Quantitative Monitoring of Cefradine in Human Urine Using a Luminol/Sulfobutylether–β-Cyclodextrin Chemiluminescence System

Abstract

In this paper, a sensitive, rapid, and simple flow-injection chemiluminescence (FI-CL) technique is described for determining cefradine in human urine and capsule samples at the picogram level. The results show that cefradine within 0.1–100.0 nmol/L quantitatively quenches the CL intensity of the luminol/sulfo butylether–β-cyclodextrin (SBE–β-CD) system, with a relative correlation coefficient r of 0.9931. Subsequently, the possible mechanism for the quenching phenomenon is discussed in detail using the FI-CL and molecular docking methods. The proposed CL method, with a detection limit of 0.03 nmol/L (3σ) and relative standard deviations <3.0% (N = 7), is then implemented to monitor the excretion of cefradine in human urine. After orally administration, the cefradine reaches a maximum value of 1.37 ± 0.02 mg/mL at 2.0 h in urine, and the total excretion is 4.41 ± 0.03 mg/mL within 8.0 h. The absorption rate constant ka, the elimination rate constant ke, and the half-life t1/2 are 0.670 ± 0.008 h−1, 0.744 ± 0.005 h−1, and 0.93 ± 0.05 h, respectively.