Calculation of the Rate of Absorption of Exogenous Creatinine

Dominguez, R.; Pomerene, Elizabeth

doi:10.3181/00379727-60-15130

Cited by 31 publications

(13 citation statements)

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“…For all practical purposes, the formation and release of creatinine is determined by the muscular mass and hence remains essentially constant in the same individual, although recent data indicate that in the steady state, creatine is readily converted to creatinine upon cooking and may affect creatinine output [51a]. Intravenously injected creatinine is quantitatively ex creted in urine; although a large fraction of orally ingested creatinine is recovered in the stool [24,25].…”

Section: Creatine Clearance As a Measure Of Glomerular Filtrationmentioning

confidence: 99%

“…Urinary creatinine is derived metabolically from mus cle creatine and phosphocreatine [24,25] in an irrevers ible reaction [25] except under conditions of alkaline pH and heat [51a]. For all practical purposes, the formation and release of creatinine is determined by the muscular mass and hence remains essentially constant in the same individual, although recent data indicate that in the steady state, creatine is readily converted to creatinine upon cooking and may affect creatinine output [51a].…”

Section: Creatine Clearance As a Measure Of Glomerular Filtrationmentioning

confidence: 99%

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Glomerular Filtration Rate in Children with Advanced Chronic Renal Failure: Methods of Determination and Clinical Applications

Chan

Sharpe

1982

Am J Nephrol

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The rationale, significance and pitfalls of currently available methods for the determination of glomerulai filtration rates in children with advanced chronic renal diseases are reviewed. Normal renal clearances in infants and children from birth to adulthood are presented. Methods of serial measurements of renal function, especially by the reciprocals of serum creatinine concentrations, are evaluated. They are applied clinically to monitor the effectiveness of conservative and new modalities of treatment, such as dietary supplementation with essential amino acids plus their keto analogues, and to determine that 1, 25-dihydroxyvitamin-D₃ treatment of renal osteodystrophy does not accelerate the deterioration of renal function in children with chronic renal insufficiency.

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Section: Creatine Clearance As a Measure Of Glomerular Filtrationmentioning

confidence: 99%

Section: Creatine Clearance As a Measure Of Glomerular Filtrationmentioning

confidence: 99%

Glomerular Filtration Rate in Children with Advanced Chronic Renal Failure: Methods of Determination and Clinical Applications

Chan

Sharpe

1982

Am J Nephrol

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“…Various methods for estimating the rate constants in the first order reactions involved have been described in the literature. Dominguez & Pomerene (1945), using a model not specifying the absorption process, determined the rate constant for elimination from that part of the experimental curve where absorption has become negligible, and calculated the absorption rate from the fitted curves for blood level and excretion rate as found by urine determinations. Nelson (1960), using a similar model calculated the absorption rate from urine values only, while Wiegand & Taylor (1960) determined the rate constant for the sustained-release process from in vitro experiments.…”

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confidence: 99%

Kinetics of Serum Aminosalicylic Acid Levels

Engberg-Pedersen

Mørch

Tybring

1964

British Journal of Pharmacology and Chemotherapy

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A mathematical model, involving three consecutive first order reactions, has been applied to already existing experimental material in order to explain the hourly variation in serum levels obtained after administration of varying repeated doses of different preparations of p-aminosalicylic acid to human volunteers. The model closely agrees with the experimental data for all the orally administered preparations concerned, and the differences in blood levels for different preparations can be explained in terms of the values attributed to the parameters involved in the model.The same model adequately describes the elimination of aminosalicylic acid from the blood after a single intravenous infusion provided that the initial blood level attained does not exceed about 11 mg/100 ml., but fails at higher values. In the latter instance a second order model gives a good fit to the experimental curves. The increase in serum levels found experimentally for the same subjects during the first weeks of prolonged treatment with phenyl-p-aminosalicylate corresponds to a change in the values of the parameters for the elimination from the blood only.First order reactions have previously been proposed to explain the elimination of various drugs from the blood stream, and a combination of two consecutive first order processes has been used to account for the absorption into and subsequent elimination from the blood of orally administered preparations. Wiegand & Taylor (1960) have developed formulae for the combination of three consecutive first order reactions in order to explain the effects of sustained-release tablets.Various methods for estimating the rate constants in the first order reactions involved have been described in the literature. Dominguez & Pomerene (1945), using a model not specifying the absorption process, determined the rate constant for elimination from that part of the experimental curve where absorption has become negligible, and calculated the absorption rate from the fitted curves for blood level and excretion rate as found by urine determinations. Nelson (1960), using a similar model calculated the absorption rate from urine values only, while Wiegand & Taylor (1960) determined the rate constant for the sustained-release process from in vitro experiments. METHODSIn the present study none of these methods were applicable because the already existing experimental material did not include urinary determinations or in vitro experiments for the sustained-release process; moreover the scheme involving three doses per day prevented the elimination process from becoming dominant for a sufficiently long time to obtain a reasonably good estimate of the elimination rate constant. Therefore, it was decided to obtain direct estimates of the three rate constants and the apparent distribution volume by non-

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“…Creatinine absorption, moreover, is relatively complete, amounting to approximately 75% of the amount administered orally. Nor does it appear to be metabolized in the organism, for 96 per cent of intravenously administered creatinine has been recovered in the urine (DOMINGUEZ & POMERENE 1945). Finally, since creatinine can be determined with satisfactory accuracy in blood and urine, it is welt suited for absorption studies.…”

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confidence: 99%