Abstract: Aim & Methods To study the effect of cephradine on pharmacokinetic action of netilmicin sulfate, the concentrations of netilmicin sulfate in serum and urine were determined by a high performance liquid chromatography-indirect photometric determination (HPLC-IPD) method at the wavelength of 262nm after intravenous drip of 5mg/kg of netilmicin sulfate in 14 patients who had been divided into two groups, with the patients in one group simultaneously taking orally cephradine. The data obtained were fitted with a PKBP-N1 program on computer. Results The disposition was conformed to a two-compartment model with T_1/2β = 2. 40±1. 01h and 4. 33±1. 43h(P<0. 01), and AUC_0~24h= 63. 42±30. 00mg/h·L and 78. 54±32. 88 mg/h · L(P<0. 01) in two groups. There was a remarkable discrepancy for the recla-mation of netilmicin in urine between two groups. Conclusion The bioavailability of netilmicin was raised and reclamation in urine descended with cephradine.

Key words: netilmicin sulfate, cephradine, pharmacokinetics, HPLC-IDP