Multicompartment pharmacokinetics of netilmicin

Area of Science:

• Pharmacology
• Clinical Pharmacy
• Drug Metabolism

Background:

• Netilmicin (NM) is an aminoglycoside antibiotic.
• Understanding the pharmacokinetic profile of NM is essential for optimizing therapeutic efficacy and minimizing toxicity.

Purpose of the Study:

• To characterize the pharmacokinetics of a single dose of netilmicin in healthy volunteers.
• To determine the elimination half-lives, volume of distribution, and clearance of NM.
• To assess the implications of NM's pharmacokinetic profile on repetitive dosing and potential tissue accumulation.

Main Methods:

• A single oral dose of netilmicin was administered to 6 healthy volunteers.
• Serum and urine concentrations of NM were measured over 24 and 72 hours, respectively.
• Pharmacokinetic parameters were calculated using a three-compartment open model and a modified radioenzymatic assay.

Main Results:

• Netilmicin demonstrated biphasic elimination with terminal half-lives of 1.99 h (t 1/2 beta) and 36.89 h (t 1/2 gamma).
• The volume of distribution at steady-state (Vdss) was 0.68 L/kg, significantly larger than previously reported.
• Plasma clearance was 91 mL/min, and renal clearance was 67 mL/min, with urinary excretion observed up to 72 hours.

Conclusions:

• The prolonged terminal elimination phase of netilmicin necessitates consideration in repetitive dosing regimens to avoid underestimation of drug levels.
• Accumulation of netilmicin in renal and other tissues is likely during prolonged treatment, similar to other aminoglycosides.
• The pharmacokinetic data suggest potential clinical implications for dosing strategies and monitoring to mitigate toxicity risks.