Ppt drug absorption powerpoint presentation free to. An index at the beginning of the guide lists essential drugs by their inn and their corresponding pages. The larger section at the back of the eye is filled with a colorless gelatinous mass called the vitreous humor. Drug metabolism will be covered in the next chapter. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. Request pdf drug absorption, distribution, and elimination the chapter provides basic quantitative explanations of practical pharmacokinetic concepts that are key to understanding how drugs. Other approach to enhance the dissolution and absorption rate of certain drugs is by formation of in situ salt formation i. Lecture 3 drug absorption 9 sep 2006 cell membrane. Unless a drug is directly applied to, or in the vicinity of, the target site, absorption must occur for a drug to exert its therapeutic effect. Small molecules diffuse more rapidly than large molecules. Drug absorption clinical pharmacology merck manuals. Worlds best powerpoint templates crystalgraphics offers more powerpoint templates than anyone else in the world, with over 4 million to choose from. Physicochemical and physiological mechanisms for the effects.
Majority of drugs are administered extravascularly generally orally. Acidic ph favors acidic drug absorption while basic ph is better for basic drugs. Although many drugs appear to be absorbed readily when inhaled as sprays, aerosols, smokes, or dusts, knowledge of the extent and rate of absorption is incomplete. Introduction a drug may be defined as a therapeutic substance intended to affect the structure or function of the body in order to restore abnormal function to normal. Moreover, the drug s pharmacokinetic profile can be easily and significantly changed by adjusting factors that affect absorption. Pdf overview of factors affecting oral drug absorption. Key factors influencing adme properties of therapeutic. The anatomy and physiology of the drug absorption site. Drug absorption drugs merck manuals consumer version. Some drugs are irritating and should be administered with meals to reduce adverse effects. Rather, it is more likely that genes combine to create. Length of time the drug is in the stomach has a major affect on drug absorption. Director clinical pharmacology program september 30, 2010 office of clinical research training and medical education national institutes of health clinical center goals of drug absorption and bioavailability lecture factors affecting drug absorption estimation of.
First, the drug needs to be introduced via some route of administration oral, topicaldermal, etc. To understand the full clearance mechanisms of the drug and its metabolites in humans typically single dose, healthy males n46, at. The absorption, distribution, and excretion of drugs objectives after studying this chapter, the reader should be able to. A good example of competitive inhibition of drug absorption via active transport is the impaired absorption of levodopa when ingested with meals rich in proteins. Poorly watersoluble drugs that are coadministered with either food or lipidbased formulations can benefit from the processes involved with lipid digestion through enhanced wetting and solubilization facilitated by the. Mar 06, 2007 some of the advantages of colonic delivery for these types of drugs include the reduced concentration of enzymes such as peptidases that degrade peptide drugs, the colon is a site with significant absorption due to the long residence time in this part of the gastrointestinal tract, it exhibits enhanced sensitivity to absorption enhancers.
Drugdrug, drugformulation and drugmeal interactions are of clinical concern for orally administered drugs that possess a narrow therapeutic index. Drug absorption and bioavailability course materials. Most drugs are absorbed by passive absorption but some drugs need carrier mediated transport. In contrast, the concentration of highly permeable drugs, antipyrine and metoprolol, decreased quickly in the upper part of the intestine and a significant amount of drugs was not. Note that substancespecific portions of orally administered drugs are removed with feces without entering the circulation. Drug absorption is the movement of a drug from its site of application into the bloodstream. It also occurs by subcutaneous, intra muscular and transdermal routes of administration of drugs. For example, highfiber foods and calcium supplements may bind with a drug and prevent it from being absorbed.
Drug absorption, distribution, and elimination request pdf. Depending on drug pka and whether it is acidic or basic, absorption depends on the amount of unionised form at site of absorption. The small surface area and short residence time in the stomach limits gastric absorption, however, gastric retentive systems can be used for local action in the stomach e. Winner of the standing ovation award for best powerpoint templates from presentations magazine. Characteristics of the drug that influence absorption include particle size, solubility, lipophilicity, stability, ionization state pka, and polymorphism. Director clinical pharmacology program october 1, 2015 office of clinical research training and medical education national institutes of health clinical center. List two physiologic factors that can alter each of the. Biopharmaceutical aspects of intestinal drug absorption diva portal. Apr 09, 2011 absorption is the movement of a drug from its site of administration into the blood. Because of the ultrasensitivity of the lung tissue to foreign substances, administration of drugs by inhalation should probably not be widely adopted. Explain the meaning of the terms absorption, distribution, metabolism, and excretion.
In contrast, some drugs undergo multiple cycles of absorption and excretion with the bile enterohepatic circulation. Laxatives and diarrhea, which speed up the passage of substances through the digestive tract, may reduce drug absorption. A drugs dissolve rapidly in the alkaline medium whereas w. The principal site of absorption of orally administered drugs is the small intestine, due to its large surface area 250 m 2 and its epithelium, through which fluid readily filters as a result of osmotic differences caused by the presence of food.
Essential drugs are drugs that satisfy the health care needs of the majority of the population. The chemical composition of a drug, as well as the environment into which a drug is placed, work together to determine the rate and extent of. Physicochemical and physiological mechanisms for the. Binding of drugs to proteins in blood is a major determinant of pks and a source of toxic drugdrug interaction binding generally depends on charge and water solubility. Before drugs can be clinically effective, they must be absorbed. Evidencebased absorption, distribution, metabolism, excretion. According to the absorption of water luminal concentration of atenolol, a drug with low permeability, was elevated and exceeded the initial dose concentration.
Review article physicochemical and physiological mechanisms for the effects of food on drug absorption. Masaoka y1, tanaka y, kataoka m, sakuma s, yamashita s. The drug molecule combine with carrier protein and then it transferred drug to the other side of membrane, there it leaves the molecule and come back to. Pdf strategies for absorption screening in drug discovery and. Absorption interactions have been classified on the basis of ratelimiting processes. Absorption is the process of a drug moving from its site of delivery into the bloodstream.
Absorption for drugs administered via an extravascular route, the first barrier to reaching the site of action is absorption into the bloodstream, which can be controlled both by properties of the drug and of this article has not been copyedited and formatted. However, the absorptive process does not occur during direct injection of drug by intravenous or intra arterial injection. The chemical composition of a drug, as well as the environment into which a drug is placed, work together to determine the rate and extent of drug absorption. The drug molecule combine with carrier protein and then it transferred drug to the other side of membrane, there it leaves the molecule and come back to normal situation or form. Anatomy of the eye the inside of the eyeball is divided by the lens into two fluidfilled sections. These drugs are necessary to treat most of the more serious and frequent diseases. For drugs applied at their target, such as local anesthetics, absorption often terminates the therapeutic effect. Absorption is affected by blood flow, pain stress etc. These drugs have the best benefitsrisks ratio in their therapeutic classification. Scribd is the worlds largest social reading and publishing site. Theyll give your presentations a professional, memorable appearance the kind of sophisticated look that todays audiences expect.
List two physiologic factors that can alter each of the processes of absorption, distribution, and excretion. Many drugs additionally are secreted into the proximal tubule through. Drug absorption is determined by the drug s physicochemical properties, formulation, and route of administration. 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. Director clinical pharmacology program october 1, 2015 office of clinical research training and medical education national institutes of. Drug absorption from the colon in situ springerlink. Increase peristalsis movement decrease rate of absorption as drug no remain in git for long time.
Targeting receptors, transporters and site of absorption to. A classification table gives you information about the therapeutic group of. Abrahamsson, in comprehensive medicinal chemistry ii, 2007. Amerge pharmacokinetics absorption bioavailability. 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.
Sometimes these characteristics work against each other to improve absorption. Food may enhance the extent of absorption for poorly soluble drugs eg, griseofulvin, reduce it for drugs degraded in the stomach eg, penicillin g, or have little or no effect. Only a few drugs move across cellular barriers in an active way. Routes of administration other than enteral route are called parenteral routes. Recent advances in controlledrelease techniques have allowed the delivery of drugs to the colon, that is, the lower part of the gastrointestinal tract, following oral administration, and this has raised the general interest in colonic drug absorption. Absorption pharmacokinetics an overview sciencedirect. Absorption is used to described the journey of a drug travelling from the site of administration to site of action successfully describing absorption involves several steps. Pdf there is an increasing appreciation of the role that transport proteins play in the absorption. Smart drugs and nutrients pdf printer floorball referee. Such drugs can exert the pharmacological action only when they come.
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. Paterson3 asthma research council clinical pharmacology unit, department of medicine, cardiothoracic institute, london sw36hp 1 ten patients undergoing diagnostic bronchoscopy had. Correlation of drug absorption with molecular surface properties. Paterson3 asthma research council clinical pharmacology unit, department of medicine, cardiothoracic institute, london sw36hp 1 ten patients undergoing diagnostic bronchoscopy had radioisotopically labelled drugs put. Targeting receptors, transporters and site of absorption. Other pharmacokinetic issues, such as drug absorption, distribution, and storage, will then be addressed. Lipid soluble non ionized drugs are absorbed faster. Drug, meal and formulation interactions influencing drug. Greater the lipid water solubility coefficient, more is the lipid solubility of the drug and greater is the absorption. Stomach has a rich blood supply and relatively large surface area but it is not a major site for drug absorption. Pharmacokinetics the absorption, distribution, and. Absorption is a primary focus in drug development and medicinal chemistry, since the drug must be absorbed before any medicinal effects can take place. Sep 09, 2006 lecture 3 drug absorption 9 sep 2006 free download as powerpoint presentation. Pharmacokinetics basics absorption, distribution, metabolism.
The factors affecting absorption of drugs are related both to the drugs and to the body factors related to drugs. Drug absorption definition of drug absorption by medical. Jul 04, 2012 if drugs especially used in cancer have structural similarities to such agents, they are absorbed actively. Smart drugs and nutrients pdf printer download smart drugs and nutrients pdf printer read online although you can easily purchase synthesized smart drug and nootropic supplements from a variety of online retailers, i also think its a bit intriguing to consider the possibility of creating your own perfect blend of smart drugs customized to you. For drug absorption to occur, a drug must cross biologic barriers e. Evaluating strategies for oral absorption enhancement. Factors affecting drug absorption and distribution. To understand how drugs work, one must understand the concept of drug kinetics. These actions involve the processes of drug absorption into the body, distribution of that drug to various tissues, metabolism or breakdown, and excretion or elimination. For a drug to produce a therapeutic effect, it must reach to its target and it must accumulate at that site to reach to the minimum concentration required to produce the required effect. Lipid water solubility coefficient is the ratio of dissolution of drug in lipid as compared to water. A need for adme characterization in drug discovery and development jay tibbittsa, david canter b, ryan graff, alison smithb, and leslie a.
Dressman received february 20, 1996, from the department of pharmaceutics, victorian college of pharmacy, monash university. The presence of fatty foods can also lead to increased gastric emptying time, which can lead to degradation or reduced absorption of some drugs. Well absorbed, with oral bioavailability of about 70%. Drugs that affect gastric emptying eg, parasympatholytic drugs affect the absorption rate of other drugs. 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. Chart and diagram slides for powerpoint beautifully designed chart and diagram s for powerpoint with visually stunning graphics and animation effects. Mergers and acquisitions were perhaps not that relevant in the older closed economies, but in todays world their importance cannot be undermined. Due to the acidic nature of the stomach mucosa and the presence of enzymes such as pepsin, drugs may be degraded before they are absorbed. Pharmacokinetics, biodistribution, and pharmacodynamics of.
In short, drug kinetics refers to the actions taken by the human body to deal with a medicine. Food, other drugs, and digestive disorders can affect drug absorption and bioavailability. Pharmacokinetic absorption, distribution, metabolism, and excretion adme parameters are today considered to have a crucial role in the selection process of oral candidate drugs for product. The colon plays a small role in absorbing drugs and many slowrelease preparations probably. If drugs especially used in cancer have structural similarities to such agents, they are absorbed actively. Data sources include ibm watson micromedex updated 10 apr 2020, cerner multum updated 6 apr 2020, wolters kluwer updated. Drugs enter directly into the systemic circulation and therefore avoid the portal blood system and avoid first pass metabolism. Absorption is the process by which drug molecules cross biological membranes. This is due to their incomplete absorption from the gastrointestinal tract. It is usually associated with oral drugs and their absorption through the git.
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