Comparative study on pharmacokinetics of Cephradine in diabetic and normal rats

Objective To study effects of diabetes mellitus(DM)on pharmacokinetics of cephradine(CED)by comparing the difference in pharmacokinetic behaviours of CED between diabetic and normal rats.Methods DM was induced in male rats by a single iv injection of alloxan 60 mg·kg-1;rats whose blood glucose was over 16 mmol·L-1 were taken as DM group.The rats were divided into DM group and normal control(CTL)group,which were subdivided into low dose(90 mg·kg-1)and high dose(180 mg·kg-1)subgroups.CED was administered by iv or po routes.Blood samples collected at different time post dosing were analyzed by RP-HPLC to yield CED plasma concentration time course.Chromatographic separation was achieved on a Kromasil C18 column(250×4.6 mm ID,5 μm);mobile phase,consisting of 0.025 mol·L-1 KH2PO4-MeOH-CH3CN(87;6∶7 v/v),was delivered at 1.0 mL·min-1;UV detector was set at 261 nm.The peak area ratio of CED to cephalexin(CEX)as internal standard vs concentraion of CED was used to construct calibration curve.50 μL aliquots of TCA-deproteined plasma samples were injected into chromatograph.Results The methodology validation including specificity,precision,accuracy,recovery,limit of quantitation,linearity,stability,etc.,showed that the HPLC assay developed by us completely met requirements of pharmacokinetic study Both DM and CTL groups showed the two-compartment model for iv dosing and extravascular one-compartment model for po dosing as well as first-order kinetics.However,in iv experiment,DM group,when compared with CTL group,presented a significantly shortened t1/2β and MRT as well as increased CL,reflected by t1/2 β 84-91 vs 116-120 min,MRT 61-70 vs 103-119 min;CL 23-25 vs 18-19 mL·min-1·kg-1(P<0.05);in po experiment,a markedly shorter t1/2 K and tmax as well as greater CL and Cmax in DM group than in CTL group were found;meanwhile,DM rats suffered from remarkably increased kidney weight(KW)and KW/BW ratio relative to CTL rats.Conclusions DM pathological status can speed up elimination of CED from body of rats;the compensatory hypertrophy and thereby hyperfunction of kidneys in early-stage diabetics may explain in part at least this accelerated elimanation.

Clinical Pharmacokinetic and Bioequivalence Studies of Two Brands of Cephradine in Healthy Korean Using HPLC Method

The goal of our research was to compare the pharmacokinetics and evaluate the bioequivalence of two brands of cephradine 500 mg capsules in 24 normal Korean volunteers. The plasma samples were acquired at 13 time points for 8 h after administration. The concentrations of cephradine in human plasma were measured by a high-performance liquid chromatography (HPLC). Isocratic mobile phase which consisted of acetonitrile, methanol, and 20 mM potassium phosphate (15/5/80, v/v/v, pH 3.48) was used to separate the analytical column cosmosil cholester (250 × 4.6 mm, 3 μm). Analytes were detected in ultraviolet (260 nm). The novel analytical method was described as simple sample preparation, a short retention time (less than 6 min) and making it suitable for use in clinical trials. Pharmacokinetic parameters, such as AUC0-t (20.54 vs 18.42 μg·h/mL), AUC0-infinity (21.22 vs 19.14 μg·h/mL), Cmax (12.69 vs 12.81 μg/mL), Tmax (1.22 vs 0.92 h), half-life (1.02 vs 1.13 h), extrapolation (3.22% vs 3.75%), and Ke (0.73 vs 0.69 h–1) were determined for the reference and test drugs in plasma. Pharmacokinetic parameters with a 90% confidence interval were 87% - 95% for AUC0-t and 91% - 115% for Cmax. They were satisfied within the bioequivalence range 80% - 125% of the KFDA guidelines. Therefore, our HPLC method was well applied in a bioequivalence and pharmacokinetic study of two formulations in normal subjects.

Investigation of the pharmacokinetics and determination of certain cephalosporins in rabbit plasma by a kinetic spectrophotometric method with the aid of chemometrics

This paper describes a kinetic spectrophotometric method for simultaneous determination of three cephalosporin antibiotics,cephradine,cefaclor and cefixime,with the aid of chemometrics. The method relies on their oxidation with KMnO4 to produce green manganate with different kinetic rates in alkaline medium. The proposed method was successfully applied to a pharmacokinetic study of three cephalosporin antibiotics in rabbit plasma via intravenous injections. The results indicated that the amount of cephradine,cefaclor and cefixime were reduced rapidly in rabbit blood,showing clear dose-dependency and the half-life of cefixime (160 min) was longer than those of cephradine (60 min) and cefaclor (60 min).