FENOFIBRATE- fenofibrate capsule
Glenmark Pharmaceuticals Inc., USA
Fenofibrate, USP (micronized), is a lipid regulating agent available as capsules for oral administration. Each capsule contains 67 mg, 134 mg or 200 mg of micronized fenofibrate, USP. The chemical name for fenofibrate, USP is Isopropyl 2-[p -(p -chlorobenzoyl)phenoxy]-2-methylpropanoate with the following structural formula:
The molecular formula is C20 H21 Cl O4 and the molecular weight is 360.83 g/mol. Fenofibrate, USP is practically insoluble in water, very soluble in methylene chloride and slightly soluble in alcohol. The melting point is 79°C to 82°C. Fenofibrate, USP is a white or almost white, crystalline powder which is stable under ordinary conditions.
Each 67 mg fenofibrate capsule, USP (micronized) contains the following inactive ingredients: black iron oxide, colloidal silicon dioxide, crospovidone, D&C Red #28, FD&C Blue #1, FD&C Red #40, gelatin, lactose monohydrate, magnesium stearate, potassium hydroxide, povidone, pregelatinized starch, shellac, sodium lauryl sulfate, talc and titanium dioxide.
Each 134 mg fenofibrate capsule, USP (micronized) contains the following inactive ingredients: black iron oxide, colloidal silicon dioxide, crospovidone, D&C Red #28, FD&C Blue #1, gelatin, lactose monohydrate, magnesium stearate, potassium hydroxide, povidone, pregelatinized starch, shellac, sodium lauryl sulfate, talc and titanium dioxide.
Each 200 mg fenofibrate capsule, USP (micronized) contains the following inactive ingredients: black iron oxide, colloidal silicon dioxide, crospovidone, D&C Red #28, FD&C Red #40, gelatin, iron oxide yellow, lactose monohydrate, magnesium stearate, potassium hydroxide, povidone, pregelatinized starch, shellac, sodium lauryl sulfate, talc and titanium dioxide.
FDA approved dissolution test specifications differ from USP.
A variety of clinical studies have demonstrated that elevated levels of total cholesterol (total-C), low density lipoprotein cholesterol (LDL-C), and apolipoprotein B (apo B), an LDL membrane complex, are associated with human atherosclerosis. Similarly, decreased levels of high density lipoprotein cholesterol (HDL-C) and its transport complex, apolipoprotein A (apo AI and apo AII) are associated with the development of atherosclerosis. Epidemiologic investigations have established that cardiovascular morbidity and mortality vary directly with the level of total-C, LDL-C, and triglycerides, and inversely with the level of HDL-C. The independent effect of raising HDL-C or lowering triglycerides (TG) on the risk of cardiovascular morbidity and mortality has not been determined.
Fenofibric acid, the active metabolite of fenofibrate, produces reductions in total cholesterol, LDL cholesterol, apolipoprotein B, total triglycerides and triglyceride rich lipoprotein (VLDL) in treated patients. In addition, treatment with fenofibrate results in increases in high density lipoprotein (HDL) and apoproteins apo AI and apo AII.
The effects of fenofibric acid seen in clinical practice have been explained in vivo in transgenic mice and in vitro in human hepatocyte cultures by the activation of peroxisome proliferator activated receptor α (PPARα). Through this mechanism, fenofibrate increases lipolysis and elimination of triglyceride-rich particles from plasma by activating lipoprotein lipase and reducing production of apoprotein C-III (an inhibitor of lipoprotein lipase activity). The resulting fall in triglycerides produces an alteration in the size and composition of LDL from small, dense particles (which are thought to be atherogenic due to their susceptibility to oxidation), to large buoyant particles. These larger particles have a greater affinity for cholesterol receptors and are catabolized rapidly. Activation of PPARα also induces an increase in the synthesis of apoproteins A-I, A-II and HDL-cholesterol.
Fenofibrate also reduces serum uric acid levels in hyperuricemic and normal individuals by increasing the urinary excretion of uric acid.
Clinical experience has been obtained with two different formulations of fenofibrate: a “micronized” and “non-micronized” formulation, which have been demonstrated to be bioequivalent. Comparisons of blood levels following oral administration of both formulations in healthy volunteers demonstrate that a single capsule containing 67 mg of the “micronized” formulation is bioequivalent to 100 mg of the “non-micronized” formulation. Three capsules containing 67 mg fenofibrate are bioequivalent to a single 200 mg fenofibrate capsule.
The absolute bioavailability of fenofibrate cannot be determined as the compound is virtually insoluble in aqueous media suitable for injection. However, fenofibrate is well absorbed from the gastrointestinal tract. Following oral administration in healthy volunteers, approximately 60% of a single dose of radiolabelled fenofibrate appeared in urine, primarily as fenofibric acid and its glucuronate conjugate, and 25% was excreted in the feces. Peak plasma levels of fenofibric acid occur within 6 to 8 hours after administration.
The absorption of fenofibrate is increased when administered with food. With micronized fenofibrate, the absorption is increased by approximately 35% under fed as compared to fasting conditions.
In healthy volunteers, steady-state plasma levels of fenofibric acid were shown to be achieved within 5 days of dosing with single oral doses equivalent to 67 mg fenofibrate and did not demonstrate accumulation across time following multiple dose administration. Serum protein binding was approximately 99% in normal and hyperlipidemic subjects.
Following oral administration, fenofibrate is rapidly hydrolyzed by esterases to the active metabolite, fenofibric acid; no unchanged fenofibrate is detected in plasma.
Fenofibric acid is primarily conjugated with glucuronic acid and then excreted in urine. A small amount of fenofibric acid is reduced at the carbonyl moiety to a benzhydrol metabolite which is, in turn, conjugated with glucuronic acid and excreted in urine.
In vivo metabolism data indicate that neither fenofibrate nor fenofibric acid undergo oxidative metabolism (e.g., cytochrome P450) to a significant extent.
After absorption, fenofibrate is mainly excreted in the urine in the form of metabolites, primarily fenofibric acid and fenofibric acid glucuronide. After administration of radiolabelled fenofibrate, approximately 60% of the dose appeared in the urine and 25% was excreted in the feces.
Fenofibric acid is eliminated with a half-life of 20 hours, allowing once daily administration in a clinical setting.
In elderly volunteers 77 to 87 years of age, the oral clearance of fenofibric acid following a single oral dose of fenofibrate was 1.2 L/h, which compares to 1.1 L/h in young adults. This indicates that a similar dosage regimen can be used in the elderly, without increasing accumulation of the drug or metabolites.
Fenofibrate has not been investigated in adequate and well-controlled trials in pediatric patients.
No pharmacokinetic difference between males and females has been observed for fenofibrate.
The influence of race on the pharmacokinetics of fenofibrate has not been studied, however fenofibrate is not metabolized by enzymes known for exhibiting inter-ethnic variability. Therefore, inter-ethnic pharmacokinetic differences are very unlikely.
The pharmacokinetics of fenofibric acid was examined in patients with mild, moderate and severe renal impairment. Patients with severe renal impairment (creatinine clearance [CrCl] ≤ 30 mL/min) showed 2.7-fold increase in exposure for fenofibric acid and increased accumulation of fenofibric acid during chronic dosing compared to that of healthy subjects. Patients with mild to moderate renal impairment (CrCl 30 to 80 mL/min) had similar exposure but an increase in the half-life for fenofibric acid compared to that of healthy subjects. Based on these findings, the use of fenofibrate should be avoided in patients who have severe renal impairment and dose reduction is required in patients having mild to moderate renal impairment.
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