| Nemonoxacin is a novel non-fluorinated quinolone(NFQ),and exhibits inhibition of bacterial DNA gyrase and topoisomerase IV.In vitro,nemonoxacin has demonstrated broad-spectrum activities against clinical isolates.It exhibits potent antibacterial activities against Gram-positive,Gram-negative,anaerobic and atypical pathogens,including antibiotic-resistant pathogens,such as penicillin-and quinolonr-resistant S pneumoniae and methicillin-resistant S aureus(MRSA).Nemonoxacin(1.1 species)is approved to conduct the phase I clinical trial in China by State Food and Drug Administration(SFDA),which include the study of tolerability and the Pharmacokinetic(PK)study of single dose and multi-dose.The PK study shows that the range of tolerance dose of nemonoxacin injection was 25-1250 mg following single dose intravenous infusion in healthy Chinese volunteers,the maximum tolerated dose was 1250 mg and the infusion rate was 0,42 to 5.56 mg/min.The PK study of single dose shows,Cma,were 4.826?g/mL,7.152?g/mL and 11.029?g/mL of 250 mg?500 mg and 750 mg(rate:5.56 mg/min),respectively;mean while AUC0-7h were 17.05 ?g·h/mL?39.30 ?h/mL and 61.98 ?gh/mL,respectively.The mean of t1/2 was 11 h of three injection dose.The drug was predominantly excreted fromkidney,and the accumulative urinary excretion rate was about 70%within 72 h.Further more,the previous PK study and safety evaluation(random,open design)following multi-dose of nemonoxacin for 10 days,with dose of 500mg and 750mg.The results showed that,there were 15 subjects with local reaction adverse event(AE)of Injection site and 6 subjects with unormal result of liver function test.This indicated that the AE may be correlated with lower pH(3.9)and fast infusion rate(5.56mg/min)compared to current study.Based on the results of tolerability and PK study of nemonoxacin injection following single and multi-dose,we designed a a random,two double-blind and placebo-controlled study to further evaluate safety and PK of nemonoxacin in healthy Chinese volunteers.The dose was 500 mg,650 mg and 750 mg,respectively.The infusion rate was 4.17mg/min,while pH was 4.5.By integration of PK information from PK study and the previous pharmacodynamic(PD)results,we conducted PK/PD investigation to analyse the characteristic of nemonoxacin.This will provide the evidence for determing reasonable dosing regiment(dosage?interval?course of treatment and the rate of intervenous drop infusion)of nemonoxacin injection in future phase ? clinical trail.The study included three parts:Part I Development and Validation of the Method for the Determination of Nemonoxacin in Human Plasma and Urine Using LC-MS/MSThe liquid chromatographic-tandem mass spectrometric(LC-MS/MS)method was developed to determine the Nemonoxacin concentration of plasma and urine samples.The samples were collected from the PK studies of Multi-Dose intravenous infusion in Healthy Chinese Volunteers.Waters Alliance 2690 HPLC instrument and Finnigan TSQ Quantum Discovery Max tandem mass spectrometer were applied.Nemonoxacin was separated by Waters Symmetry Shield RP18 column(2.1 by 50mm,5?m)with mobile phase of 0.1%formic acid and acetonitrile(82:18,v/v)and(85:15,v/v)for the determination of plasma and urine samples,respectively.The biological specimens of plasma and urine were pretreated by directed protein precipitation and liquid-liquid extraction,respectively.The internal standard(IS)was gatifloxacin.Both analyte and IS were determined by electrospray ionization and the MS data acquisition via the selected reaction monitoring in positive ion mode,nemonoxacin and IS formed predominately protonation molecular ions[M+H]+ at m/z 372.18 to 354.100 and m/z 376.14 to 332.150,respectively.The lower limit of quantification was 0.005 ?g/mL and the calibration curves were linear in the concentration range of 0.005-1 ?g/mL.The recoveries of nemonoxacin for plasma and urine samples were(98.49 ± 4.69)%and(84.92 ± 6.81)%,the intra-day precision(RSD)were ?5.87%and ?8.30%,the inter-day precision(RSD)were ?6.94%and ?5.43%,and the intra-day accuracy were ranged from 99.27%to 103.75%and 103.52%to 115.94%,respectively.In room temperature,nemonoxacin kept stable over 24 h in plasma and urine samples before treatment,and also stable over 24 h in the post-preparative plasma and urine samples.Nemonoxacin was stable in plasma over three cycles of freeze(-40?)and thawing(room temperature).The recovery of nemonoxacin in plasma and urine samples were(92.14-110.87)%and(83.55-101.95)%,respectively after three months storage in refrigerator(-40?).The method was convenient?fast and high sensitivity,also accorded with the demands of the relevant documents released by SFDA drug evaluation.Part II PK Study and Safety Evaluation of Nemonoxacin following Multi-Dose Intravenous Infusion in Healthy Chinese VolunteersForty-eight subjects(male:female=1:1)were enrolled in a randomized,double blind,multi-dose PK study following consecutive administration of nemonoxacin 500mg,650mg and 750mg for 10 days.This study was designed to evaluate the safety,tolerability and PK profile of nemonoxacin.The plasma and urine samples were collected by schedule to carry out the PK analysis.The PK samples of full course were collected on day 1 and day 10,while trough and peak plasma samples were collected on day 3,day 5,day 8 and day 9,respectively.The LC-MS/MS method was used to determine the concentration of nemonoxacin in the PK samples.PK parameters were calculated using the non-compartment model of WinNolin 5.2.1 software(Pharsight Corp.CA USA).The study shows that Cmax were 7.133?g/mL,8.170 ?g/mL and 9.956 pg/mL following 10 days consecutive administrations of 500mg,650mg and 750 mg of nemonoxacin,,respectively.Mean while AUCO-t(500mg:22h;650mg:21.4h;750mg:21h)were 40.46?g·h/mL,54.17 ?g·h/mL and 71.34 ?g·h/mL,respectively.The statistic analysis showed that,there was no accumulation after 10 days administration of 3 regiments.The statistic analysis of the difference between male and female subjects in PK parameter showed:? In day 1 and day 10 of 500 mg group,the difference in Cmax and AUC0-t had no statistically significant except the Cmin;?In day 1 of 650 mg group,the difference in Cmin?Cmax and AUCO.t were statistically significant,while no statistically significant difference was found in day 10;? In day 1 of 750 mg group,the Cmin values were significantly different,while Cmax and AUC0-t in day 1 and the Cmin,Cmax and AUC0-t in day 10 were no statistical significant different.There were no SAE occurred following multi-dose except 1 case in 650 mg group,2 cases in 750 mg group and 1 case in placebo group which were given symptomatic treatment due to erythema congestivum.Part ? PK/PD Profiles of Nemonoxacin and the Evaluate of the Therapeutic RegimenNemonoxacin is NFQ,the PK/PD parameters are AUC/MIC(ratio by the area under the concentration-time curve and minimal inhibitory concentration)and Cmax/MIC(ratio by the maximum plasma concentration and minimal inhibitory concentration)as other quinolone.Based on the results from our pharmacokinetics studies in Part II and the previous pharmacodynamic study,we estimated the cumulative fraction of response(CFR)of nemonoxacin against each bacteria and the probability of target attainment(PTA)under various MIC level were evaluated using Monte Carlo simulation following multiple administration of three regiments at steady state.The Cmax over the MIC ratio(Cmax/MIC)of 5 and the AUC24h over the MIC ratio(AUC24h/MIC)of 25 were used to assess bacterial eradication,respectively.The study showed that the CFR values of gemifloxacin were 96.5%and 97.9%for AUC24h/MIC and Cmax/MIC,respectively.The PTA values were above 90%when MIC was 1 ?g/mL.The PK/PD analysis suggests that a favorable clinical and bacteriological efficacy could be obtained when using the three regiments. |
PDF Full Text Request