Glibenclamide

Absorption

Elderly patients taking glyburide reached a Cmax of 211-315ng/mL with a Tmax of 0.9-1.0h, while younger patients reached a Cmax of 144-302ng/mL with a Tmax of 1.3-3.0h. Patients taking glyburide have and AUC of 348ng*h/mL.

Toxicity

The oral LD50 in rats is >3200mg/kg, in mice is >1500mg/kg, in rabbits is >10,000mg/kg, and in guinea pigs is >1500mg/kg.
Patients experiencing an overdose may present with hypoglycemia. Mild hypoglycemia should be treated with oral glucose and adjustments to drug doses or meal schedules. Severe hypoglycemia may present with coma, seizure, and neurological impairment. This should be treated immediately in hospital with intravenous glucose and monitoring for 24-48 hours.

Description

Glyburide (10238-21-8) is a second generation oral hypoglycemic agent. Acts via ATP-dependent K+ channel (Kir6, KATP) block.1?Inhibits Kir6 currents in the pancreas, causing an increase in intracellular Ca2+ and insulin secretion. Glyburide also inhibits recombinant CFTR Cl- channels with an IC50 of 20 μM.2?Cell permeable.

Chemical properties

White or almost white, crystalline powder

Originator

Daonil,Hoechst,Germany

The Uses of Glibenclamide

antihyperglycemic

The Uses of Glibenclamide

Glyburide is a second generation sulfonylurea with hypoglycemic activity. Glyburide is an antidiabetic.

The Uses of Glibenclamide

An ATP-dependent KIR6 and CFTR Cl- channel blocker

The Uses of Glibenclamide

Glyburide (Glibenclamide) is a sulfonylurea compound that modulates insulin production. Sulfonylureas bind to ATP-dependent K+ channels in beta cells of the pancreas, depolarizing them and stimulating the release of Ca2+, which in turn stimulates insulin production. Glyburide (Glibenclamide) is an ATP-dependent K+ channel (KIR6, KATP) and CFTR Cl- channel blocker. This compound inhibits recombinant CFTR Cl- channels (IC50 = 20 ?M).

What are the applications of Application

Glyburide (Glibenclamide) is an ATP-dependent KIR6 and CFTR Cl- channel blocker

Background

Glyburide is a second generation sulfonylurea used to treat patients with diabetes mellitus type II. It is typically given to patients who cannot be managed with the standard first line therapy, metformin. Glyburide stimulates insulin secretion through the closure of ATP-sensitive potassium channels on beta cells, raising intracellular potassium and calcium ion concentrations.
Glyburide was granted FDA approval on 1 May 1984. A formulation with metformin was granted FDA approval on on 31 July 2000.

Indications

Glyburide is indicated alone or as part of combination product with metformin, as an adjunct to diet and exercise, to improve glycemic control in adults with type 2 diabetes mellitus.

Definition

ChEBI: An N-sulfonylurea that is acetohexamide in which the acetyl group is replaced by a 2-(5-chloro-2-methoxybenzamido)ethyl group.

Manufacturing Process

To a solution of 10.2 g of 4-(β-(2-ethoxy-5-chlorobenzamido)ethyl)- benzenesulfonamide in 12.5 ml of 2 N sodium hydroxide solution and 30 ml acetone are added dropwise, at 0-5°C, 3.3 g of cyclohexyl isocyanate. The whole is stirred for 3 hours, diluted with water and methanol, undissolved matter is separeted by filtration. The filtrate is acidified with dilute hydrochloric acid. The 4-(β-(2-ethoxy-5-chlorobenzamido)ethyl)- benzenesulfonyl)-N'-cyclohexylurea which precipitates in the form of crystals melts after recrystallization from methanol at 168-170°C.

brand name

Micronase (Pharmacia & Upjohn).

Therapeutic Function

Oral hypoglycemic

General Description

Glyburide (glibenclamide) is 5-chloro-N-[2-[4-[[[(cyclohexylamino)carbonyl]amino]sulfonyl]phenyl]ethyl]-2-methoxybenzamide; this compound can also be named asthe urea—see preceding discussion (Diabeta, Glynase,generic). Some tablet formulations contain micronized drug(formerly Micronase, now only generic). Combinations areavailable with metformin in the United States (Glucovance,generic; tablets, mg glipizide/mg metformin as hydrochloride:1.25/250, 2.5/500, 5/500).

General Description

Similar to glipizide, glyburide, 1-[[p-[2-(5-chloro-o-anisamido)ethyl]-phenyl]sulfonyl]-3-cyclohexylurea(DiaBeta, Micronase, Glynase), is a second-generationoral hypoglycemic agent. The drug has a half-life eliminationof 10 hours, but its hypoglycemic effect remains for upto 24 hours.

Biological Activity

ATP-dependent K + channel (K ATP ) and CFTR Cl - channel blocker. Inhibits K ATP currents in the pancreas, causing an increase in intracellular Ca 2+ and insulin secretion. Inhibits recombinant CFTR Cl- channels with an IC 50 of 20 μ M.

Biochem/physiol Actions

Selectively blocks ATP-sensitive K+ channels; high affinity binding sites found in brain, pancreatic β cells, and cardiovascular system.

Mechanism of action

This drug belongs to the second-generation sulfonylurea derivatives. Like all of the other oral hypoglycemic drugs examined, it is a β-cell stimulant in pancreas; but on the other hand, it increases the sensitivity to insulin, the degree to which it binds with target cells. At the same time, it differs in that it is easier to tolerate. The hypoglycemic effect sets in at significantly lower doses than with first-generation drugs.

Pharmacokinetics

Glyburide is a second generation sulfonylurea that stimulates insulin secretion through the closure of ATP-sensitive potassium channels on beta cells, raising intracellular potassium and calcium ion concentrations. Glibenclamide has a long duration of action as it is given once daily, and a wide therapeutic index as patients are started at doses as low as 0.75mg but that can increase as high as 10mg or more. Patients taking glyburide should be cautioned regarding an increased risk of cardiovascular mortality as seen with tolbutamide, another sulfonylurea.

Clinical Use

Non-insulin dependent diabetes mellitus

Synthesis

Glyburide, 1-[4-[2-(5-chloro-2-methoxybenzamido)ethyl]-phenylsulfonyl]-3- cyclohexylurea (26.2.11), is a second-generation drug that differs from those described above in that it has a more complex structure in the sulfonylamide region of the molecule into which an additional pharmacophore group is added. It is synthesized from 2-methoxy-5-chlorobenzoic acid chloride, which is transformed into an amide 26.2.9 by reacting it with 2-phenylethylamine. This undergoes subsequent sulfonylchlorination by chlorosulfonic acid, and then amination by ammonia, which gives sulfonamide 26.2.10. The resulting sulfonamide is reacted with cylclohexylisocyanate to give the desired glyburide (26.2.11).

Drug interactions

Potentially hazardous interactions with other drugs
Analgesics: effects enhanced by NSAIDs.
Antibacterials: effects enhanced by chloramphenicol, sulphonamides, tetracyclines and trimethoprim; effects possibly enhanced by ciprofloxacin and norfloxacin; effect reduced by rifamycins.
Anticoagulants: effect possibly enhanced by coumarins; also possibly changes to INR.
Antifungals: concentration increased by fluconazole and miconazole and possibly voriconazole.
Bosentan: increased risk of hepatoxicity - avoid.
Ciclosporin: may increase ciclosporin levels.
Lipid-regulating drugs: absorption reduced by colesevelam; concentration possibly increased by fluvastatin; possibly additive hypoglycaemic effect with fibrates.
Sulfinpyrazone: enhanced effect of sulphonylureas.

Metabolism

Glibenclamide is metabolised, almost completely, in the liver, the principal metabolite being only very weakly active.
About 50% of a dose is excreted in the urine and 50% via the bile into the faeces.

Metabolism

Glyburide is metabolized mainly by CYP3A4, followed by CYP2C9, CYP2C19, CYP3A7, and CYP3A5. These enzymes metabolize glyburide to 4-trans-hydroxycyclohexyl glyburide (M1), 4-cis-hydroxycyclohexyl glyburide (M2a), 3-cis-hydroxycyclohexyl glyburide (M2b), 3-trans-hydroxycyclohexyl glyburide (M3), 2-trans-hydroxycyclohexyl glyburide (M4), and ethylhydroxycyclohexyl glyburide (M5). The M1 and M2b metabolites are considered active, along with the parent molecule.

storage

Store at RT

References

1) Brogden et al. (1979), Glipizide: a review of its pharmacological properties and therapeutic use; Drugs, 18 329 2) Sheppard and Welsh (1992), Effect of ATP-sensitive K+ channel regulators on cystic fibrosis transmembrane conductance regulator chloride currents; J. Gen. Physiol., 100 573