PENICILLIN V

Absorption

Upon oral administration, phenoxymethylpenicillin is rapidly but incompletely absorbed. The bioavailability of phenoxymethylpenicillin ranges from 25 to 60%. Compared to the free acid form of the drug, the calcium or potassium salts of phenoxymethylpenicillin displays better absorption profiles. It is reported that fasting state enhances the drug absorption. The peak plasma concentrations of 200 to 700 ng/mL are achieved in 2 hours following an oral dose of 125 mg. Following an oral dose of 500 mg, the peak plasma concentrations of 3 to 5 μg/mL are reached in 30 to 60 minutes post-dose.

Toxicity

The oral LD50 is >1040 mg/kg in rats. Nausea, vomiting, black hairy tongue, and epigastric distress are common reactions to oral penicillins. In rare cases, neuromuscular sensitivity and seizures may be seen with antibiotics and supportive treatments are advised and further drug absorption should be limited through induced emesis or gastric lavage, followed by administration of activated charcoal. Severe hypersensitivity reactions, often leading to death, have been reported with penicillin therapies. Although phenoxymethylpenicillin was shown to be excreted in human breast milk, the use of this drug in pregnant or nursing women is regarded generally safe.

Chemical properties

Crystalline Solid

The Uses of PENICILLIN V

Phenoxymethylpenicillin or penicillin V is acid-resistant and used instead of penicillin G for oral use. It is active with respect to Gram-positive (staphylococcus, streptococcus, pneumococcus), and Gram-negative (meningococcus, gonococcus) cocci, spirochaeta, clostridia, and corynebacteria.
Phenoxymethylpenicillin is used for bronchitis, pneumonia, angina, scarlet fever, gonorrhea, syphilis, purulent skin and soft-tissue wounds, and other infectious diseases. Synonyms of this drug are bermycin, isocillin, cristapen, fenospen, uticillin, and others.

The Uses of PENICILLIN V

Penicillin antibacterial.

The Uses of PENICILLIN V

Penicillin V is an antibacterial agent. This compound is a contaminant of emerging concern (CECs).

Indications

Indicated for the treatment of mild to moderately severe infections due to penicillin G--sensitive microorganisms, with the use of bacteriological studies (including sensitivity tests) and clinical response.
Phenoxymethylpenicillin may be used for the treatment of:
Off-label
Indicated for use as prophylaxis against bacterial endocarditis in patients with congenital heart disease or rheumatic or other acquired valvular heart disease when they undergo dental procedures and surgical procedures of the upper respiratory tract.

Background

Phenoxymethylpenicillin is a narrow spectrum antibiotic also commonly referred to as Penicillin V or Penicillin VK. It is a phenoxymethyl analog of Penicillin G, or benzylpenicillin. An orally active naturally penicillin, phenoxymethylpenicillin is used to treat mild to moderate infections in the respiratory tract, skin, and soft tissues caused by penicillin G--sensitive microorganisms. Phenoxymethylpenicillin has also be used in some cases as prophylaxis against susceptible organisms. While there have been no controlled clinical efficacy studies that were conducted, phenoxymethylpenicillin has been suggested by the American Heart Association and the American Dental Association for use as an oral regimen for prophylaxis against bacterial endocarditis in patients with congenital heart disease or rheumatic or other acquired valvular heart disease when they undergo dental procedures and surgical procedures of the upper respiratory tract, except for those who are at an elevated risk for endocarditis.

Definition

ChEBI: Phenoxymethylpenicillin is a penicillin compound having a 6beta-(phenoxyacetyl)amino side-chain. It is a penicillin allergen and a penicillin. It is a conjugate acid of a phenoxymethylpenicillin(1-).

What are the applications of Application

Phenoxymethylpenicillin was produced in the culture broth of Penicillium chrysogenum when phenoxyacetic acid was added to the medium at Biochemie in 1953. It is more stable against acid than benzylpenicillin and is used as an orally active penicillin. Its therapeutic applications are the same as those of benzylpenicillin.

brand name

V-Cillin(Lilly).

Antimicrobial activity

The antibacterial spectrum and level of activity are similar to that of benzylpenicillin. Enteric Gram-negative bacilli are highly resistant.

General Description

White crystalline powder.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

Stable in air up to 37%; relatively stable to acid. PENICILLIN V is incompatible with acids, oxidizing agents (especially in the presence of trace metals), heavy metal ions such as copper, lead, zinc and mercury; glycerol, sympathomimetic amines, thiomersal, wood alcohols, cetostearyl alcohol, hard paraffins, macrogols, cocoa butter and many ionic an nonionic surface-active agents. PENICILLIN V is also incompatible with alkalis, compounds leached from vulcanized rubber, hydrochlorides of tetracyclines and organic peroxides. Other incompatibilities include reducing agents, alcohols, other hydroxy compounds, self-emulsifying stearyl alcohol, emulsifying wax, lanolin, crude cholinesterated bases, glycol, sugars, amines, aminacrine hydrochloride, ephedrine, procaine, rubber tubing, thiamine hydrochloride, zinc oxide, oxidized cellulose, iodine, iodides, thiols, chlorocresol and resorcinol. PENICILLIN V may also be incompatible with naphthalene oils and vitamin B.

Health Hazard

SYMPTOMS: Symptoms of exposure to PENICILLIN V include hypersensitization, skin rashes, contact dermatitis, oral lesions, fever, eosinophilia, interstitial nephritis, angioedema, serum sickness, anaphylaxis, "Arthus" phenomenon; irritation of the Gastrointestinal tract; phlebitis; bronchoconstriction with severe asthma, or abdominal pain, nausea, vomiting, extreme weakness and fall in blood pressure, diarrhea, and purpuric skin eruptions.

Fire Hazard

Flash point data for PENICILLIN V are not available; however PENICILLIN V is probably combustible.

Pharmacokinetics

Phenoxymethylpenicillin works against penicillin-sensitive microorganisms with bactericidal effects. It targets the bacteria during its active multiplication stage by interfering with bacterial cell wall peptidoglycan synthesis. In vitro, phenoxymethylpenicillin was shown to be active against staphylococci (except penicillinase-producing strains), streptococci (groups A, C, G, H, L and M), and pneumococci, as well as Corynebacterium diphtheriae, Bacillus anthracis, Clostridia, Actinomyces bovis, Streptobacillus moniliformis, Listeria monocytogenes, Leptospira, Neisseria gonorrhoeae, and Treponema pallidum.

Pharmacokinetics

Oral absorption: 40–70%
C_max 250 mg oral: 2 mg/L after 1 h
Plasma half-life: c. 0.5 h
Volume of distribution: 0.2 L/kg
Plasma protein binding: 80%
Absorption
Owing to acid stability, it is not destroyed in the stomach, but absorption is variable, about 30% remaining in the feces. Absorption is better after administration in the fasting state.
Metabolism and excretion
It is fairly extensively metabolized and degraded in the bowel. Some 60% of the dose is excreted in the urine, 25% in the unchanged form and the remainder as metabolites.

Clinical Use

It may be prescribed for many indications for which benzylpenicillin is suitable, including streptococcal pharyngitis and skin sepsis, but is not recommended for initial therapy of serious infections. It is useful for continuation therapy after initial control of the disease by parenteral benzylpenicillin when prolonged treatment is required. It has been used prophylactically in recurrent pneumococcal meningitis after head injury and in rheumatic fever. It is not appropriate for infections caused by H. influenzae or Gram-negative bacteria, and is not recommended for the treatment of gonorrhea, syphilis or leptospirosis.

Clinical Use

In 1948, Behrens et al. reported penicillin V, phenoxymethylpenicillin(Pen Vee, V-Cillin) as a biosyntheticproduct. It was not until 1953, however, that its clinicalvalue was recognized by some European scientists. Sincethen, it has enjoyed wide use because of its resistance tohydrolysis by gastric juice and its ability to produce uniformconcentrations in blood (when administered orally). Thefree acid requires about 1,200 mL of water to dissolve 1 g, and it has an activity of 1,695 units/mg. For parenteralsolutions, the potassium salt is usually used. This salt is verysoluble in water. Solutions of it are made from the dry saltat the time of administration. Oral dosage forms of thepotassium salt are also available, providing rapid, effectiveplasma concentrations of this penicillin. The salt of phenoxymethylpenicillinwith N,N'-bis(dehydroabietyl)ethylenediamine(hydrabamine, Compocillin-V) provides a verylong-acting form of this compound. Its high water insolubilitymakes it a desirable compound for aqueous suspensionsused as liquid oral dosage forms.

Side Effects

Those common to penicillins. As with all penicillins, patients with a history of hypersensitivity to penicillins should be treated cautiously, as serious anaphylactic responses may occur.

Safety Profile

Poison by intraperitoneal, subcutaneous, and intravenous routes. Human systemic effects by ingestion: impaired liver function, dermatitis, fever. Mutation data reported. When heated to decomposition it emits very toxic fumes of SOx and NOx.

Synthesis

Phenoxymethylpenicillin, [2S-(2α,5α,6β)]-3,3-dimethyl-7-oxo- 6-(phenoxyacetamido)-4-thia-1-azabicyclo[3.2.0]-heptan-2-carboxylic acid (32.1.1.2), is also obtained biotechnologically using the fungus P. chrysogenum as the producer and phenoxyacetic acid as the precursor. As with benzylpenicillin, there is a purely synthetic way of making phenoxymethylpenicillin.

Metabolism

About 35-70% of an oral dose is metabolized to penicilloic acid, an inactive metabolite. Small amounts of 6-aminopenicillanic acid have been recovered in the urine of patients on penicillin G. A small percentage of the drug appears to be hydroxylated into one or more active metabolites, which are also excreted via urine.