Radionuclide Examination of the Kidneys
Michael Ljungberg in Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Clearance can be measured as plasma clearance, which is the volume of plasma cleared of the substance per unit time (not necessarily just by the kidneys), or renal clearance, which is the volume of plasma cleared per unit time by the kidneys (or cleared of the substance taken up by the kidneys). Urinary clearance is the volume of plasma cleared of the substance that is excreted into the urine. With the substances used to measure GFR, plasma, renal, and urinary clearances are equal because they are excreted exclusively by glomerular filtration in the kidneys and ultimately appear in the urine. The term plasma (instead of blood) clearance is used because the concentration of the test substance is usually measured in plasma. Whole blood (plasma plus blood cells) clearance is used less frequently. It can be the same as plasma clearance (with the substances entering blood cells) or greater than that, with the substances confined to plasma [19].
Cefaclor, Cefprozil, and Loracarbef
M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson in Kucers’ The Use of Antibiotics, 2017
Most of the absorbed cefprozil is eliminated via the kidney. Overall, about 61% of the administered dose is excreted in the urine as the active unchanged drug. The renal clearance is about 200 ml/minute. This suggests that cefprozil is excreted by both glomerular filtration and tubular secretion. Mean concentrations of the drug in urine are highest during the first 4 hours after the dose and range from 175 to 658 μg/ml after doses of 250 mg and 1 g, respectively (Barbhaiya et al., 1990a; Barbhaiya et al., 1990b; Barriere, 1992; Lode et al., 1992). More cefprozil is absorbed (94% of dose) than is excreted in the urine (61% of dose). In patients who have hepatic disease, the kinetic disposition of cefprozil was only minimally altered. The kidney has the primary role in elimination of this drug (Barriere, 1992). No metabolites have been detected in urine (Lode et al., 1992).
Renal Function in Hyperthermia
Leopold J. Anghileri, Jacques Robert in Hyperthermia in Cancer Treatment, 2019
Several investigators have observed a decrease in the effective renal plasma flow (ERPF) as measured by the renal clearance of para-aminohippuric acid (PAH) during hyperthermia.1,36,47,70,76,82 The glomerular filtration rate (GFR), as determined by the renal clearance of inulin or creatinine, is also diminished.12,35,36,47,62,70,82 Although the clearance of creatinine from blood is diminished during hyperthermia, the amount of creatinine in the urine may be increased due to enhanced creatinine release into blood from enhanced muscle metabolism. In this regard Parks and Smith have observed an increased urinary excretion of creatinine67 and Bull et al.12 have found increased plasma creatinine levels in patients undergoing therapeutic hyperthermia. By field et al.15 have reviewed clearance measurements reported in the older literature.
Drug metabolic stability in early drug discovery to develop potential lead compounds
Published in Drug Metabolism Reviews, 2021
Siva Nageswara Rao Gajula, Nimisha Nadimpalli, Rajesh Sonti
Predicting in vivo pharmacokinetic data from the in vitro drug metabolism data is of great interest in preclinical studies. Data acquired from the in vitro metabolism helps in selecting potent leads for further development. Knowledge of drug clearance provides information about the dose required to maintain steady-state plasma concentration and drug disposition description (Chiou 1982; Bardal et al. 2011). Clearance is the volume of plasma from which the drug is removed per unit of time (Chiou 1982; Bardal et al. 2011). Plasma clearance (or total systemic clearance) can be characterized by all the metabolizing and eliminating organs involved in the drug clearance (Wilkinson and Shand 1975; Dowd 2017). These organs primarily include the liver (hepatic clearance) and kidney (renal clearance). Hepatic clearance is the liver's ability to remove the drug from the blood and is related to two variables: hepatic blood flow rate and intrinsic hepatic clearance (Wilkinson and Shand 1975). On the other hand, renal clearance is the volume of blood or plasma completely cleared off the drug by the kidneys per unit time (Tucker 1981).
Effect of quercetin on the pharmacokinetics of selexipag and its active metabolite in beagles
Published in Pharmaceutical Biology, 2022
Shun-bin Luo, Er-min Gu, Yu-ao Chen, Shi-chen Zhou, Chen Fan, Ren-ai Xu
The pharmacokinetic parameters of selexipag and ACT-333679 after orally administered selexipag with and without quercetin pre-treatment in beagles were calculated by the DAS 2.0 software (Shanghai University of Traditional Chinese Medicine, China) in non-compartmental analysis. Cmax was the maximum observed plasma concentration, Tmax was the time to reach the maximum observed plasma concentration. AUC0–t and AUC0–∞ were the area under the concentration-time curve to the last time point and area to infinity, respectively. The apparent volume of distribution (Vd) refers to the ratio of the drug dose to blood concentration after a drug has reached dynamic equilibrium in the body. Plasma clearance (CL) is the total clearance rate of drugs in the liver and kidney, that is, how much volume of plasma is cleared of drugs per unit time.
Effect of compromised liver function and acute kidney injury on the pharmacokinetics of thymoquinone in a rat model
Published in Xenobiotica, 2020
Khalid M. Alkharfy, Fahad A. Ali, Mohammad A. Alkharfy, Basit L. Jan, Mohammad Raish, Saeed Alqahtani, Ajaz Ahmad
Glue and coworkers determined the effect of renal damage on single-dose felbamate pharmacokinetics. The investigators presented that, in comparison to controls, felbamate clearance was reduced although T1/2 and AUC0–∞ values elevated in subjects with kidney dysfunction. The extent of these variations was co-related with the degree of kidney dysfunction (Glue et al., 2003). Brockmoller and coworkers studied probable alterations in the levetiracetam pharmacokinetics in patients with cirrhosis of liver. The researchers found that, in patients with severe liver cirrhosis, the drug clearance was diminished by 43% and plasma T1/2 was significantly prolonged as compared with normal subjects. The investigators measured levetiracetam renal clearance and found that it was adequately reduced. Moreover, they reported that the decrease in renal clearance was correlated with the worsening in renal function (Brockmoller et al., 2005).
Related Knowledge Centers
- Excretion
- Hemodialysis
- Nephron
- Peritubular Capillaries
- Physiology
- Pharmacokinetics
- Blood Plasma
- Pharmacology
- Glomerular Filtration Rate
- Kidney