PPARα (EC50 = 50 μM); PPARγ (IC50 = 500 μM)

Clofibrate is a PPAR agonist; its E50s for murine PPARα and PPARγ are 50 μM, approximately 500 μM, and for human PPARα and PPARγ are 55 μM, approximately 500 μM, respectively[1]. In two rat hepatoma cells treated with fatty acids (FA), clofibrate (0.5, 1, 2 mM) increases the expression of FABP1. When administered early, clofibrate significantly reduces ROS levels in FA-treated cells compared to when administered later[2].

Clofibrate (0.5%) elevates fetal serum concentrations and hepatic expression of FGF21, returning to baseline levels upon cessation of clofibrate treatment. Offspring administered with Clofibrate exhibit markedly increased expression of thermogenic genes (Ucp1, Cidea, Ppara Ppargc1a, Cpt1b) and UCP1 protein levels in response to a high-fat diet in the inguinal fat, but not in the epididymal or retroperitoneal fat (when combined with perirenal fat)[3].

In MEM/EBSS medium, cells are seeded at a density of 2.5 × 10⁴ cells/well (for WST-1, intracellular lipid droplet quantification and dichlorofluorescein (DCF) assay, 96-well plates) or 1 × 10⁵ cells/well (for Nile Red Staining, 12-well plates) and incubated overnight for adherence. The following day, fresh medium containing the fatty acid mixture oleate:palmitate (2:1) in the presence of 3% fatty acid-free bovine serum albumin is added to the cell culture medium. Fatty acid (FA) mixtures ranging from 0.5 to 3 mM are applied to cells for 24 to 48 hours at 37°C in a humidified incubator with 95% air and 5% CO₂. FABP1 levels in treated cell cultures are raised by clofibrate. After dissolving 500 μM of clofibrate in DMSO, it is added to the medium (final volume of DMSO < 0.1% v/v). Only DMSO is used to culture the control cells. One-day FA treatment, two-day FA treatment, early clofibrate intervention, and late clofibrate intervention are the four distinct cell treatments that are available[1].

C57BL/6JNarl mice, both male and female, are used in breeding. We use females whose parity ranges from 1 to 5. From breeding through parturition, pregnant females are fed either an experimental (CF) or control (C) diet. The CF diet is the C diet plus 0.5% clofibrate, while the C diet is based on an AIN-93M diet with a minor modification to include 21 kcal% fat from soybean oil. The presence of a vaginal plug (defined as pregnancy day 1) indicates the date of pregnancy. Following natural childbirth on day 19.5 ± 0.5 of pregnancy, all littermates are equally cared for by their mothers, who feed them the C diet for three weeks, adjusting the litter sizes to 8–10. Then, the babies are weaned onto a standard diet that isn't purified for four weeks, and finally, they are moved to a high-fat, butter-based daily fast for five weeks. In this investigation, only male progeny are employed, and two cohorts of progeny are identified based on the dietary habits of their mothers (CF or C). A controlled 12-hour light/dark cycle, unlimited access to food and water, and a temperature maintained at 23 ± 2°C are provided for each mouse. Weekly records are kept on body weight and feed consumption[3].

Absorption, Distribution and Excretion
Completely but slowly absorbed from the intestine. Between 95% and 99% of an oral dose of clofibrate is excreted in the urine as free and conjugated clofibric acid; thus, the absorption of clofibrate is virtually complete.
IN MAN, CLOFIBRATE IS COMPLETELY ABSORBED FROM INTESTINE & APPEARS IN PLASMA AS DEESTERIFIED P-CHLOROPHENOXYISOBUTYRIC ACID (CPIB); PEAK PLASMA CONCN OF THE ACID OCCUR WITHIN 4 HR AFTER ORAL ADMIN ... MAJOR FRACTION OF CPIB ... BOUND TO PLASMA ALBUMIN. ELIMINATION OF CPIB PROCEEDS IN 2 KINETIC PHASES, WITH SLOWER EXPONENTIAL PHASE HAVING MEAN HALF-LIFE OF NEARLY 15 HR. ESSENTIALLY ALL ACID ... EXCRETED IN URINE, ABOUT 60% AS GLUCURONIDE.
TRANSFER ACROSS THE PLACENTA AND INTO THE MILK AND A POSTNATAL INCREASE IN LIVER ALPHA-GLYCEROPHOSPHATE DEHYDROGENASE HAS BEEN REPORTED IN NEWBORN RATS WHOSE MOTHERS WERE FED CLOFIBRATE.
CLOFIBRATE IS RAPIDLY AND COMPLETELY ABSORBED AFTER ORAL ADMINISTRATION. IN MAN, CLOFIBRIC ACID, A MAJOR METABOLITE OF CLOFIBRATE, IS EXCRETED IN THE URINE IN THE FORM OF THE GLUCURONIDE CONJUGATE; THE PLASMA ELIMINATION HALF-LIFE OF CLOFIBRIC ACID RANGES BETWEEN 12-25 HOURS.
Clofibrate is readily and reportedly almost completely absorbed from the GI tract; approx 95-99% of an orally admin dose ... is excreted in urine as free and conjugated clofibric acid. The drug is rapidly hydrolyzed by serum enzymes to the free acid, clofibric acid ... . Peak plasma clofibric acid concn 4-6 hr after oral admin of a single 500-mg, 1-g, or 2-g doses of clofibrate in healthy individuals average 49-53, 89, or 151 ug/ml, respectively.
For more Absorption, Distribution and Excretion (Complete) data for CLOFIBRATE (7 total), please visit the HSDB record page.

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Metabolism / Metabolites
Hepatic and gastrointestinal: rapid de-esterification occurs in the gastrointestinal tract and/or on first-pass metabolism to produce the active form, clofibric acid (chlorophenoxy isobutyric acid [CPIB]).
IN MAN, CLOFIBRATE ... APPEARS IN PLASMA AS DEESTERIFIED PARA-CHLOROPHENOXYISOBUTYRIC ACID ... ESSENTIALLY ALL ACID ... EXCRETED IN URINE, ABOUT 60% AS GLUCURONIDE.
AN ACYL-LINKED ACID METABOLITE OF CLOFIBRATE HAS BEEN IDENTIFIED IN HUMAN URINE. THIS REPRESENTS THE FIRST ACYL-LINKED MERCAPTURATE FOUND IN MAN. AUTHORS PROPOSE THAT CLOFIBRATE ACYL GLUCURONIDE IS AN ELECTROPHILIC METABOLITE WHICH REACTS WITH SULFHYDRYL GROUPS & THEREFORE MAY BE RESPONSIBLE FOR THE HUMAN HEPATOTOXICITY OF CLOFIBRATE.
Hepatic and gastrointestinal: rapid de-esterification occurs in the gastrointestinal tract and/or on first-pass metabolism to produce the active form, clofibric acid (chlorophenoxy isobutyric acid [CPIB]).
Half Life: Half-life in normal volunteers averages 18 to 22 hours (range 14 to 35 hours) but can vary by up to 7 hours in the same subject at different times.

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Biological Half-Life
Half-life in normal volunteers averages 18 to 22 hours (range 14 to 35 hours) but can vary by up to 7 hours in the same subject at different times.
THE PLASMA ELIMINATION HALF-LIFE OF CLOFIBRIC ACID RANGES BETWEEN 12-25 HOURS.
Clofibric acid has an elimination half-life of 12-35 hr (mean 12-22 hr) in healthy adults and 29-88 hr in patients with renal failure. /Clofibric acid/

Toxicity Summary
Clofibrate increases the activity of extrahepatic lipoprotein lipase (LL), thereby increasing lipoprotein triglyceride lipolysis. Chylomicrons are degraded, VLDLs are converted to LDLs, and LDLs are converted to HDL. This is accompanied by a slight increase in secretion of lipids into the bile and ultimately the intestine. Clofibrate also inhibits the synthesis and increases the clearance of apolipoprotein B, a carrier molecule for VLDL. Also, as a fibrate, Clofibrate is an agonist of the PPAR-‘± receptor[4] in muscle, liver, and other tissues. This agonism ultimately leads to modification in gene expression resulting in increased beta-oxidation, decreased triglyceride secretion, increased HDL, increased lipoprotein lipase activity.

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Hepatotoxicity
Mild, transient serum aminotransferase elevations develop in a small proportion of patients receiving clofibrate, but values above 3 times normal occur in 2% or less. These abnormalities are usually asymptomatic and transient, resolving even with continuation of clofibrate. There have been rare reports of clinically apparent liver injury in patients on clofibrate. Onset of injury is usually after 2 to 3 months of treatment and the pattern of serum enzyme elevations can be either cholestatic or hepatocellular. Symptoms of immunoallergic hepatitis are rare as are autoantibodies. Chronic therapy with clofibrate has also been linked to an increased rate of gallstones, particularly among patients with chronic cholestatic liver disease (primary biliary cirrhosis).
Likelihood score: D (possible rare cause of clinically apparent liver injury).

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Protein Binding
Highly protein-bound (95% to 97%).

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Toxicity Data
Oral, mouse: LD₅₀ = 1220 mg/kg; Oral, rabbit: LD₅₀ = 1370 mg/kg; Oral, rat: LD₅₀ = 940 mg/kg.

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Interactions
ONE CASE REPORT HAS APPEARED DESCRIBING A PATIENT WITH TYPE-IV HYPERLIPOPROTEINEMIA CONTROLLED ON CLOFIBRATE THERAPY WHO DEVELOPED A RETURN OF ELEVATED SERUM CHOLESTEROL AND TRIGLYCERIDE AFTER TAKING AN ORAL CONTRACEPTIVE.
IT IS PROPOSED THAT FUROSEMIDE AND CLOFIBRATE MAY COMPETE FOR PLASMA ALBUMIN BINDING SITES.
Clofibrate also has been reported to increase the release of antidiuretic hormone from the posterior pituitary, block arginine-induced insulin and glucagon secretion by the pancreas, and lower fasting blood glucose concn and serum insulin concn in patients with diabetes mellitus. Clofibrate has variable effects on serum uric acid.
Clofibrate stimulates peroxisomal fatty acid oxidation, increases peroxide levels and thereby enhances ethanol oxidation by catalase. However, it would only be under such unusual circumstances that catalase would be expected to play a significant role in ethanol metabolism.
For more Interactions (Complete) data for CLOFIBRATE (15 total), please visit the HSDB record page.

[1]. The PPARs: from orphan receptors to drug discovery. J Med Chem. 2000 Feb 24;43(4):527-50.

[2]. Clofibrate Attenuates ROS Production by Lipid Overload in Cultured Rat Hepatoma Cells. J Pharm Pharm Sci. 2017;20(0):239-251.

[3]. Prenatal PPARα activation by clofibrate increases subcutaneous fat browning in male C57BL/6J mice fed a high-fat diet during adulthood. PLoS One. 2017 Nov 2;12(11):e0187507.

Therapeutic Uses
Anticholesteremic Agents; Antilipemic Agents
Clofibrate is indicated only in subjects with increased concentrations of VLDL and IDL (such as patients with familial type-III hyperlipoproteinemia) who have failed to respond adequately to gemfibrozil or nicotinic acid. Because clofibrate has only a modest effect on LDL and more effective agents are available for lowering the concentration of LDL, the drug is of limited utility for patients with either familial hypercholesterolemia or polygenic hypercholesterolemia.
In a ... trial of primary prevention involving asymptomatic men with hypercholesterolemia, clofibrate lowered the plasma cholesterol concentration by only 6 to 11%. This very modest effect in unselected patients can be contrasted with that seen in patients with familial type-III hyperlipoproteinemia, in whom concentrations of cholesterol and triglycerides were lowered by approximately 50% and by as much as 80%, respectively. In such patients, administration of clofibrate results in the mobilization of deposits of cholesterol in tissues, accompanied by regression and disappearance of xanthomas. Clofibrate has no effect on hyperchylomicronemia, nor does it affect concentrations of HDL. Thus, clofibrate appears to have specific efficacy only in patients with familial type-III hyperlipoproteinemia.
The clinical evidence for the efficacy of clofibrate in preventing deaths from coronary artery disease is not encouraging. A number of clinical trials have been completed, and none has shown a clear-cut beneficial effect. A double blind study ... compared clofibrate with placebo in 10,000 men in the upper third of the distribution of plasma cholesterol concentrations. Patients treated with clofibrate had a decrease in nonfatal myocardial infarctions. ... Clofibrate treated patients had a higher noncardiac mortality rate than did control subjects, owing mainly to an increased incidence of malignant neoplasms and complications of cholecystectomy.
For more Therapeutic Uses (Complete) data for CLOFIBRATE (9 total), please visit the HSDB record page.

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Drug Warnings
Impotence observed after clofibrate treatment was the fourth most frequently occurring side effect of more than 30 side effects recorded ... . Although the exact mechanism is not known ...
Response to clofibrate is variable, and serum cholesterol and triglyceride concn should be determined prior to and regularly during (eg, every 3-6 mo) clofibrate therapy. If possible, the LDL and HDL fractions should also be determined and the LDL fraction rechecked during the first few months of clofibrate therapy ...
Liver function tests and complete blood cell counts should be performed periodically during clofibrate therapy ... some clinicians recommend serial determinations of plasma CK (CPK) concn during treatment with clofibrate ...
...THE DRUG IS OF LIMITED UTILITY FOR PATIENTS WITH TYPE-II HYPERLIPOPROTEINEMIA. FURTHERMORE, SINCE CLOFIBRATE MAY INCREASE THE CONCN OF LOW DENSITY LIPOPROTEIN IN SOME PATIENTS WITH ELEVATIONS OF VERY LOW DENSITY LIPOPROTEIN /VLDL/, THE EFFECTS OF THE DRUG SHOULD BE MONITORED BY SEQUENTIAL MEASUREMENT OF PLASMA LIPOPROTEINS. A SHIFT FROM AN EXCESS OF VLDL TO ONE OF LDL /LOW DENSITY LIPOPROTEIN/ SUGGESTS THE NECESSITY TO DISCONTINUE THE DRUG.
For more Drug Warnings (Complete) data for CLOFIBRATE (10 total), please visit the HSDB record page.

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Pharmacodynamics
Clofibrate is an antilipidemic agent similar to gemfibrozil. It acts to lower elevated serum lipids by reducing the very low-density lipoprotein fraction (S_f 20-400) rich in triglycerides. Serum cholesterol may be decreased, particularly in those patients whose cholesterol elevation is due to the presence of IDL as a result of Type III hyperlipoproteinemia. Several investigators have observed in their studies that clofibrate may produce a decrease in cholesterol linoleate but an increase in palmitoleate and oleate, the latter being considered atherogenic in experimental animals. The significance of this finding is unknown at this time. Reduction of triglycerides in some patients treated with clofibrate or certain of its chemically and clinically similar analogs may be associated with an increase in LDL cholesterol. Increase in LDL cholesterol has been observed in patients whose cholesterol is initially normal. Animal studies suggest that clofibrate interrupts cholesterol biosynthesis prior to mevalonate formation.

C12H15CLO3

242.7

242.07

C, 59.39; H, 6.23; Cl, 14.61; O, 19.78

637-07-0

Clofibrate;637-07-0

2796

Colorless to light yellow liquid

1.1±0.1 g/cm3

274.8±0.0 °C at 760 mmHg

118-119
< 25 °C

115.1±19.9 °C

0.0±0.5 mmHg at 25°C

1.505

3.32

0

3

5

16

232

0

ClC1C([H])=C([H])C(=C([H])C=1[H])OC(C(=O)OC([H])([H])C([H])([H])[H])(C([H])([H])[H])C([H])([H])[H]

KNHUKKLJHYUCFP-UHFFFAOYSA-N

InChI=1S/C12H15ClO3/c1-4-15-11(14)12(2,3)16-10-7-5-9(13)6-8-10/h5-8H,4H2,1-3H3

ethyl 2-(4-chlorophenoxy)-2-methylpropanoate

Clofibrate; Clofibrato; Ethyl clofibrate; Clofibratum; Atromid-S

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

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

DMSO: ~7 mg/mL (~28.8 mM)
Ethanol: ~5 mg/mL (~20.6 mM)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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