What does phenobarbital dissolve in?

What does phenobarbital dissolve in?

Phenobarbital has poor water solubility (1 mg/ml) but it is freely soluble in ethanol (100 mg/ml). Its solubility usually can be increased by addition of water–miscible solvents.

Is phenobarbital sodium water soluble?

Solubility: Soluble in water (1 g/ml) or ethanol (100 mg/ml). Disposal: Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. This product is controlled by the Drug Enforcement Administration.

Is phenobarbital an acid or base?

Phenobarbital is an unionized acid with a pKa of 7.4, and, therefore, the conjugate base is anionic. The patient’s urinary pH is 5.4.

Which indicator is used in assay of phenobarbital?

Phenobarbitone is assayed by non-aqueous titration.In this method,drug is dissolved in the pyridine and titrated with sodium hydroxide solution using thymolphthalein as an indicator.

How is phenobarbital absorbed?

Phenobarbital is absorbed in varying degrees following oral, rectal or parenteral administration. The salts are more rapidly absorbed than are the acids. The rate of absorption is increased if the sodium salt is ingested as a dilute solution or taken on an empty stomach.

Does phenobarbital come in a liquid?

Other strengths are still available, including the 16.2 mg, 32.4 mg, 64.8 mg, and 97.2 mg tablets. The phenobarbital oral liquid is also still available.

How is phenobarbital influenced by pH?

Because phenobarbital is a weak acid, this pH gradient favors movement of phenobarbital into the brain during status epilepticus. Motor paralysis prevented the development of systemic acidosis and the brain-blood partition of phenobarbital was similar to that of nonconvulsing controls.

Why is phenobarbital an acid?

Phenobarbital is a long-acting barbituric acid derivative with antipsychotic property. Phenobarbital binds to and activates the gamma-aminobutyric acid (GABA)-A receptor, thereby mimicking the inhibitory actions of GABA in the brain.

Which heterocyclic ring is present in phenobarbital?

Phenobarbital sodium is a barbiturate that is the sodium salt of phenobarbital (barbituric acid substituted at C-5 by ethyl and phenyl groups). It is an organic sodium salt and a member of barbiturates.

Where is phenobarbital absorbed?

In situ studies indicate that phenobarbital is primarily absorbed from the intestines. Thus, it is concluded that the presence of food decreased the pharmacological activity of phenobarbital by decreasing the rate of absorption and that this decreased absorption rate is due primarily to slowed gastric emptying.

Can phenobarbital be crushed?

To take tablets: To swallow the tablets, take whole with a glass of water. To crush tablets: – Crush and mix with a small amount of liquid or soft food.

What is liquid phenobarbital?

Phenobarbital is a substituted pyrimidine derivative in which the basic structure is barbituric acid, a substance that has no CNS activity. CNS activity is obtained by substituting alkyl, alkenyl, or aryl groups on the pyrimidine ring. Each 5 mL (teaspoon) contains 20 mg Phenobarbital and Alcohol 15%.

Is phenobarbital soluble in water?

Phenobarbital is a barbituric acid derivative and occurs as white, odorless, small crystals or crystalline powder that is very slightly soluble in water; soluble in alcohol, in ether, and in solutions of fixed alkali hydroxides and carbonates; sparingly soluble in chloroform.

What is the half-life of phenobarbital in adults?

The plasma half-life for phenobarbital in adults ranges between 53 and 118 hours with an mean of 79 hours.

Is P-hydroxyphenobarbital an inactive metabolite?

Phenobarbital is hydroxylated by the liver to form p-hydroxyphenobarbital, an inactive metabolite. Phenobarbital is a potent inducer of the enzymes involved in the metabolism of other drugs, but there is no conclusive evidence that phenobarbital accelerates its own metabolism.

What are the contraindications for phenobarbital?

Phenobarbital is contraindicated in patients who are hypersensitive to barbiturates, in patients with a history of manifest or latent porphyria, and in patients with marked impairment of liver function or respiratory disease in which dyspnea or obstruction is evident.