🏷️ LIMITED TIME OFFER: GET 20% OFF GRADE+ YEARLY SUBSCRIPTION →

HomeClass Notes1,200,000AU40,000

PCOL2605 Lecture Notes - Lecture 4: Lipid Bilayer, Pinocytosis, Intrinsic Factor

77 views12 pages

23 Oct 2018

School

University of Sydney

Department

Course

Professor

Brooke Storey Lewis

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Absorption; movement of a drug from its site of admin into the body. Distribution; movement of drug out of the blood into the tissues and site of action. Metabolism; or breakdown of drug (mainly in liver but also other tissues. Excretion; of a drug and metabolites (in urine, faeces and other matrices) Barrier through which drugs must pass; e. g. from stomach into blood and distribution to tissues. Cell membrane basically consists of phospholipid bilayer. Phospholipid molecule has a hydrophilic head and a hydrophobic (lipophilic) tail. Also contains cholesterol (for strength and consistency of membrane) Within larger aqueous compartments (e. g. interstitial space) Across membranes via pores (small molecules only) Passive (simple) diffusion is movement across cell membrane without the need for energy expenditure. Lipid soluble drugs dissolve in cell membrane and diffuse across the membrane. Water soluble drugs cross cell membrane through aqueous channels in membrane (small molecules)

Related Documents

PHAR 100 Lecture Notes - Lecture 5: Biotransformation, Lipid Bilayer, Pinocytosis

emeraldwalrus65

NURS 116 Lecture 2: Pharmocokinetics (PK)

ultramarineprairie-dog808

NUR 326- Final Exam Guide - Comprehensive Notes for the exam ( 65 pages long!)

Related Questions

Please help with questions 1-5. Thank you!

46 Experiment 8: Determination of Kow the lipid and As stated, for a drug to pass from the small intestine to the bloodstream, it must cross bilayer, move through the aqueous cell, cross the other side of the spherical lipid bilayer. then exit into the aqueous blood stream. The drug must thus show some affinity tor aqueous and organic phases The partition coefficient (P) is an equilibrium constant for a process in which a solute is the distribution of partitioned between two phases. In medicine, this value is useful in estimating drugs within the body. Hydrophobic drugs with high partition coefficients are preferentially distributed to hydrophobic areas (such as fat tissues) while hydrophilic drugs with low partition coefficients prefer hydrophilic regions (such as blood serum). Partition coefficients can also be useful in predicting metabolic stability, as extremely hydrophobic drugs are often metabolized to more polar compounds to increase their water solubility for more effective urinary excretion. Given the complexity of cells, it is very difficult to directly measure partitioning of a compound between the aqueous and lipid components of a cell, particularly if evaluating the tens of thousands of compounds that might be investigated in a new drug development program. Hence, a simpler model system can be used in which 1-octanol serves as a mimic of the amphiphilic membrane lipid molecules, and water as the aqueous component. (In some cases, buffer solutions at particular pH values are used to better mimic cellular conditions). The partition coefficient P is often denoted as Kom, which specifically describes the degree to which a drug prefers octanol (o) or water (w). Knowing the Kow of a drug is crucial to predicting its pharmokinetic properties (i.e what the body will do to the drug). For convenience, a logKo value is more typically reported than Kow itself. Drugloctanol ow[Drug water In this experiment, we will investigate the ability of several drugs to move between aqueous and organic phases. These drugs are sulfanilamide (an antibiotic), phenacetin (an analgesic), acetaminophen (an analgesic), and caffeine (a stimulant) (Figure 3). We will determine logK by measuring the equilibrium concentrations of the drug in the aqueous and organic phases using UV-Vis spectroscopy NH2 HN Sulfanilamide Phenacetin Caffeine Figure 3: Structures of the drugs for which we will determine a partition coefficient

I need help with pre lab 3 and 4 please :)

Experiment 8: Determination of k 45 Exp 8: Determination of Logkow Values for Four Drugs Objectives . Discover how compound polarity affects absorptiorn e Perform extractions Calculate and compare partition coefficients (Olog Kp)of four different pharmaceutical Intreduction Pharmaceutical drug design involves creating a molecule that will target a general region or site and have a therapeutic effect on the patient. Such properties depend on the drug's structure as well as its affinity for different phases in the body. When orally ingested, a drug moves from the stomach into the small intestine. From there, a drug must pass through a layer of cells before it can enter the bloodstrcam (this process is called absorption) and be distributed throughout the body. This requires crossing through largely non-polar cell membrane twice, first to enter the cell from the intestine side and then to exit the cell for entry into the bloodstream Solubility properties have a large influence on the drug's ability to navigate this trek. The drug must be polar enough to convey water solubility so that it does not precipitate out in the water solution that is well, us. For it to be absorbed into the bloodstream, however, a drug mast be non-polar enough to pass through a non-polar lipid bilayer that forms the membranes of cells. A lipid is an organic molecule that can be extracted from living tissues using non-polar organic solvents. A lipid bilayer is a thin membrane made of two lipid layers; the bilayer forms a spherical non-polar barrier separating the inside of a cell from the outside of a cell. The types of lipids that are found in cell membeanes (most commonly phospholipids (Figure 1)) are amphiphilic molecules consisting of hydrophobic ("water-fearing") and hydrophilic ("water-loving") parts. In lipid bilayers, these amphiphilic molecules arrange themselves such that the inside of the bilayer is hydrophobic while the outside (which faces the aqucous intracellular and extracellular environments) is hydrophilic (Figure 2) Figure 1: A phospholipid containing a hydrophilic head and two hydrophobic tails Figure 2: A cartoon representation ofa layer of cells separating the intestne from the bloodstream. An orally-ingested drug must pass through a cell to enter the Noodstream, cncountering both hydrophobic and hydrophilic environments in the process. Diffusion of Drug

I need help with the pre lab questions:)

Experiment 8: Determination of k 45 Exp 8: Determination of Logkow Values for Four Drugs Objectives . Discover how compound polarity affects absorptiorn e Perform extractions Calculate and compare partition coefficients (Olog Kp)of four different pharmaceutical Intreduction Pharmaceutical drug design involves creating a molecule that will target a general region or site and have a therapeutic effect on the patient. Such properties depend on the drug's structure as well as its affinity for different phases in the body. When orally ingested, a drug moves from the stomach into the small intestine. From there, a drug must pass through a layer of cells before it can enter the bloodstrcam (this process is called absorption) and be distributed throughout the body. This requires crossing through largely non-polar cell membrane twice, first to enter the cell from the intestine side and then to exit the cell for entry into the bloodstream Solubility properties have a large influence on the drug's ability to navigate this trek. The drug must be polar enough to convey water solubility so that it does not precipitate out in the water solution that is well, us. For it to be absorbed into the bloodstream, however, a drug mast be non-polar enough to pass through a non-polar lipid bilayer that forms the membranes of cells. A lipid is an organic molecule that can be extracted from living tissues using non-polar organic solvents. A lipid bilayer is a thin membrane made of two lipid layers; the bilayer forms a spherical non-polar barrier separating the inside of a cell from the outside of a cell. The types of lipids that are found in cell membeanes (most commonly phospholipids (Figure 1)) are amphiphilic molecules consisting of hydrophobic ("water-fearing") and hydrophilic ("water-loving") parts. In lipid bilayers, these amphiphilic molecules arrange themselves such that the inside of the bilayer is hydrophobic while the outside (which faces the aqucous intracellular and extracellular environments) is hydrophilic (Figure 2) Figure 1: A phospholipid containing a hydrophilic head and two hydrophobic tails Figure 2: A cartoon representation ofa layer of cells separating the intestne from the bloodstream. An orally-ingested drug must pass through a cell to enter the Noodstream, cncountering both hydrophobic and hydrophilic environments in the process. Diffusion of Drug