Request pdf factors affecting drug absorption and distribution the pharmacokinetic properties of a drug comprise the relationship between its absorption, distribution and inactivation. Factors affecting distribution of drug tissue permeability of drug 1. Lipid water solubility coefficient is the ratio of dissolution of drug in lipid as compared to water. Evaluation of risk factors affecting substance use among. Drug distribution to tissues clinical pharmacology. The process by which a drug reversibly leaves the blood stream and enters the interstitium extracellular fluid andor the cells or tissues. List two physiologic factors that can alter each of the processes of absorption, distribution, and excretion. Protein binding thus decreases the net transfer of drug across membranes. Explain how bioavailability can impact drug response and product selection. The factors affecting absorption of drugs are related both to the drugs and to the body factors related to drugs. Introduction to pharmacokinetics and pharmacodynamics.
With oral administration, several factors affect the absorption of a drug. Request pdf factors affecting drug absorption and distribution the pharmacokinetic properties of a drug comprise the relationship between its absorption. Distribution of a drug is not uniform throughout the body because different tissues receive the drug from plasma at different rates and to different extents. Contents of the powerpoint on volume of distribution include. Physiological properties of drug pka, lipid solubility, etc. Vasomotor responses 47 can be used to detect neuronal integrity, and can be detected by colour and temperature changes in the affected area using thermography, 26 but are less reliable signs 39 and occur at a higher level of block than sensory. The drugs are present in free or bound form and different processes or mechanisms affect their. Describe two types of drug interaction and explain how. Drug distribution once a drug enter in to the blood stream, the drug is subjected to a number of processes called as disposition processes that tend to lower the plasma concentration. Pathological and physiological factors affecting drug. Distribution networks and professionals are faced with more challenges now than ever.
Factors distinguishing important identified risks from. Drug factors lipid solubility of the drugs molecular weight of the drugs pka of drug. Factors affecting drug absorption and distribution request pdf. Drug factors lipid solubility of the drugs molecular weight of the drugs pka of drug 7.
Understanding factors affecting participation could help boost treatment coverage and sustain gains made in controlling onchocerciasis in endemic areas. Typically, distribution is much more rapid than elimination, is accomplished via the circulation, and is influenced by regional blood flow. Factors affecting response to drugs adherence to a drug regimen. The pharmacokinetic properties of a drug comprise the relationship between its absorption, distribution and inactivation. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Rate of distribution membrane permeability we have already covered some material about membrane permeability. Overview of factors affecting oral drug absorption. Hypotension and bradycardia are related to block height, but again are too nonspecific. Factors affecting drug absorption and distribution sciencedirect. Distribution of drugs dr shinde viraj ashok jr1 pharmacology. Several factors determine the distribution pattern of drug with time, including the. Understand drug safety and effectiveness like factors affecting drug action and adverse drug.
Inside the body, drugs move in the blood to different parts of the body. Greater the lipid water solubility coefficient, more is the lipid solubility of the drug and greater is the absorption. These factors may affect how the body absorbs the drug, how the body breaks down metabolizes and eliminates the drug, or what effects the drug has on the body. Compare the roles of passive diffusion and carriermediated transport in drug absorption. Pharmacists must also understand the relationship of drug dosage to therapeutic efficacy. Affinity of drug for tissue constituents plasmatissue. This animation presents 4 major factors that effect a drugs distribution in the body. Elimination which involves irreversible loss of drug from the body. Pdf overview of factors affecting oral drug absorption. There are many factors that affect a drug s distribution throughout an organism, but pascuzzo considers that the most important ones are the following. Factors affecting renal excretion of drugs include. Drug distribution in special compartments and bioavailability.
Drug distribution across the placenta is a special. Factors affecting drug distribution rate of distribution membrane permeability. List the assumptions made about drug distribution patterns in both one and twocompartment models. Distribution which involves reversible transfer of a drug between compartments. Thus, the amount and persistence of available drug at receptor sites change. The passage of drug from the gut into the blood is influenced by biologic and physicochemical factors discussed in detail. Introduction to pharmacokinetics and pharmacodynamics ashp. Effects on drug distribution only that fraction of the plasma drug concentration which is freely circulating i. Traditional oral or parenteral administration may not achieve optimum therapeutic concentrations of drug at its site of action. Organs of high perfusion, protein binding, molecular size. Factors affecting community participation in the cdti. This study is descriptive and crosssectional conducted between april and may 2016. Questionnaires can be written, printed, or digital.
For poorly perfused tissues eg, muscle, fat, distribution is very slow, especially if the tissue has a high affinity for the drug. Factors that influence drug distribution affect the rate and delivery of drugs to. The reciprocals of these rate constants give the time. Drug distribution once in the blood, drugs are simultaneously distributed throughout the body and eliminated. After a drug has entered tissues, drug distribution to the interstitial fluid is determined primarily by perfusion. Factors affecting drug absorption and distribution anaesthesia. A major factor affecting drug distribution is the physicochemical properties of the drug 3 since these. Ratio of blood flow to tissue mass sa for drug transfer to tissue 4. Lets talk about the determinants of distribution of a drug in the body. The lipid solubility of the drug is determined form its oilwater partition coefficient ko w value, whereby the increase in this value indicates the increase in percentage drug absorbed.
Understand theoritical pharmacokinetics like halflife, order of kinetics, steady state plasma concentration. Other factors affecting drug absorption and distribution. Factors affecting drug distribution through infusion by the infusion physics study group 051809 convection enhanced delivery ced is a technique used to distribute drugs inside the brain parenchyma using pressure to cause the movement of infused fluid. Drug factors ph of the media regional blood flow drug bindingprotein tissue membranes 6. The aim of this study is to detect the prevalence of substance use among tenthgrade students. These factors are harbingers of tight cash flow, scarce resources, increasing cost and. Factors influencing drug compliance in the mass drug. Further analysis of factors pertaining to distribution of the drugs such as the person who distributed the drugs, whether this person was known or familiar to the people, whether the drug distributor explained why the drugs were being given and about the side effects of the drugs, and whether the people were happy to take the drugs given by. The systemic absorption of a drug is dependent on 1 the physicochemical properties of the drug, 2 the nature of. Particle size of the drugs, proteins binding, surface area of the drug, excretion, ph, temperature, physical volume of the body etc. Ko w distribution of the drug in the organic phase octanol distribution of the drug in the aqueous phase. Author links open overlay panel shruti chillistone jonathan g. Factors effecting on drug distribution ashok kari 1, gandhu sateesh, bharatha suresh. Many factors affect the rate and pathway of metabolism of drugs, and the major influences can be subdivided into internal physiological and pathological and external exogenous factors.
How do cultural and genetic factors influence drug action. This concept is related to multicompartmentalization. Drug distribution is a subject that is covered in a branch of pharmacology called pharmacokinetics. Drug interactions clinical pharmacology merck manuals. Factors affecting pharmacokinetics of drugs medicilon inc. Start a free trial of quizlet plus by thanksgiving lock in 50% off all year try it free. The concentration of a drug attained after a single dose depends on its volume of distribution, which in turn depends on the volume of plasma and tissue and on the fractions of unbound drug in plasma and tissue. Impaired renal function may lead to a clinically significant accumulation of drugs eliminated by the kidneys, if more than 50% of the dose is normally excreted unchanged in the urine and the renal function is less than 50% of the. Because so many factors affect drug response, doctors must choose a drug appropriate for each person and must adjust the dose carefully. You may also see assessment questionnaire examples. This depends on the method that an entity will use to provide the questions to their target community. The drug distribution is usually varied, and depends on several factors such as. In addition to protein availability, other factors may affect drug absorption and distribution in the body as a whole or at specific sites within the body. Its going to be proportional to a number of things.
Factors and mechanisms for pharmacokinetic differences. Drug distribution impact factor omics international. Networks are being asked to plan a fourfold expansion and are simultaneously asked to plan for closure. Identify factors that cause interpatient variability in drug disposition and drug response. There are four factors that will influence the pharmacokinetic drugs test.
As the name implies, this is the stage when the drug is distributed to the bodys tissues. Differences in drug distribution among the tissue essentially arise as result of a number of factors. Drug distribution online pharmacology lecture lecturio. The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of. After multiple dosing, mean steadystate concentrations reflect the dose and dosage interval, clearance, and bioavailability. Conversely, many environmental factors that alter rates of drug disposition do so by affecting genetic mechanisms for example, phenobarbital induction of human hepatic antipyrine metabolism and benzpyrene induction of aryl hydrocarbon hydroxylase ahh activity in cultured human lymphocytes. Factors affecting dissolution rate divided into five classes a. Factors affecting drug distribution through infusion. 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. In pharmacokinetic interactions, a drug usually alters absorption, distribution, protein binding, metabolism, or excretion of another drug.
Factors affecting drug absorption and distribution. Patient acceptance of, response to, and compliance with, drug therapies may be influenced by religious restrictions and beliefs or cultural practices christian scientists. We have a selection of questionnaire examples in pdf which you may all download in this post. Over 90% of villagers knew that distribution of the drug was for treatment and prevention. Factors affecting drug distribution distribution of drugs throughout the body fluid is not equal. Describe situations in which routine clinical pharmacokinetic monitoring would be advantageous. The number of safety specifications per drug and the distribution of risk categories were significantly different between japan and the eu. The volume of distribution is 100 because its 200 divided by 2. The following table highlights some of these other factors. Several factors determine the distribution pattern of drug with time, including the delivery of drug to tissue.
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