Widecillin Mechanism of Action

Pharmacology: Widecillin is a new derivative of 6-aminopenicillanic acid. It is a bactericidal antibiotic which is effective against the same range of organisms as ampicillin and has a similar mode of action.
Microbiology: Antibacterial Activity: Widecillin shows antibacterial activity against gram-positive and gram-negative bacteria. The MICs of Widecillin against the major infectious microorganisms are shown in Table 1.


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Pharmacokinetics: Widecillin is well absorbed from the gastrointestinal tract and is absorbed more rapidly and completely than ampicillin independently of the presence of food in the alimentary canal. The concentration of Widecillin in the blood is twice higher than the same dose of ampicillin.
Absorption and Excretion: In normal adults, preprandial oral administration of 125 or 250 mg (potency) of Widecillin produces a mean peak blood concentration of 2.6 or 5.3 mcg/mL, respectively after 2 hrs. This decreases gradually thereafter and is 0.15 or 0.3 mcg/mL after 6 hrs.
The urinary-recovery rate within 6 hrs after administration is 54% or 60.2%, respectively. In normal adults, postprandial oral administration of 500 mg (potency) of amoxicillin produces a mean peak blood concentration of 7.4 mcg/mL after 3 hrs. This level is the same as the 7.6 mcg/mL attained following preprandial dosing.
Tissue Concentration: Oral administration of 100 mg (potency) amoxicillin to rats produces the following tissue concentrations after 1 hr: 64.2 mcg/g in the kidney, 62.6 mcg/g in the liver, 15.9 mcg/mL in the blood, 10.7 mcg/g in SC soft tissue, 8.1 mcg/g in the lung and 7 mcg/g in the spleen.
Toxicology: LD₅₀ (mg/kg): See Table 2.


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