Chemical Properties
Crystalline Solid
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.
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-).
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.
Pharmacokinetics
Oral absorption: 40–70%
Cmax 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
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.
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.
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.
