecting drug absorption, the skilled pharmaceutical scientist can develop formulations that will maximize product availability. The absorption rates of the acylsalicylic acids were different in the intestinal regions. Physicochemical properties effect on absorption of drugs 1. Apr 27, 2016 introduction of absorption transport process factors affecting drug absorption with examples. 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.
Pharmaceutical factors a chemical factors b physicochemical properties of drug substances 1. Due to drug treatment some time motility is increased or decreased. Pharmaceutical factors a chemical factors b physicochemical properties. Physico chemical factors affecting drug absorption vidyamitra. This chapter discusses the physicochemical properties of the drug and dosage form factors that influence bioavailability. Physicochemical factors dissolution rate dissolution rate and noyeswhitney equation physiological factors affecting dissolution rate drug factors affecting dissolution rate factors affecting concentration in the git after dissolving poorly soluble drugs dissociation of the drug molecules pka phpartition hypothesis. Jun 19, 2019 drug absorption is a pharmacokinetic parameter that refers to the way a drug is absorbed from a pharmaceutical formulation into the bloodstream. Physicochemical properties effect on absorption of drugs. 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 mechanistic approach to understanding the factors affecting. Physicochemical factors physical and chemical conditions are abiotic factors that affect the environment for geomicrobes. Factors affecting gastrointestinal absorption of drugs. Ensuring a sufficient compound concentration in solution at the primary site of absorption is a requirement for successful oral drug absorption. Some drugs are irritating and should be administered with meals to reduce adverse effects. Brodie proposed the ph partition theory to explain the influence of gi ph and drug pka on the extent of drug transfer or drug absorption. This is because movement of git wall the drug particle can easily comes in. List two physiologic factors that can alter each of the processes of absorption, distribution, and excretion. Dressman received february 20, 1996, from the department of pharmaceutics, victorian college of pharmacy, monash university. Impact of physiological, and biopharmaceutical factors in absorption and metabolism mechanisms on the drug oral bioavailability of rats and humans. Aqueous solubility of drug is a major factor that determines its dissolution rate. To predict the in who absorption characteristics of various. Through an awareness of a drugs physicochemical properties and the physiological processes affecting drug absorption, the skilled pharmaceutical scientist can. Physicochemical and physiologic factors affecting the.
It is a process by which absorption of drug from site of administration. Excipient variability did not greatly affect the impact of excipients on drug apparent solubility. Physicochemical properties of drugs affecting bioavailability. Pharmaceutic factors affecting drug bioavailability toxicology. Smt kishoritai bhoyar college of pharmacy, kamptee. Factors related to the physicochemical properties of the drug. Physicochemical and physiological mechanisms for the effects. Pdf impact of physiological, and biopharmaceutical factors. Thus by understanding the physicochemical properties of a compound and by recognizing the physiological processe affecting drug absorption, also with the awareness of a drugs bcs characteristics.
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. Regarding the physicochemical factors affecting the absorption of drugs. Physicochemical and physiologic factors affecting the absorption of warfarin in man robert a. 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. Sep 19, 2014 3 factors affecting drug absorption physicochemical factors.
Factors affecting the formulation of oral sustained release drug delivery system 1 physicochemical factors 25 1. Physico chemical factors affecting drug absorption youtube. Apr 09, 2011 the four processes involved when a drug is taken are absorption, distribution, metabolism and elimination or excretion adme. Pdf impact of physiological, and biopharmaceutical. List two physiologic factors that can alter each of the. Bioavailability physicochemical and dosage form factors. Other factors such as dose and drug stability in the intestinal medium, which can significantly impact oral absorption, must also be considered. Pdf overview of factors affecting oral drug absorption. The absorption, distribution, and excretion of drugs objectives after studying this chapter, the reader should be able to. After reading this article you will learn about the pharmaceutic factors affecting drug bioavailability. Drug absorption and factor affecting drug absorption by dr. 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 and physiologic factors affecting the absorption of. Physicochemical and physiological mechanisms for the effects of food on drug absorption. Write in detail about the factors that are related to the physiological conditions and formulation of dosage form. Physicochemical and biopharmaceutical properties that. Drug solubility solubility of drug plays a prime role in controlling its dissolution from dosage form. Drug absorption is a pharmacokinetic parameter that refers to the way a drug is absorbed from a pharmaceutical formulation into the bloodstream. Biopharmaceutic considerations in drug product design and in vitro drug product performance. Explain the meaning of the terms absorption, distribution, metabolism, and excretion.
Physicochemical factors affecting absorption authorstream presentation. Oreilly department of medicine, santa clara county hospital, san jose, and the school of medicine, university of california at san francisco. There are mainly three broad categories of factors that may affect absorption by the oral route. Solubility and permeability are considered as the major physicochemical factor that affect the rate and extent of oral drug absorption, moreover other. Physiological factors affecting absorption pharmatutor. Physicochemical and biopharmaceutical properties that affect drug absorption of compounds absorbed by passive diffusion. Although there are significant differences in the anatomy and physiology of the gastrointestinal tract, these are not associated with significant differences in the rate and extent of drug absorption between rats and humans. A drug must possess aqueous solubility for therapeutic efficacy in physiological ph range of 1 to 8 at 37.
A seminar on physicochemical properties affecting drug absorption. This article throws light upon the eight main physiological factors that affect the rate of drug absorption. Ph partition theory of drug absorption is based on the assumption that the git is a simple lipid barrier to the transport of drugs and chemicals. Variations government medical college and hospital. The first one is physicochemical characteristics which include. Physicochemical properties effect on absorption of drugs slideshare. Physicochemical factors affecting drug absorption i. Lipid water solubility coefficient is the ratio of dissolution of drug in lipid as compared to water. Depending upon the type of inhalation technology, only about 2050% of the pulmonarydelivered dose is deposited in the. The factors affecting absorption of drugs are related both to the drugs and to the body factors related to drugs. Mar 30, 2018 now this lecture from absorption of drug with factor affecting drug absorption. Thus the two critical slower rate determining process in the absorption of orally administered drugs are.
Biopharmaceutical understanding of excipient variability on. Factors affecting drug absorption and distribution anaesthesia. Some disorders like diabetic neuropathy causes gastric stasis and decrease the drug absorption. Sustained release oral drug delivery system an overview.
Pharmacokinetics is the way the body acts on the drug once it is administered. Physiological factors and drug absorption pharmacokinetics. The excessively rapid movement of git impairs absorption. Write in brief about factors affecting drug absorption. However, it was shown that the absorption rates in the small intestine tended to reach a ceiling at the high lipophilicity. Drug absorption from pulmonary epithelia occurs only after inhaled drug deposits in the lung and undeposited aerosolized particles clear out of the lung in expired air. Physicochemical and biopharmaceutical factors that influence permeability and solubility tend to be species independent.