Absorption, Distribution and Excretion
EXCRETION OF P-AMINOHIPPURIC ACID DURING SWEATING IN MAN: SWEAT/PLASMA RATIO: 0.02; PKA= 3.8. /FROM TABLE/
1.4% OF DOSE OF P-AMINOHIPPURIC ACID IS EXCRETED IN BILE OF RAT AFTER 3 HR. /FROM TABLE/
BILIARY EXCRETION OF 4-AMINOHIPPURIC ACID IN DIFFERENT SPECIES: % OF DOSE EXCRETED IN 3 HR: RAT 3.3; GUINEA PIG 6.7; RABBIT 3.0; DOG 3.4; CAT 0.7; HEN 0.5. /FROM TABLE/
SERUM EXTRACTION RATIO...FROM DOG RENAL CORTEX.../IS/ 0.74 FOR P-AMINOHIPPURIC ACID...
For more Absorption, Distribution and Excretion (Complete) data for P-AMINOHIPPURIC ACID (8 total), please visit the HSDB record page.

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Metabolism / Metabolites
YIELDS P-ACETAMIDOHIPPURIC ACID IN PIGS: GYRD-HANSEN, N & F RASMUSSEN, ACTA PHYSIOL SCAND, 80, 249 (1970). /FROM TABLE/
ORALLY ADMIN PAH GAVE RISE TO P-AMINOBENZOIC ACID, P-AMINOHIPPURIC ACID, P-ACETYLAMINOBENZOIC ACID, P-ACETYLAMINOHIPPURIC ACID, & P-ACETYLAMINOBENZOYLGLUCURONIC ACID IN URINE. WHEN ADMIN IV, ONLY P-ACETYLAMINOHIPPURIC ACID & UNCHANGED P-AMINOHIPPURIC ACID WERE EXCRETED.

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Biological Half-Life
The biologic half-life of PAH in patients with normal renal function is 24 minutes.

Interactions
...DRUGS THAT SHARE A COMMON EXCRETORY PATHWAY WITH PAH (EG, PENICILLIN), THOSE THAT INHIBIT RENAL TUBULAR TRANSPORT (EG, PROBENECID), OR THOSE THAT HAVE A URICOSURIC EFFECT (EG, SALICYLATES) CAN INTERFERE WITH PAH CLEARANCE.
RENAL EXCRETION OF HALOFENATE IS...DIMINISHED BY...P-AMINOHIPPURATE /IN CHIMPANZEES/ @ ALL OBSERVED URINARY PH VALUES.
Patients receiving drugs that employ the same tubular excretory mechanism as PAH may exhibit mutually decreased excretion of the drugs because of competitive inhibition. Agents that share a common excretory mechanism include diuretics, iodopyracet, penicillin, phenolsulfonphthalein, probenecid, and saliclyates.
Agents that interfere with calorimetric analytical procedures, including procaine, sulfonamides, and thiazolsulfone, prevent accurate urinary measurements of PAH.

P-aminohippuric acid is an N-acylglycine that is the 4-amino derivative of hippuric acid; used as a diagnostic agent in the measurement of renal plasma flow. It has a role as a Daphnia magna metabolite. It is a conjugate acid of a p-aminohippurate.
Aminohippuric acid has been reported in Brassica napus and Daphnia magna with data available.
Aminohippurate Sodium is sodium salt of aminohippuric acid. Aminohippurate sodium is used as a non-toxic diagnostic tool to measure effective renal plasma flow. At low plasma concentration this agent is filtered by the glomeruli and almost completely cleared from the renal blood stream by active tubular secretion in a single transit through the kidney. Its clearance corresponds to the renal plasma blood flow. Aminohippurate sodium is also used to measure functional capacity of the renal tubular secretory mechanism. This is achieved by elevating the drug plasma concentration to levels sufficient to saturate the maximal secretion capacity of the tubular cells.
The glycine amide of 4-aminobenzoic acid. Its sodium salt is used as a diagnostic aid to measure effective renal plasma flow (ERPF) and excretory capacity.

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Drug Indication
Used to measure effective renal plasma flow (ERPF) and to determine the functional capacity of the tubular excretory mechanism.

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Mechanism of Action
Aminohippurate is filtered by the renal glomeruli and secreted into the urine by the proximal tubules. By measuring the amount of drug in the urine it is possible to determine functional capacity and effective renal plasma flow.
P-AMINOHIPPURATE (PAH) IS PROTOTYPE FOR AN AGENT EXCRETED BY ORGANIC ACID TRANSPORT SYSTEM...LOCATED IN PROXIMAL CONVOLUTED TUBULES...PROTEIN-BOUND TOXICANTS ARE FULLY AVAIL FOR ACTIVE TRANSPORT. /PROCESS HAS/...ALL CHARACTERISTICS OF ACTIVE TRANSPORT SYSTEM; THEREFORE VARIOUS COMPD COMPETE WITH ONE ANOTHER FOR SECRETION.

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Therapeutic Uses
Aminohippurate sodium (PAH) is used in plasma concentrations of 10-20 ug/ml to estimate effective renal plasma flow (ERPF) which is an index of renal function. In these low plasma concentrations, PAH is extracted almost completely from the plasma with each passage through functional renal tissue, and the value obtained for PAH clearance is accepted as being numerically equal to the ERPF. In plasma concentration of 400-600 ug/ml, PAH is used in conjunction with glomerular filtration rate (GFR) measurements to estimate the functional capacity of the renal tubular secretory mechanism. Since PAH is excreted both by tubular secretion and glomerular filtration, tubular transport capacity can be determined by comparing PAH excretion with values for GFR obtained by inulin clearance. Although this test may be the best quantitative measure of functioning nephron mass, its complexity prevents its widespread use. PAH clearance tests are more accurate but also more complex than phenolsulfonphthalein excretion tests for evaluation of renal blood flow. In most clinical situations, simpler (although less precise) methods of renal function evaluation are used.
MEDICATION: DIAGNOSTIC AID (RENAL FUNCTION DETERMINATION) /SRP: NOT COMMONLY USED IN RENAL FUNCTION TEST/

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Drug Warnings
AT PLASMA LEVELS USED TO MEASURE MAX TUBULAR SECRETION, PAH SIGNIFICANTLY INCR SODIUM, POTASSIUM, & PHOSPHORUS CLEARANCE IN HUMAN VOLUNTEERS. AT LEVELS USED TO MEASURE RENAL PLASMA FLOW, IT INCREASED ONLY SODIUM CLEARANCE.
MANY WORKERS ROUTINELY USE CLEARANCE OF PAH AS AN ESTIMATE OF RENAL PLASMA FLOW. ...PRACTICE /WAS NOT RECOMMENDED/ FOR 3 REASONS: 1) RENAL EXTRACTION OF PAH IS...VARIABLE EVEN WHEN PLASMA CONCN IS LOW, 2) PAH IS REABSORBED, 3) PAH MAY SUPPRESS RENAL TRANSPORT OF TEST DRUG IF IT IS A WEAK ORGANIC ACID.
WHEN PLASMA CONCN OF PAH ARE RAISED RAPIDLY, PATIENTS MAY EXPERIENCE NAUSEA OR VOMITING & A SENSATION OF SUDDEN WARMTH, SYMPTOMS THAT CAN BE AVOIDED BY INFUSING DRUG MORE SLOWLY.
Adverse reactions which have been reported in association with the administration of aminohippurate sodium (PAH) include nausea, vomiting, cramps, vasomotor disturbances, flushing, tingling, a sensation of warmth, and the desire to defecate or urinate during or shortly after administration of the drug.
PAH must be administered with caution in patients with low cardiac reserve, since a rapid increase in plasma volume may precipitate congestive heart failure. The large dose required to achieve the plasma concentrations necessary for the determination of the maximum tubular secretion should be administered slowly and with caution, and the patient should be continuously observed for any adverse reactions. PAH is contraindicated in patients with known hypersensitivity to the drug or any ingredient in the formulation.

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Pharmacodynamics
Aminohippurate (p-aminohippuric acid, PAH, PAHA) is the glycine amide of p-aminobenzoic acid. It is filtered by the glomeruli and is actively secreted by the proximal tubules. At low plasma concentrations (1.0 to 2.0 mg/100 mL), an average of 90 percent of aminohippurate is cleared by the kidneys from the renal blood stream in a single circulation. It is ideally suited for measurement of ERPF since it has a high clearance, is essentially nontoxic at the plasma concentrations reached with recommended doses, and its analytical determination is relatively simple and accurate. Aminohippurate is also used to measure the functional capacity of the renal tubular secretory mechanism or transport maximum (Tm_PAH). This is accomplished by elevating the plasma concentration to levels (40-60 mg/100 mL) sufficient to saturate the maximal capacity of the tubular cells to secrete aminohippurate. Inulin clearance is generally measured during Tm_PAH determinations since glomerular filtration rate (GFR) must be known before calculations of secretory Tm measurements can be done.

C9H10N2O3

194.1873

216.051

94-16-6

2148

NEEDLES FROM HOT WATER
PRISMS FROM WATER
WHITE, CRYSTALLINE POWDER

517.2ºC at 760 mmHg

123-125°C

266.6ºC

-0.9

3

4

3

14

222

0

[Na].O=C(CNC(C1C=CC(N)=CC=1)=O)O

HSMNQINEKMPTIC-UHFFFAOYSA-N

InChI=1S/C9H10N2O3/c10-7-3-1-6(2-4-7)9(14)11-5-8(12)13/h1-4H,5,10H2,(H,11,14)(H,12,13)

2-[(4-aminobenzoyl)amino]acetic acid

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

H2O : ~100 mg/mL (~462.60 mM)
DMSO : ≥ 46 mg/mL (~212.80 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (11.56 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (11.56 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (11.56 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 100 mg/mL (462.60 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)