Disposition kinetics, renal clearance and urinary excretion of cefixime in adolescent Pakistani boys - DRUG ANALYSIS REPORT

OBJECTIVE

To investigate the role of environmental variation, genetic differences and age on disposition kinetics, renal clearance and urinary excretion of oral cefixime 400mg in healthy boys.

METHODS

The cross-sectional study was conducted at the University of Agriculture, Faisalabad, Pakistan, from August 2014 to July 2015, and comprised healthy boys aged 12-17 years after oral administration of cefixime capsule 400mg. Serum and urine samples were collected before and after drug administration and were stored at - 20oC until evaluation of cefixime concentration in each sample by high performance liquid chromatography. Drug concentration versus time data was used for pharmacokinetic calculations using one compartment model. Data obtained for urinary excretion and renal clearance of cefixime was analysed using regression-correlation analysis.

RESULTS

There were eight boys in the study. Mean values for elimination half-life, volume of distribution and total body clearance were 2.4}0.2 hours, 0.9}0.0L/kg and 0.3}0.0L/h/kg, respectively. The ratio of renal clearance of cefixime (0.7 ml/min/kg) to that of endogenous creatinine (0.8ml/min/kg) was 0.9. Cumulative mean percentage of cefixime excreted from young adolescent boys was 11.6 } 0.5%.

CONCLUSION

Other than filtration, back-diffusion was also involved in renal handling of cefixime. There was enough indication that major portion of cefixime was excreted from a young body through bile.

PEPT1- and OAT1/3-mediated drug-drug interactions between bestatin and cefixime in vivo and in vitro in rats, and in vitro in human

The purpose of the present study was to elucidate the transporter-mediated pharmacokinetics mechanism of drug-drug interactions (DDIs) between bestatin and cefixime. The plasma concentrations and bioavailabilities of bestatin and cefixime were decreased after oral co-administration in rats. The uptake in rat everted intestinal sacs of bestatin and cefixime were dramatically declined after co-administration of the two drugs. Bestatin and cefixime can mutually competitively inhibit the uptake by hPEPT1-HeLa cells. The plasma concentrations of bestatin and cefixime were increased; however, the cumulative biliary excretion had no significant change, and the cumulative urinary excretion and renal clearance of the two drugs in rats decreased after intravenous coadministration. Moreover, decreased uptake of the two drugs was observed in human kidney slices, rat kidney slices and hOAT1/hOAT3-transfected HEK293 cells when bestatin and cefixime were coadministered. The accumulation of bestatin and cefixime in kidney slices can be inhibited by p-aminohippurate, benzylpenicillin and probenecid, but not by tetraethyl ammonium. The results suggest that intestinal absorption and renal excretion of bestatin and cefixime can be inhibited when the two drugs were co-administered in rats. The pharmacokinetic mechanism indicates that the DDIs between bestatin and cefixime are mainly mediated by Pept1 and Oat1/3 in rats. PEPT1 and OAT1/3 are the target transporters of DDIs between bestatin and cefixime in human kidney slices and human transfected cells, proposing possible drug-drug interaction in humans.

Bioanalytical method development and validation for simultaneous estimation of cefixime and dicloxacillin by RP-HPLC in human plasma

An accurate, rapid and simple reversed-phase high performance liquid chromatography (RP-HPLC) bioanalytical method was developed and validated for simultaneous estimation of cefixime, dicloxacillin in human plasma using ezetimibe as an internal standard. The cefixime, dicloxacillin and internal standard were extracted by liquid-liquid extraction technique. Chromatographic separation is accomplished using CAPCELL PAK C18 (4.6 mm × 250 mm, 5 m) analytical column. The mobile phase consisted of phosphate buffer, acetonitrile and methanol in 42:55:03 proportions. Detection and quantification were performed by UV/Vis detection at 225 nm. The lower limit of quantification was 0.5 µg mL(-1) for both cefixime and dicloxacillin in human plasma. The calibration curves were linear over the concentration range 0.5 to 40 µg mL(-1) for both drugs in human plasma. The method was quantitatively evaluated in terms of linearity, precision, accuracy, recovery, selectivity, and stability. The method was found to be simple, convenient and suitable for the analysis of cefixime and dicloxacillin from biological fluids.

[Determination of cefixime blood plasma levels by HPLC]

For comparative study of the pharmacokinetics of Cemidexor (capsules of 100 mg) and Suprax (capsules of 400 mg), a method of HPLC with quantitative determination of cefixime (the active substance in the drugs) in the blood plasma of patients with UV detection was developed. The data teproducibility with an account of the admissibility criterion was observed within the interval of all the concentrations (0.06-10 mcg/ml). The accuracy and correctness of the method also corresponded to the admissibility criteria. The lower limit of the quantitative determimation of the cefexime blood plasma levels was 0.06 mcg/ml. The pharmacokinetics was studied with the open crossed randomized method. The results were used for calculation of the pharmacokinetic parameters required for estimation of the bioequivalence of the drugs. The statistical analysis of the pharmacokinetic parameters showed that Cemidoxor and Suprax were bioequivalent.

Comparative bioavailability study of cefixime (equivalent to 100 mg/5 ml) suspension (Winex vs Suprax) in healthy male volunteers

This investigation was carried out to evaluate the bioavailability of a new suspension formulation of cefixime (100 mg/5 ml), Winex, relative to the reference product, Suprax (100 mg/5 ml) suspension. The bio-availability study was carried out in 24 healthy male volunteers who received a single oral dose (200 mg) of the test (A) and the reference (B) products on 2 treatment days after an overnight fast of at least 10 hours. The treatment periods were separated by a one-week washout period. A randomized, balanced two-way crossover design was used. After dosing, serial blood samples were collected over a period of 16 hours. Plasma concentrations of cefixime were analyzed using a sensitive high-performance liquid chromatographic assay. The pharmacokinetic parameters for cefixime were determined using standard non-compartmental method. The parameters AUC(0-t), AUC(0-infinity), Cmax, Kel, t1/2 and Cmax/AUC(0-infinity) were analyzed statistically using raw and log-transformed data. The time to maximum concentration (tmax) was analyzed using raw data. The parametric 90% confidence intervals of the mean values of the pnfinity harmacokinetic parameters: AUC(0-t), AUC(0-infinity) Cmax, and Cmax/AUC(0-infinity) were within the range 80 - 125% which is acceptable for bioequivalence (using log-transformed data). The calculated 90% confidence intervals based on the ANOVA analysis for the mean test/reference ratios of AUC(0-t), AUC(0-infinity), Cmax, and Cmax/AUC(0-infinity) were 88.93 - 107.10%, 89.09 - 107.11%, 89.63 - 108.58% and 96.85 - 105.29%, respectively. The test formulation was found bioequivalent to the reference formulation with regard to AUC(0-t), AUC(0-infinity), and Cmax using the Schuirmann's two one-sided t-tests. Therefore, the two formulations were considered to be bioequivalent.

Sensitive liquid chromatography–tandem mass spectrometry method for the determination of cefixime in human plasma: Application to a pharmacokinetic study

A sensitive and selective liquid chromatographic-tandem mass spectrometric (LC-MS-MS) method was developed to determine cefixime ((6R,7R)-7-[(Z)-2-(2-amino-4-thiazolyl)-2-(carboxymethoxyimino)acetamido]-8-oxo-3-vinyl-5-thia-1-azabicyclo-[4,2,0]-oct-2-ene-2-carboxylic acid) in human plasma. After a simple protein precipitation using acetonitrile, the post-treatment samples were analyzed on a C(8) column interfaced with a triple quadrupole tandem mass spectrometer. Positive electrospray ionization was employed as the ionization source. The mobile phase consisted of acetonitrile-water-formic acid (40:60:0.5, v/v/v). The analyte and internal standard cefetamet were both detected by use of selected reaction monitoring mode. The method was linear in the concentration range of 0.05-8.0 microg/ml. The lower limit of quantification was 0.05 microg/ml. The intra- and inter-day relative standard deviation across three validation runs over the entire concentration range was less than 12.7%. The accuracy determined at three concentrations (0.05, 0.80 and 7.2 microg/ml for cefixime) was within +/-2.0% in terms of relative error. Each plasma sample was chromatographed within 3.5 min. The method herein described was successfully applied for the evaluation of pharmacokinetic profiles of cefixime capsule in 24 healthy volunteers.