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level: Level 1 of wk12 chap10(5) PROTEIN BINDING.ppt

Questions and Answers List

level questions: Level 1 of wk12 chap10(5) PROTEIN BINDING.ppt

Question	Answer
Drug distribution throughout the body occurs primarily via the 1 __ where drug molecules diffuse through a network of fine capillaries to the tissue spaces filled with 2 __ and further across the cell membrane into the 3 __	1 circulatory system, 2 interstitial fluid (ECF), 3 cell cytoplasm.(Diffusional)
1 generally diffuse across cell membranes more easily than highly polar or water-soluble drugs. 2 If a drug is bound to a plasma protein such as __, it forms a drug-protein complex that is too large to diffuse easily across the capillary membranes	1 Lipid-soluble drugs 2 albumin
2 Methods by which drugs traverse capillary membranes	1 Passive diffusion 2 Hydrostatic pressure
is the main process by which MOST DRUGS CROSS CELL MEMBRANES DESCRIBED BY FICK’S LAW OF DIFFUSION in which drug molecules move from an area of HIGH concentration TO an area of LOW concentration.	Passive diffusion
represents the PRESSURE GRADIENT BETWEEN the ARTERIAL END OF THE CAPILLARIES entering the tissue and THE VENOUS CAPILLARIES leaving the tissue. RESPONSIBLE FOR PENETRATING WATER-SOLUBLE DRUGS into spaces between endothelial cells and possibly into LYMPH. BLOOD FLOW-INITIATED MIXING, as distinguished from diffusion	Hydrostatic pressure
PROCESS OF DRUG TRANSFER FROM CAPILLARY INTO THE TISSUE FLUID is SPONTANEOUS and TEMPERATURE DEPENDENT.	Diffusion
DIFFUSION MECHANISMS	1 Perfusion or Flow-Limited 2 Diffusion or Permeability limited
process when DRUG DIFFUSES RAPIDLY ACROSS THE MEMBRANE with BLOOD FLOW AS THE RATE-LIMITING STEP in the distribution of drug	Perfusion or Flow-Limited Ex. In CHF, has low cardiac output? impaired blood flow, reduced renal clearance thru decreased filtration pressure & blood flow.
drug distribution is LIMITED by SLOW DIFFUSION OF DRUG ACROSS THE TISSUE MEMBRANE	Diffusion or Permeability limited Ex. Increased Vd in disease conditions that causes inflam & increased capillary permeability (Edema)
Factors that alter osmotic pressure balance	1 CHANGES IN ALBUMIN, or blood loss 2 CHANGES IN ELECTROLYTE LEVELS in renal & hepatic disease These results in net flow of plasma water into the interstitial space (EDEMA) Thus increase extravascular drug distribution in some disease state.
Drug Accumulation The accumulation of drug into tissues is dependent on both the __	1 BLOOD FLOW and 2 AFFINITY OF THE DRUG FOR THE TISSUE.
Drug Accumulation 1 Drug uptake into a tissue is generally __ 2 The drug concentration in a tissue with LOW CAPACITY equilibrates rapidly with the __ and then declines rapidly as the drug is eliminated from the body. 3 In contrast, drugs with HIGH TISSUE AFFINITY tend to __	. 1 REVERSIBLE. 2 plasma drug concentration 3 ACCUMULATE or concentrate in the tissue.
Drugs may accumulate in tissues by other processes.	1 by BINDING TO PROTEINS or other macromolecules in a tissue. 2 may COMPLEX WITH MELANIN in the skin and eye 3 may FORM AN INSOLUBLE CHELATE with calcium.
It describes the ABILITY OF PROTEINS TO FORM BONDS with other substances, and most commonly refers to the bonding of drugs to these molecules in blood plasma, red blood cells, other components of the blood, and to tissue membranes.	Protein-binding
1 A DRUG'S EFFICIENCY may be AFFECTED by the degree to which it binds to the __within blood plasma. 2 The less bound a drug is, the __ it can traverse cell membranes or diffuse	1 proteins 2 more efficiently
1 The bound drug is kept in the blood stream while the UNBOUND COMPONENT may be __, making it the ACTIVE PART.	1 METABOLIZED or EXCRETED So, if a drug is 95% bound to a binding protein and 5% is free, that means that 5% is active in the system and causing pharmacological effects.