Halloysite nanotubes-based hybrid silica monolithic spin tip for hydrophilic solid-phase extraction of sulbactam, cefoperazone, and cefuroxime in whole blood.

In this study, we proposed a novel method utilizing polyethyleneimine (PEI)-modified halloysite nanotubes (HNTs)-based hybrid silica monolithic spin tip to analyze hydrophilic ß-lactam antibiotics and ß-lactamases inhibitors in whole blood samples for the first time. HNTs were incorporated directly into the hybrid silica monolith via a sol-gel method, which improved the hydrophilicity of the matrix. The as-prepared monolith was further modified with PEI by glutaraldehyde coupling reaction. It was found that the PEI-modified HNTs-based hybrid silica monolith enabled a large adsorption capacity of cefoperazone at 35.7 mg g-1. The monolithic spin tip-based purification method greatly reduced the matrix effect of whole blood samples and had a detection limit as low as 0.1 - 0.2 ng mL-1. In addition, the spiked recoveries of sulbactam, cefuroxime, and cefoperazone in blank whole blood were in the range of 89.3-105.4 % for intra-day and 90.6-103.5 % for inter-day, with low relative standard deviations of 1.3-7.2 % and 4.9-10.5 %, respectively. This study introduces a new strategy for preparing nanoparticles incorporated in a hybrid silica monolith with a high adsorption capacity. Moreover, it offers a valuable tool to monitor sulbactam, cefoperazone, and cefuroxime in whole blood from pregnant women with the final aim of guiding their administration.

Determination of Total and Unbound Meropenem, Imipenem/Cilastatin, and Cefoperazone/Sulbactam in Human Plasma: Application for Therapeutic Drug Monitoring in Critically Ill Patients.

BACKGROUND: Critically ill patients show several pathophysiological alterations that can complicate antibiotic dosing. Hence, there is a strong rationale to individualize anti-infective dosing in these patients by using therapeutic drug monitoring (TDM). The current study aimed to develop and validate a liquid chromatography-tandem mass spectrometry method for the simultaneous determination of total and unbound plasma concentrations of 3 commonly used antibiotics (meropenem, imipenem/cilastatin, and cefoperazone/sulbactam) in the treatment of infections in critically ill patients in China, which could be suitable for routine TDM in hospital laboratories. METHODS: The unbound drug was separated from the bound drug by ultrafiltration. Simple protein precipitation was used for sample preparation. Meropenem, imipenem/cilastatin, cefoperazone/sulbactam, and their corresponding internal standards were then resolved using the Waters CORTECS C18 column. All the compounds were detected using electrospray ionization in the positive/negative ion-switching mode. RESULTS: The calibration curves were linear for all compounds, with correlation coefficients (R) above 0.99 for total concentrations in human plasma and unbound concentrations in the plasma ultrafiltrate. For both total and unbound drugs, the relative errors and intra-assay/interassay relative standard deviations were below 15%. The limit of quantification was 0.05 mcg/mL for both total plasma concentrations and plasma ultrafiltrate concentrations of all compounds. CONCLUSIONS: The method was simple, rapid, and reliable and is currently being used to provide a TDM service to enhance the efficacious use of the 3 antibiotics.

Dual-channel Microchip Electrophoresis with Amperometric Detection System for Rapid Analysis of Cefoperazone and Sulbactam.

A dual-channel microchip electrophoresis (ME) with in-channel amperometric detection was developed for cefoperazone and sulbactam determination simultaneously. In this study, a microelectrode detector was made of gold nanoparticles (GNPs) modified indium tin oxide (ITO)-coated poly-ethylene terephthalate (PET) film. The parameters including detection potential applied on working electrode, buffer concentration and pH value were optimized to improve the detection sensitivity and separation efficiency of cefoperazone and sulbactam. Under the optimal conditions, sensitive detection of cefoperazone and sulbactam was obtained with limits of detection (LODs) (S/N = 3) of 0.52 and 0.75 µg/mL, respectively. The plasma sample, which was from a patient with a brain injury taking Sulperazone, was successfully detected with a simple sample pretreatment process by dual-channel ME amperometric detection. This rapid and sensitive method possesses practical potential in clinical applications, and could provide a guidance for clinical rational drug use.

Plasma and Intrapulmonary Concentrations of ETX2514 and Sulbactam following Intravenous Administration of ETX2514SUL to Healthy Adult Subjects.

ETX2514 is a novel ß-lactamase inhibitor that broadly inhibits Ambler class A, C, and D ß-lactamases. ETX2514 combined with sulbactam (SUL) in vitro restores sulbactam activity against Acinetobacter baumannii ETX2514-sulbactam (ETX2514SUL) is under development for the treatment of A. baumannii infections. The objective of this study was to determine and compare plasma, epithelial lining fluid (ELF), and alveolar macrophage (AM) concentrations following intravenous (i.v.) ETX2514 and sulbactam. Plasma, ELF, and AM concentrations of ETX2514 and sulbactam were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in 30 healthy adult subjects following repeated dosing (ETX2514 [1 g] and sulbactam [1 g] every 6 h [q6h], as a 3-h i.v. infusion, for a total of 3 doses). A bronchoalveolar lavage (BAL) was performed once in each subject at either 1, 2.5, 3.25, 4, or 6 h after the start of the last infusion. Penetration ratios were calculated from area under the concentration-time curve from 0 to 6 h (AUC0-6) values for total plasma and ELF using mean and median concentrations at the BAL fluid sampling times. Respective ELF AUC0-6 values, based on mean and median concentrations, were 40.1 and 39.4 mg · h/liter for ETX2514 and 34.7 and 34.5 mg · h/liter for sulbactam. Respective penetration ratios of ELF to total/unbound plasma concentrations, based on mean and median AUC0-6 values, of ETX2514 were 0.37/0.41 and 0.36/0.40, whereas these same ratio values were 0.50/0.81 and 0.50/0.80 for sulbactam. ETX2514 and sulbactam concentrations in AM were measurable and fairly constant throughout the dosing interval (median values of 1.31 and 1.01 mg/liter, respectively). These data support further study of ETX2514SUL for the treatment of pneumonia caused by multidrug-resistant A. baumannii (This study has been registered at ClinicalTrials.gov under identifier NCT03303924.).

Determination of cefoperazone and sulbactam in serum by HPLC-MS/MS: An adapted method for therapeutic drug monitoring in children.

A rapid, accurate and specific high-performance liquid chromatography-tandem mass spectrometry method has been validated for the simultaneous determination of cefoperazone and sulbactam in a small volume sample for children. A Shim-pack XR-ODS C18 column with gradient elution of water (0.1% formic acid) and acetonitrile (0.1% formic acid) solution was used for separation at a flow rate of 0.3 mL/min. The calibration curves of two analytes in serum showed excellent linearity over the concentration ranges of 0.03-10 µg/mL for cefoperazone, and 0.01-3 µg/mL for sulbactam, respectively. This method involves simple sample preparation steps and was validated according to standard US Food and Drug Administration and European Medicines Agency guidelines in terms of selectivity, linearity, detection limits, matrix effects, accuracy, precision, recovery and stability. This assay can be easily implemented in clinical practice to determine concentrations of cefoperazone and sulbactam in children.

High-Dose Ampicillin-Sulbactam Combinations Combat Polymyxin-Resistant Acinetobacter baumannii in a Hollow-Fiber Infection Model.

Acinetobacter baumannii is emerging with resistance to polymyxins. In 24-h time-kill experiments, high-dose ampicillin-sulbactam in combination with meropenem and polymyxin B achieved additivity or synergy against 108 CFU/ml of two clinical A. baumannii isolates resistant to all three drugs (maximum reductions, 1.6 and 3.1 logs). In a 14-day hollow-fiber infection model, high-dose ampicillin-sulbactam (8/4 g every 8 h, respectively) in combination with meropenem (2 g every 8 h) and polymyxin B (1.43 mg/kg of body weight every 12 h with loading dose) resulted in rapid (96 h) eradication of A. baumannii.

The pharmacokinetics of ampicillin-sulbactam in anuric patients: dosing optimization for prophylaxis during cardiovascular surgery.

Background The administration of antibiotic prophylaxis during cardiothoracic surgery can reduce the rate of surgical site infections. Trials of cardiothoracic antibiotic prophylaxis have found it to be beneficial in preventing postoperative wound infections. Objective To determine the more appropriate timing of repeated doses of ampicillin-sulbactam to maintain adequate antibiotic concentrations during cardiovascular surgery in anuric patients. Method Five adult anuric dialysis patients who received ampicillin-sulbactam during cardiovascular surgery at Kagoshima University Hospital, the total plasma concentrations of ampicillin and sulbactam were monitored after ampicillin (1 g)-sulbactam (0.5 g) administration. Pharmacokinetic parameters were estimated and used to predict the free plasma concentrations of ampicillin and sulbactam. Results The mean values for the volume of distribution, total clearance, elimination rate constant and the elimination half-life for ampicillin were 8.9 ± 2.4 L, 1.69 ± 0.93 L/h, 0.180 ± 0.059 h(-1) and 4.23 ± 1.48 h, respectively. The pharmacokinetic parameters were similar to those of sulbactam. When ampicillin (1 g)-sulbactam (0.5 g) was intravenously administered at 8, 12 and 24 h intervals, the predicted free trough plasma concentrations of ampicillin were 28.72, 12.06 and 1.25 µg/mL, respectively. Conclusion We suggest that ampicillin (1 g)-sulbactam (0.5 g) should be intravenously administered every 12 h in order to maintain a free ampicillin concentration of more than 12 µg/mL in anuric patients during cardiovascular surgery.

Pharmacokinetics of cefoperazone/sulbactam in critically ill patients receiving continuous venovenous hemofiltration.

PURPOSE: Cefoperazone/sulbactam (CFP/SUL) is a ß-lactam/ß-lactamase inhibitor combination with little data available for the development of effective dosing guidelines during continuous renal replacement therapy. This study aimed to investigate the pharmacokinetics (PK) of cefoperazone/sulbactam in critically ill patients on continuous venovenous hemofiltration (CVVH). METHODS: A prospective, single-center, and open-label study was conducted. Critically ill patients receiving CVVH with 3 g cefoperazone/sulbactam (2.0/1.0 g) intravenously every 8 h were recruited. Serial blood and ultrafiltrate samples were paired collected for initial dose (occasion 1) and steady state (occasion 2). PK was assessed by non-compartmental analysis, and pharmacodynamics (PD) was evaluated by the percent of time for which drug concentrations exceed the minimum inhibitory concentration (%T >MIC). RESULTS: Total fourteen patients were enrolled. Volume of distribution at steady state (V ss) of cefoperazone and sulbactam for initial doses (20.8 ± and 28.4 L, respectively) increased significantly compared with those in healthy volunteers (P = 0.009 for CFP, P = 0.030 for SUL). Both cefoperazone and sulbactam showed significantly lower total clearance (CLt) (46.2 and 117.6 mL/min, respectively) compared with healthy volunteers (P = 0.000 for CFP, P = 0.017 for SUL). There is no significant difference in PK between occasion 1 and occasion 2 (P > 0.05). For occasion 1, mean CVVH clearance accounted for 34.3 and 33.9 % for CLt of cefoperazone and sulbactam, respectively. The minimum PD target of 60%T >MIC was achieved in seven of eight patients. For occasion 2, eight of nine patients achieved cefoperazone concentrations that were above the MIC for the entire dosing interval. CONCLUSIONS: PK of cefoperazone/sulbactam was altered in critically ill patients undergoing CVVH. Therapeutic drug monitoring would be recommended to individualize the dose regimen.

Pharmacokinetics of Prophylactic Ampicillin-Sulbactam and Dosing Optimization in Patients Undergoing Cardiovascular Surgery with Cardiopulmonary Bypass.

UNLABELLED: Antibiotic concentrations must be maintained at an adequate level throughout cardiovascular surgery to prevent surgical site infection. This study aimed to determine the most appropriate timing for intraoperative repeated dosing of ampicillin-sulbactam, a commonly used antibiotic prophylaxis regimen, to maintain adequate concentrations throughout the course of cardiovascular surgery with cardiopulmonary bypass (CPB). The total plasma concentrations of ampicillin were monitored in 8 patients after ampicillin (1 g)-sulbactam (0.5 g) administration via initial intravenous infusion and subsequent CPB priming. Pharmacokinetic parameters were estimated and used to predict the free plasma concentrations of ampicillin. The mean values for the volume of distribution, elimination rate constant, elimination half-life, and total clearance of ampicillin were 15.8±4.1 L, 0.505±0.186 h(-1), 1.52±0.47 h, and 7.72±2.72 L/h, respectively. When ampicillin (1 g)-sulbactam (0.5 g) was intravenously administered every 3, 4, 6, and 12 h after the start of CPB, the predicted free trough plasma concentrations of ampicillin were 15.20, 8.25, 2.74, and 0.13 µg/mL, respectively. Therefore, an every-6-h regimen was needed to maintain the free ampicillin concentration at more than 2 µg/mL during cardiovascular surgery with CPB. We suggest that the dose and dosing interval for ampicillin-sulbactam should be adjusted to optimize the efficacy and safety of treatment, according to the minimum inhibitory concentrations for methicillin-sensitive Staphylococcus aureus isolates at each institution. REGISTRATION NUMBER: UMIN000007356.

Drug concentrations in the serum and cerebrospinal fluid of patients treated with cefoperazone/sulbactam after craniotomy.

BACKGROUND: To identify changes in cefoperazone/sulbactam penetration into cerebrospinal fluid (CSF) after craniotomy and to investigate preliminarily whether cefoperazone/sulbactam CSF concentration can reach therapeutic level when administered intravenously after neurosurgical operation. METHODS: Neurosurgical patients with an indwelling ventricular drainage pipe who received prophylactic cefoperazone/sulbactam for the treatment of intracranial infection were received a cefoperazone/sulbactam 2:1, 3.0-g infusion for 3 hours every 6 hours for 24 h. Venous blood and CSF specimens were collected to determine cefoperazone/sulbactam concentrations. RESULTS: The cefoperazone and sulbactam concentrations in serum were highest at the second hour (237.54 ± 336.72 mg/L and 66.52 ± 80.38 mg/L, respectively) and then decreased. The cefoperazone and sulbactam concentrations in CSF were highest at the 4th hour (39.22 ± 75.55 mg/L and 6.24 ± 8.35 mg/L, respectively) and then decreased. CSF penetration measured by the ratio of peak concentrations (CSF/serum) was 8.6% ± 7.2% for cefoperazone and 13.5% ± 11.9% for sulbactam, CSF penetration measured by the ratio of trough concentrations (CSF/serum) was 13.4% ± 5.3% for cefoperazone and 106.5% ± 87.5% for sulbactam. CSF penetration represented by the ratio of area under the curve (AUC) of CSF and serum was 14.5% for cefoperazone and 22.6% for sulbactam. Neurosurgical impairment of the blood-brain barrier may improve the CSF penetration of these drugs, but it is difficult to reach the MIC90 of resistant bacteria. If single intravenous administration time was extended to 3 hours, the serum concentrations of drugs were able to meet the PK/PD standard (T> MIC%> 50%) for treating common, highly resistant bacteria. CONCLUSIONS: The CSF penetration of cefoperazone/sulbactam may be enhanced after neurosurgical impairment of the blood-brain barrier. This study is a pilot research of cefoperazone/sulbactam using in neurosurgical individuals, However, it needs to be confirmed by further large-scale studies.

Population pharmacokinetic-pharmacodynamic target attainment analysis of sulbactam in patients with impaired renal function: dosing considerations for Acinetobacter baumannii infections.

UNLABELLED: This study aimed to perform a pharmacokinetic (PK)-pharmacodynamic (PD) target attainment analysis of sulbactam against Acinetobacter baumannii in patients with impaired renal function. The PK data (188 plasma samples and 27 urine samples) were modeled simultaneously. The mean population parameters were CLr (l/h) = 0.0792 × CLcr (ml/min), CLnr (l/h) = 2.35, Vc (l) = 12.2, Q (l/h) = 4.68 and Vp (l) = 4.44, where CLr and CLnr are the renal and non-renal clearances, Vc and Vp are the distribution volumes of the central and peripheral compartments and Q is intercompartmental clearance. The creatinine clearance (CLcr) was the most significant covariate. The determined MIC of sulbactam against A. baumannii clinical isolates (n = 27) was 0.75-6.0 µg/ml with MIC50 and MIC90 of 1 and 4 µg/ml, respectively. For sulbactam regimens, a Monte Carlo simulation estimated the probabilities of attaining the bactericidal target (60% of the time above the MIC) and determined the PK-PD breakpoints (the highest MICs at which the probabilities were 90% or more). In a patient with a CLcr of 15 ml/min, a regimen of 1 g twice daily achieved a 90% or more probability against the A. baumannii isolate population; however, 2 g four times daily was needed for a 90% or more probability in a patient with a CLcr of 90 ml/min. The results of the PK-PD target attainment analysis are useful when choosing the sulbactam regimen based on the CLcr of the patient and the susceptibility of A. baumannii. REGISTRATION NUMBER: UMIN000007356.

Population pharmacokinetics of ampicillin and sulbactam in patients with community-acquired pneumonia: evaluation of the impact of renal impairment.

AIMS: The aims of this study were to develop a population pharmacokinetic (PK) model of ampicillin and sulbactam, to identify patient characteristics influencing the PK, and to explore the relationship between dose regimen and degree of renal impairment with exposure and time above minimum inhibitory concentration (MIC). METHODS: This analysis was performed on PK data for ampicillin and sulbactam and MIC data from a clinical trial in Japanese patients with community acquired pneumonia. Simulations were performed to investigate the effects of different dosing intervals on exposure and time above MIC in various degrees of renal impairment. RESULTS: The plasma concentrations from 47 patients were adequately described by a two compartment model with simultaneous fit of ampicillin and sulbactam PK data, where creatinine clearance on clearance and body weight on volume in the peripheral compartment were identified as covariates for both drugs. Creatinine clearance contributed to reducing inter-individual variability of clearance by 16%. Mean clearance (inter-individual variability) for ampicillin and sulbactam was estimated to be 10.7 l h(-1) (14.8%) and 10.4 l h(-1) (15.2%), respectively. The time above MIC for each pathogen was generally > 50% of the treatment period. Simulations for exposure and time above MIC supported currently recommended dose adjustments. CONCLUSIONS: This study provided a PK model for ampicillin and sulbactam, the time above MICs for identified pathogens and associated simulation results. These findings provide useful information and augment evidence for the established dosage regimens in patients with various degrees of renal impairment.

Pharmacodynamics modeling to optimize dosage regimens of sulbactam.

The aim of this study was to reveal population pharmacokinetics and assess the efficacies of various dosage regimens of sulbactam in terms of the probability of target attainment with this agent over a range of MICs. Monte Carlo simulations were performed to determine the probability of attaining specific pharmacodynamic targets. The results indicated that a regimen consisting of a 4-h infusion of 3 g of sulbactam every 8 h would be an alternative treatment option for less-susceptible pathogens.

Pharmacokinetics of ampicillin-sulbactam and the renal function-based optimization of dosing regimens for prophylaxis in patients undergoing cardiovascular surgery.

UNLABELLED: Surgical site infections are a major cause of postoperative morbidity and mortality in cardiovascular surgery. Proper antibiotic prophylaxis can reduce the rate of such infections, but the concentration of antibiotic must be maintained at an adequate level throughout the operation. This study aimed to use renal function to determine the most appropriate timing for intraoperative repeated dosing of ampicillin-sulbactam, a commonly used prophylactic antibiotic, to maintain adequate concentrations throughout the course of surgery. The mean volume of distribution, elimination rate constant, elimination half-life, and total clearance of ampicillin were 13.2 l, 0.652 h⁻¹, 1.32 h, and 8.45 l/h, respectively. A statistically significant (P < 0.0001) correlation (r = 0.771) was observed between the total clearance of ampicillin and creatinine clearance of the patients. Plasma concentrations of ampicillin were simulated with the pharmacokinetic parameters obtained. We developed a nomogram for adjusting the dosing interval according to renal function and predicted ampicillin trough concentrations. We revealed the best dosage and dosing interval for cardiovascular surgery by analyzing the perioperative pharmacokinetics of ampicillin-sulbactam administered prophylactically. We suggest that the dosage and dosing interval for ampicillin-sulbactam should be adjusted to optimize treatment efficacy and safety, on the basis of the MIC90 of methicillin-sensitive Staphylococcus aureus (MSSA) in each institution. TRIAL REGISTRATION: UMIN000007356.

Pharmacokinetics of ampicillin/sulbactam in critically ill patients with acute kidney injury undergoing extended dialysis.

BACKGROUND AND OBJECTIVES: The fixed antibacterial combination of ampicillin and sulbactam is frequently used for various infections. Intact kidneys eliminate approximately 71% of ampicillin and 78% of sulbactam. Patients on thrice-weekly low-flux hemodialysis exhibit an ampicillin t(1/2) of 2.3 hours on and 17.4 hours off dialysis. Despite its frequent use in intensive care units, there are no available dosing recommendations for patients with AKI undergoing renal replacement therapy. The aims of this study were to evaluate the pharmacokinetics of ampicillin/sulbactam in critically ill patients with AKI undergoing extended dialysis (ED) and to establish a dosing recommendation for this treatment method. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Twelve critically ill patients with anuric AKI being treated with ED were enrolled in a prospective, open-label, observational pharmacokinetic study. Pharmacokinetics after a single dose of ampicillin/sulbactam (2 g/1 g) was obtained in 12 patients. Multiple-dose pharmacokinetics after 4 days of twice-daily ampicillin/sulbactam (2 g/1 g) was obtained in three patients. RESULTS: The mean dialyzer clearance for ampicillin/sulbactam was 80.1 ± 7.7/83.3 ± 12.1 ml/min. The t(1/2) of ampicillin and sulbactam in patients with AKI undergoing ED were 2.8 ± 0.8 hours and 3.5 ± 1.5 hours, respectively. There was no significant accumulation using a twice-daily dosage of 2 g/1 g ampicillin/sulbactam. CONCLUSIONS: Our data suggest that in patients treated with ED using a high-flux dialyzer (polysulphone, 1.3 m(2); blood and dialysate flow, 160 ml/min; treatment time, 480 minutes), a twice-daily dosing schedule of at least 2 g/1 g ampicillin/sulbactam, with one dose given after ED, should be used to avoid underdosing.

Does ampicillin-sulbactam cause false positivity of (1,3)-beta-D-glucan assay? A prospective evaluation of 15 patients without invasive fungal infections.

The purpose of this study was to investigate the interaction between intravenous ampicillin-sulbactam treatment and (1,3)-beta-D-glucan (BDG) assay. Fifteen patients with a median age of 60 (16-81) without known risk factors for invasive fungal infections who received a daily dose of 3×2g ampicillin-sulbactam monotherapy from different batches were included in the study. Thirteen patients had soft tissue infections. The 5 of 13 patients who went under surgery had surgical dressings. Serum samples were obtained both before and after antibiotic infusion on the first, third, seventh and tenth days of an ampicillin-sulbactam treatment course. BDG was assayed using the Fungitell kit (Associates of Cape Cod, East Falmouth, MA, USA) according to manufacturers' specifications. All serum samples were also tested for galactomannan (GM) antigenemia by Platelia Aspergillus ELISA (Bio-Rad Laboratories, Marnes-la-Coquette, France). A total of 37 of 117 serum samples were positive for BDG at a threshold of 80pg ml(-1) . Seven of 37 BDG positive serum samples had a GM index ≥0.5. When a cutoff value of ≥0.5 was used for GM positivity, 16 (13.3%) serum samples were positive. For a cutoff value of ≥0.7, eight (6.6%) serum samples were positive. There were no statistically significant differences in the median BDG levels (P=0.47) or median GM indices (P =0.28) of the various sampling times. None of the SAM vials tested positive for BDG or GM. After ruling out fungal infections and all known potential causes of false BDG positivity, environmental contamination remained possible cause of BDG reactivity. We did not observe any significant association of ampicillin-sulbactam administration and positive assays for BDG or GM.

[Assessment of efficacies of imipenem, cefoperazone-sulbactam and cefepime in rats with experimental thigh abscess model with multidrug resistant and susceptible Acinetobacter baumannii strains]. / Sefoperazon-sulbaktam, imipenem ve sefepimin antibiyoterapi etkinliklerinin çogul dirençli ve duyarli acinetobacter baumannii ile olusturulan deneysel ikili apse modelinde karsilastirilmasi.

Imipenem, cefaperazon-sulbactam and cefepime are the antibiotics of choice for the treatment of soft tissue infections due to Acinetobacter baumannii. In this study, it was aimed to determine the invivo and invitro efficacy of, these antibiotics against drug susceptible and multidrug resistant A.baumannii in an experimental abscess model. Abscess models were established in Wistar-Albino type female rats. Susceptibility tests were performed by E-test. Rats were divided randomly into four groups with eight rats in one group. Standard absorbent paper discs containing 6 log10 CFU microorganisms were used to form an abscess model. The first group was regarded as the control group and the other three groups were the study group each treated with one of the test antibiotics. Cardiac blood samples for serum antibiotic efficacy test, were obtained on the fourth day of treatment and 30 minutes after the last dose. The number of live bacteria at the area of infection was determined by colony count method. All of the three antibiotics reached sufficient concentration in sera of rats and there were no statistically important difference between the efficacies of these antibiotics (p= 0.778). In all of the antibiotic-treated groups, the weight of the abscess material were less, macroscopic views were smaller and the colony counts per gram of abscess tissue were less than the control group (p< 0.001). All antibiotics were effective against susceptible and resistant strains in vitro. No resistance was detected against imipenem, cefaperazon-sulbactam and cefepime in the course of therapy. Cefaperazone-sulbactam and cefepime were as effective as imipenem against susceptible and multi-drug resistant A.baumannii both in vivo and in vitro. Since irrational use of extended spectrum cephalosporins are frequently associated with the emergence of carbapenem resistant strains, the use of relatively narrow spectrum antibiotics should better be considered in the empirical treatment of A.baumannii infections.

Simultaneous analysis of amoxicillin and sulbactam in human plasma by HPLC-DAD for assessment of bioequivalence.

A simple and accurate high-performance liquid chromatography with diode array detection-based (HPLC-DAD) method has been developed and validated for simultaneous determination of amoxicillin and sulbactam in human plasma. Sample preparation was involved in protein precipitation with acetonitrile followed by one-step extraction procedure. Chromatographic separation was achieved on a C18 column with an isocratic mobile phase consisting of water (containing 30 mM potassium dihydrogen phosphate, pH 2.8) and acetonitrile. The detection wavelengths of a diode array detector were set at 210 nm for amoxicillin and sulbactam, and 263 nm for the internal standard (cefadroxil). The method was validated for linearity, accuracy, precision, and stability. The calibration curve was linear from 0.163 to 14.7 µg/mL with correlation coefficient squared of 0.9991 for amoxicillin and 0.250-15.0 µg/mL with correlation coefficient squared of 0.9988 for sulbactam using 500 µL plasma samples. The lower limit of quantification was 0.163 and 0.250 µg/mL for amoxicillin and sulbactam, respectively. The imprecisions of intra- and inter-day validations for amoxicillin and sulbactam were <11% and their accuracies (%) were within the range of 95.4-105.7%. Mean recoveries were 75.9, 72.8, and 70.0% for amoxicillin, sulbactam, and cefadroxil, respectively. The established method was successfully applied to a bioequivalence study of two combination formulations of amoxicillin and sulbactam pivoxil in healthy male volunteers.

Liquid chromatography/tandem mass spectrometry assay for the simultaneous determination of cefoperazone and sulbactam in plasma and its application to a pharmacokinetic study.

A rapid and highly sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for simultaneous determination of cefoperazone sodium and sulbactam sodium in human plasma was developed. The analytes and internal standard (IS), cefuroxime sodium, were extracted from human plasma via liquid-liquid extraction with ethyl acetate and separated on a Waters Xterra C18 column within 3.5 min. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in selected reaction monitoring (SRM) and negative ion mode. The precursor to product ion transitions monitored for cefoperazone, sulbactam and IS were m/z 644.1→528.0, 232.1→140.0, and 423.0→362.0, respectively. The assay was validated in the linear range of 0.1-20 µg/mL for cefoperazone and 0.02-4 µg/mL for sulbactam. The intra- and inter-day precisions (CV%) were within 8.39% for each analyte. The recoveries were greater than 87.3% for cefoperazone and 87.2% for sulbactam. Each analyte was found to be stable during all sample storage, preparation and analytical procedures. The method was successfully applied in a pharmacokinetic study of Sulperazon injection in six hospital-acquired pneumonia (HAP) patients.

Pharmacokinetic study of sulbactomax.

We have evaluated pharmacokinetics of a fixed dose combination (FDC) of ceftriaxone and sulbactam (2:1) or sulbactomax in eight healthy volunteers. A 1.5 g dose of sulbactomax, 1 g dose of ceftriaxone and 0.5 g sulbactam were given intravenously in a balanced two-ways cross-over study. Serially collected plasma sample was analyzed for ceftriaxone and sulbactam by high performance liquid chromatography (HPLC). The mean peaks of ceftriaxone and sulbactam concentrations in plasma were 152.06+/-6.65 microg/ml and 21.32+/-1.80 microg/ml, respectively and plasma half-lives for ceftriaxone and sulbactam were 5.2+/-0.35 hr and 0.94+/-0.038 hr, respectively. The AUC0-24 for ceftriaxone and sulbactam was 760.16+/-27.68 microg.hr/ml and 20.74+/-2.34 microg.hr/ml, respectively, with elimination rate constant of 0.133+/-0.009 hr(-1) and 0.732+/-0.029 hr(-1), respectively. The kinetics of ceftriaxone and sulbactum did not change in combination as compared to the alone treatment. Also, concentration of the ceftriaxone after 24 hr is higher than the minimum inhibitory concentration (MIC) of the most of the gram positive and gram negative bacteria indicating that one dose in a day is sufficient to treat the disease caused by these organisms.