Advanced Search

Home > Journals > The Quarterly Journal of Nuclear Medicine and Molecular Imaging > Past Issues > The Quarterly Journal of Nuclear Medicine 2002 September;46(3) > The Quarterly Journal of Nuclear Medicine 2002 September;46(3):181-94

ISSUES AND ARTICLES   MOST READ   eTOC

CURRENT ISSUETHE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING

A Journal on Nuclear Medicine and Molecular Imaging

A Journal on Nuclear Medicine and Molecular Imaging
Affiliated to the Society of Radiopharmaceutical Sciences and to the International Research Group of Immunoscintigraphy
Indexed/Abstracted in: Current Contents/Clinical Medicine, EMBASE, PubMed/MEDLINE, Science Citation Index (SciSearch), Scopus
Impact Factor 2,413

Frequency: Quarterly

ISSN 1824-4785

Online ISSN 1827-1936

 

The Quarterly Journal of Nuclear Medicine 2002 September;46(3):181-94

NOVEL METHODS OF ALTERING PHARMACOKINETICS IN RADIOPHARMACEUTICAL DESIGN
Guest Editor: Hnatowich D. 

Analysis of renal handling of radiopharmaceuticals

Trejtnar F., Laznicek M.

Faculty of Phar­macy, ­Charles Uni­ver­sity Hradec Kra­love, ­Czech ­Republic

Renal excre­tion is the pref­er­able elim­i­na­tion ­pathway of radio­phar­ma­ceu­ti­cals and/or ­their metab­olites ­from the ­body. The mech­a­nisms of ­renal excre­tion ­involve glo­mer­ular fil­tra­tion, ­tubular secre­tion, ­tubular reab­sorp­tion, and ­kidney metab­olism. Radio­phar­ma­ceu­ti­cals of a molec­ular ­weight of up to 60 kDa are ultra­fil­trated in the glom­e­ruli at a ­rate depen­dent on ­their pro­tein ­binding (the ­rate of glo­mer­ular fil­tra­tion is a ­product of glo­mer­ular fil­tra­tion ­rate and ­free frac­tion of the ­agent in ­plasma). Exclu­sive excre­tion by ­this ­route is typ­ical for ­many che­lates ­such us 99mTc-­DTPA (dieth­y­len­e­tri­a­min­e­pen­taa­cetic ­acid). ­Some ­other radio­phar­ma­ceu­ti­cals are ­excreted in the ­renal ­tubuli ­into the ­tubular ­fluid by car­rier-medi­ated and ­active pro­cesses ­involving dif­ferent trans­port ­systems. Exam­ples are ­ortho-iod­o­hip­pu­rate and 99mTc-MAG-3 (mer­cap­toa­ce­tyl­trig­ly­cine). ­Tubular reab­sorp­tion ­involves ­either pas­sive dif­fu­sion of ­lipid-sol­uble radio­phar­ma­ceu­ti­cals ­from the glo­mer­ular fil­trate ­back ­into ­blood or ­active, car­rier-medi­ated pro­cess. ­Kidney metab­olism and con­se­quent ­renal ­uptake of the cat­a­bo­lites is of an out­standing impor­tance for pos­sible ther­a­peutic appli­ca­tions of radio­lab­eled anti­body frag­ments and pep­tides. ­These ­agents are par­tially reab­sorbed ­from the ultra­fil­trate by the ­cells of the ­renal prox­imal ­tubules by ­means of pin­o­cy­tosis and sub­se­quently ­degraded in the lyso­somes. It ­limits ­their ther­a­peutic use due to the poten­tial radi­a­tion neph­ro­tox­icity. For the anal­ysis of elim­i­na­tion mech­a­nisms of radio­phar­ma­ceu­ti­cals in the ­kidney, dif­ferent ­approaches at var­ious experi­mental ­levels (the ­kidney per­fu­sion tech­nique, iso­lated, func­tion­ally ­intact ­renal ­tubules, and iso­lated mem­branes) ­could be suc­cess­fully ­employed.

language: English


FULL TEXT  REPRINTS

top of page