Lipid water solubility coefficient is the ratio of dissolution of drug in lipid as compared to water. Pharmaceutic factors affecting drug bioavailability toxicology. Physicochemical properties effect on absorption of drugs. Variations government medical college and hospital. After reading this article you will learn about the pharmaceutic factors affecting drug bioavailability.
Drug solubility solubility of drug plays a prime role in controlling its dissolution from dosage form. Other factors such as dose and drug stability in the intestinal medium, which can significantly impact oral absorption, must also be considered. Dressman received february 20, 1996, from the department of pharmaceutics, victorian college of pharmacy, monash university. Physicochemical factors affecting drug absorption i.
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 and factor affecting drug absorption by dr. List two physiologic factors that can alter each of the processes of absorption, distribution, and excretion. 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. The first one is physicochemical characteristics which include. Pdf impact of physiological, and biopharmaceutical factors. Due to drug treatment some time motility is increased or decreased. This chapter discusses the physicochemical properties of the drug and dosage form factors that influence bioavailability. The bioavailability of active drug can be varied from rapid and complete absorption to a slow, sustained rate of absorption or. Physicochemical and biopharmaceutical properties that affect drug absorption of compounds absorbed by passive diffusion. Factors affecting drug absorption and distribution anaesthesia. Bioavailability physicochemical and dosage form factors. Factors related to the physicochemical properties of the drug. 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.
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. Molecular weight is an important physicochemical parameter that should be considered when optimizing intestinal permeability. Solubility and permeability are considered as the major physicochemical factor that affect the rate and extent of oral drug absorption, moreover other. 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. Pdf overview of factors affecting oral drug absorption. Excipient variability did not greatly affect the impact of excipients on drug apparent solubility. Some drugs are irritating and should be administered with meals to reduce adverse effects. Pharmacokinetics basics absorption, distribution, metabolism. Physicochemical properties effect on absorption of drugs slideshare.
Factors affecting the formulation of oral sustained release drug delivery system 1 physicochemical factors 25 1. Physicochemical properties effect on absorption of drugs 1. For instance,a drug administered orally in tablet or capsule form it has to undergo disintegration and deaggregation rapidly. 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. The excessively rapid movement of git impairs absorption. Physicochemical properties of drugs affecting bioavailability. Physicochemical and biopharmaceutical properties that affect. Explain the meaning of the terms absorption, distribution, metabolism, and excretion. Pharmaceutical factors a chemical factors b physicochemical properties of drug substances 1. Write in brief about factors affecting drug absorption.
To predict the in who absorption characteristics of various. Drugdrug interactions memorable psychopharmacology duration. Poor solubility 90% of an administered dose, based on massbalance or in comparison to an. In each region, the absorption rate increased with the drug lipophilicity. A seminar on physicochemical properties affecting drug absorption. Apr 09, 2011 the four processes involved when a drug is taken are absorption, distribution, metabolism and elimination or excretion adme. 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. A drug must possess aqueous solubility for therapeutic efficacy in physiological ph range of 1 to 8 at 37. Depending upon the type of inhalation technology, only about 2050% of the pulmonarydelivered dose is deposited in the. Physicochemical and physiologic factors affecting the. Through an awareness of a drugs physicochemical properties and the physiological processes affecting drug absorption, the skilled pharmaceutical scientist can. Mar 30, 2018 now this lecture from absorption of drug with factor affecting drug absorption. 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.
Physiological factors affecting absorption pharmatutor. Each route of drug application presents special biopharmaceutic consideration in designing a drug product. Pharmaceutical factors a chemical factors b physicochemical properties. Biopharmaceutic considerations in drug product design and in vitro drug product performance. Pharmacokinetics is the way the body acts on the drug once it is administered. Physicochemical and physiologic factors affecting the absorption of warfarin in man robert a. May 29, 2018 physico chemical factors affecting drug absorption vidyamitra. Physicochemical factors affecting absorption authorstream. List two physiologic factors that can alter each of the.
Physicochemical and physiologic factors affecting the absorption of. 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. The absorption rates of the acylsalicylic acids were different in the intestinal regions. Physicochemical and biopharmaceutical properties that. The factors affecting absorption of drugs are related both to the drugs and to the body factors related to drugs.
It is a process by which absorption of drug from site of administration. Physico chemical factors affecting drug absorption vidyamitra. 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. 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. Biopharmaceutical understanding of excipient variability on. This article throws light upon the eight main physiological factors that affect the rate of drug absorption. Physicochemical factors physical and chemical conditions are abiotic factors that affect the environment for geomicrobes. There are mainly three broad categories of factors that may affect absorption by the oral route. Physiologic considerations in drug absorption from the. 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 physiological mechanisms for the effects of food on drug absorption. Drug absorption is a pharmacokinetic parameter that refers to the way a drug is absorbed from a pharmaceutical formulation into the bloodstream. Pdf impact of physiological, and biopharmaceutical. Regarding the physicochemical factors affecting the absorption of drugs.
Some disorders like diabetic neuropathy causes gastric stasis and decrease the drug absorption. This is because movement of git wall the drug particle can easily comes in. Oreilly department of medicine, santa clara county hospital, san jose, and the school of medicine, university of california at san francisco. 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. Thus the two critical slower rate determining process in the absorption of orally administered drugs are. Write in detail about the factors that are related to the physiological conditions and formulation of dosage form. 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. Smt kishoritai bhoyar college of pharmacy, kamptee. A mechanistic approach to understanding the factors affecting. Physiological factors and drug absorption pharmacokinetics. Physico chemical factors affecting drug absorption youtube.
Physicochemical factors affecting absorption authorstream presentation. 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. 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. Ensuring a sufficient compound concentration in solution at the primary site of absorption is a requirement for successful oral drug absorption. Physicochemical and biopharmaceutical factors that influence permeability and solubility tend to be species independent.
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