Transcapillary Exchange

Renkin (17) tor analyzing transcapillary exchange in an isolated perfused hind limb preparation/ 

Although there have been few studies designed to interpret actual drug distribution results in physiological termS/ a possible approach is to administer the drug 

FIGURE 3.5 Plot of capillary permeability vs. molecular weight. (Reproduced with permission from Dedrick RL, Flessner MF. Prog Clin Biol Res 1989 288 429 8.) 

CLINICAL CONSEQUENCES OF DIFFERENT DRUG DISTRIBUTION PATTERNS 

The impact of physiological changes on drug distribution kinetics has not been studied extensively. For example, it is known that pregnancy alters the elimination kinetics of many drugs. But physiological 

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Cousineau D, Rose CP, Lamoureux D, Goresky CA. Changes in cardiac transcapillary exchange with metabolic coronary vasodilation in the intact dog. Circ Res 1983 53 719-30. 

Curry FE. (1984). Mechanics and thermodynamics of transcapillary exchange. In EM Renkin, CC Michel, eds. Handbook of Physiology, Section 2, The Cardiovascular System. Vol. IV, Microcirculation, Part 2. Bethesda, MD Am Physiol Society, pp 309-374. 

Simionescu N. Cellular aspects of transcapillary exchange. Physiol Rev 1983 63(4) 1536-1579. 

Simionescu N (1983) Cellular aspects of transcapillary exchange. Physiol Rev 63 1536-1579 Simons K, Ikonen E (1997) Functional rafts in cell membranes. Nature 387 569-572 Snoeck V, Goddeeris B, Cox E (2005) The role of enterocytes in the intestinal barrier function and antigen uptake. Microbes Infect 7 997-1004 Sugiyama Y, Kato Y (1994) Pharmacokinetic aspects of peptide delivery and targeting importance of receptor-mediated endocytosis. Drug Dev Ind Pharm 20 591-614 Takano M, Yumoto R, Murakami T (2006) Expression and function of efflux transporters in the intestine. Pharmacol Therap 109 137-161... 

Vicini, P., Bonadonna, R., Lehtovirta, M., Groop, L., and Cobelli, C., Estimation of blood flow heterogeneity in human skeletal muscle using intravascular tracer data Importance for modeling transcapillary exchange, Annals of Biomedical Engineering, Vol. 26, 1998, pp. 764-774. 

There is a long history behind attempts to analyze transcapillary exchange in terms of its blood flow and dif-fusional permeability components. Eugene Renkin appears... 

Davies DR, Bassingthwaighte JB, Kelly PJ. 1976. Transcapillary exchange of strontium and sucrose in canine tibia. J Appl Physiol 40(1) 17-22. 

Lemon GJ, Davies DR, Hughes SPF, et al. 1980. Transcapillary exchange and retention of fluoride, strontium, EDTA, sucrose, and antipyrine in bone. Calcif Tissue Int 31 173-181. 

Because lymph is formed from fluid filtered from the blood, an understanding of transcapillary exchange must be gained first. Usually pressure parameters favor filtration of fluid across the capillary wall to the interstitium (/c) according to the Starling-Landis equation ... 

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