Pharmacokinetics of pazufloxacin mesilate in elderly subjects

• Published in: Japanese Journal of Chemotherapy Vol. 48; no. 8; pp. 633 - 644
• Main Authors: Yajima, Youichi, Yoshizawa, Hisao, Takagi, Kenzo
• Format: Journal Article
• Language: Japanese
• Published: Japanese Society of Chemotherapy 2000; 公益社団法人 日本化学療法学会
• Subjects: pazufloxacin注射薬; pharmacokinetics; PZFX; ニューキノロン; 高齢者
• ISSN: 1340-7007; 1884-5886
• DOI: 10.11250/chemotherapy1995.48.633

The pharmacokinetics of a new quinolone, pazufloxacin (PZFX) mesilate, were evaluated in 10 elderly volunteers. Five hundred milligrams of PZFX mesilate were administered by intravenous drip infusion over a period of 30 minutes. The concentrations of PZFX in the serum and urine were then determined using high-performance liquid chromatography. The pharmacokinetic parameters were calculated for groups of elderly subjects aged 65-74 years, ≥75 years and≥65 years using a two-compartment model, Higher peak concentration (Cmax) and area under the curve (AUC) levels, lower systemic and renal clearance values, and a lower steady state of distribution volume were observed in the≥75 group. However, a longer elimination half-lives (T1/2β) value was not observed. The average urinary excretion rate of PZFX after 24 hours was 83.5%. Renal clearance accounted for the major form of PZFX elimination, confirming that PZFX is primarily excreted in the urine in the elderly. No significant correlation was observed between the systemic clearance and creatinine clearance (CLCR). The effects of repeated administrations of PZFX mesilate (500 mg× 2-3 times per day for 7 days) were simulated using the observed parameters. Based on these calculations, the accumulation of PZFX seems unlikely. None of the elderly subjects experienced any adverse effects or produced any abnormal laboratory data. PZFX mesilate tolerance was good for a Cmax of up to 23 μg/mL. However, we recommend that the administration of PZFX mesilate in elderly subjects be carefully monitored to prevent a significant decrease in renal function.