Quantitation of carbenicillin disodium, cefazolin sodium, cephalothin sodium, nafcillin sodium, and ticarcillin disodium by high-pressure liquid chromatography

Clinical Outcomes of an Innovative Cefazolin Delivery Program for MSSA Infections in OPAT

Cefazolin is a recommended treatment for methicillin-susceptible Staphylococcus aureus (MSSA) infections that has been successfully used in outpatient parenteral antibiotic therapy (OPAT) programs. The aim of this study was to assess the clinical outcomes of cefazolin delivered each day (Group 24) vs. every two days (Group 48) for MSSA infections in OPAT programs. It was a prospective observational study with retrospective analysis of a cohort of MSSA infections attended in OPAT. The primary outcome was treatment success, defined as completing the antimicrobial regimen without death, treatment discontinuation, or readmission during treatment and follow-up. A univariate and multivariate logistic regression model was built. A two-sided p < 0.05 was considered statistically significant. Of the 149 MSSA infections treated with cefazolin 2 g/8 h in OPATs, 94 and 55 patients were included in the delivery Group 24 and Group 48, respectively. Treatment failure and unplanned readmission rates were similar in both groups (11.7% vs. 7.3% p = 0.752 and 8.5% vs. 5.5% p = 0.491). There was a significant increase in vascular access complications in Group 24 (33.0%) with respect to Group 48 (7.3%) (p < 0.001). Treating uncomplicated MSSA infection with cefazolin home-delivered every two days through an OPAT program is not associated with an increased risk of treatment failure and entails a significant reduction in resource consumption compared to daily delivery.

Cephalothin: Review of Characteristics, Properties and Status of Analytical Methods

BACKGROUND

Cephalothin (CET), a first generation cephalosporin, is the most efficient cephalosporin against resistant microorganisms. Many studies found in literature and pharmacopeias proposes analytical methods and, as most commonly, HPLC and microbiological assays.

OBJECTIVE

This paper shows a brief review of analytical method to quantify CET with a green analytical chemistry approach.

METHODS

The research data were collected from the literature and official compendia.

RESULTS

Most of the analytical methods to determine CET were performed by HPLC and agar diffusion in pharmaceuticals, blood, urine or water. Other analytical methods were found, as UV, Vis, iodometry, fluorimetry, IR/Raman, electrochemical among others, but, in less quantity. One important aspect is that these methods use organic and toxic solvents like methanol and acetonitrile, and only about 4% of the methods found uses water as solvent.

CONCLUSIONS

In this way, researches about analytical methods focused on green analytical chemistry for CET are of great importance and very relevant to optimize its analysis in pharmaceutical industries and to guarantee the quality of the product. More than just the development of new techniques it is possible to enhance of the ones that already exists applying the green analytical chemistry principles. In this way, it will be possible to reduce the environment impacts caused by these analytical procedures.

HIGHLIGHTS

This work shows a brief review of literature and pharmacopeias of analytical methods to quantify CET. Its quality control can be updated to meet the needs of current analytical chemistry and to fit into sustainable and eco-friendly analyzes.

Pharmacokinetics of Intermittent Intraperitoneal Cefazolin in Continuous Ambulatory Peritoneal Dialysis Patients

Objective

To investigate the pharmacokinetic parameters of intermittent intraperitoneal (IP) cefazolin, and recommend a cefazolin dosing regimen in continuous ambulatory peritoneal dialysis (CAPD) patients.

Design

Prospective nonrandomized open study.

Setting

CAPD outpatient clinic in Albany, New York.

Patients

Seven volunteer CAPD patients without peritonitis. Three of the patients were nonanuric while 4 were anuric.

Interventions

Cefazolin (15 mg/kg total body weight) was given to each patient during the first peritoneal exchange. Blood and dialysate samples were collected at times 0, 0.5, 1, 2, 3, 6 (end of the first antibiotic-containing dwell), 24, and 48 hours after the administration of IP cefazolin. Urine samples were collected in nonanuric patients over the study period.

Results

The mean ± SD amount of cefazolin dose absorbed from the dialysate after the 6-hour dwell was 69.7% ± 8.0% of the administered dose. The cefazolin absorption rate constant from dialysate to serum was 0.21 ± 0.1 /hr (absorption half-life 3.5 ± 0.8 hr). The mean serum concentrations reached at 24 and 48 hours were 52.4 ± 3.7 mg/L and 30.3 ± 5.9 mg/L, respectively. The mean dialysate cefazolin concentrations reached at 24 and 48 hours were 15.1 ± 3.4 mg/L and 7.9 ± 1.4 mg/L, respectively. The cefazolin serum elimination rate constant was 0.02 ± 0.01 /hr (elimination half-life 31.5 ± 8.8 hr). The total cefazolin body clearance was 3.4 ± 0.6 mL/min. In the 3 nonanuric patients the mean renal clearance of cefazolin was 0.6 ± 0.4 mL/min. The peritoneal clearance of cefazolin was 1.0 ± 0.3 mL/min. The systemic volume of distribution of cefazolin was 0.2 ± 0.05 L/kg. No statistical difference was detected in pharmacokinetic parameters between anuric and nonanuric patients, although this may be due to the small number of patients in each group.

Conclusion

A single daily dose of cefazolin dosed at 15 mg/kg actual body weight in CAPD patients is effective in achieving serum concentration levels greater than the minimum inhibitory concentration for sensitive organisms over 48 hours, and dialysate concentration levels over 24 hours. Caution is warranted in extrapolation of dosing recommendations to patients who maintain a significant degree of residual renal function.

Review for Analytical Methods for the Determination of Sodium Cephalothin

Infections are the second leading cause of global morbidity and mortality, therefore it is highly important to study the antimicrobial agents such as cephalosporins. Cephalothin, an antimicrobial agent that belongs to the class of cephalosporins, has bactericidal activity and it is widely used in the Brazilian health system. In literature, some analytical methods are found for the identification and quantification of this drug, which are essential for its quality control, which ensures maintaining the product characteristics, therapeutic efficacy and patient's safety. The aim of this article is to review the available information on analytical methods for cephalothin. Thus, this study presents a literature review on cephalothin and the analytical methods developed for the analysis of this drug in official and scientific papers. It is essential to note that most of the developed methods used toxic and hazardous solvents, which makes necessary industries and researchers choose to develop environmental-friendly techniques, which will contribute to the harmonization of science, human, and environmental health.

Identification, Isolation, and Characterization of a New Degradation Impurity in Nafcillin Sodium

A new degradant of Nafcillin Sodium was found at a level of 1.8% w/w during the gradient reversed-phase HPLC analysis in stability storage samples. This impurity was identified by LC-MS and was characterized by (1)H-NMR, (13)C-NMR, LC/MS/MS, elemental analysis, and IR techniques. Based on the structural elucidation data, this impurity was named as N-[(2S)-2-carboxy-2-{[(2-ethoxynaphthalen-1-yl)carbonyl]amino}ethylidene]-3-({N-[(2-ethoxynaphthalen-1-yl)carbonyl]glycyl}sulfanyl)-D-valine. This impurity was prepared by isolation and was co-injected into the HPLC system to confirm the retention time. To the best of our knowledge, this impurity has not been reported elsewhere. The identification and structural elucidation of this degradant impurity has been discussed in detail.

Stability of cefazolin sodium in polypropylene syringes and polyvinylchloride minibags

BACKGROUND

Cefazolin is a semisynthetic penicillin derivative with a narrow spectrum of activity covering some gram-positive organisms and a few gram-negative aerobic bacteria.

OBJECTIVE

To determine the physical and chemical stability of cefazolin sodium reconstituted with sterile water for injection and stored in polypropylene syringes or diluted with either 5% dextrose in water (D5W) or 0.9% sodium chloride (normal saline [NS]) and stored in polyvinylchloride (PVC) minibags.

METHODS

Reconstituted solutions of cefazolin (100 or 200 mg/mL) were packaged in polypropylene syringes. More dilute solutions (20 or 40 mg/mL) were prepared in D5W or NS and packaged in PVC minibags. For each concentration-diluent-container combination, 3 containers were designated for each day of analysis (days 7, 14, 21, and 30). Containers were stored under refrigeration (5°C) with protection from light until the designated day of analysis, at which time one 5-mL sample was collected from each the designated container. The designated containers were then stored at room temperature (21°C to 25°C) with exposure to light for an additional 72 h, and additional samples were drawn. The samples were assayed using a validated, stability-indicating high-performance liquid chromatography method. The colour and clarity of the solutions, as well as their pH, were also monitored on each sampling day.

RESULTS

All samples remained clear for the duration of the study; they had a slight yellow colour that darkened over time, and there was an increase in pH. Solutions diluted with sterile water for injection and stored in polypropylene syringes retained at least 94.5% of the initial concentration after 30 days of refrigerated storage and at least 92.1% after an additional 72 h at room temperature with exposure to light. Samples diluted in D5W or NS and stored in PVC minibags retained at least 95.8% of the initial concentration after 30 days of refrigerated storage and at least 91.8% after an additional 72 h at room temperature with exposure to light.

CONCLUSIONS

Cefazolin at various concentrations stored in polypropylene syringes or PVC minibags was stable for up to 30 days with storage at 5°C with protection from light, followed by an additional 72 h at 21°C to 25°C with exposure to light.

Stability of commonly used antibiotic solutions in an elastomeric infusion device

BACKGROUND

The Accufuser silicone-based elastomeric infusion device has recently been approved for the Canadian market.

OBJECTIVE

To evaluate the stability of 5 antibiotics (cefazolin, ceftazidime, ceftriaxone, clindamycin, and vancomycin) in either 5% dextrose in water (D5W) or 0.9% sodium chloride in water (NS) after storage in Accufuser disposable silicone balloon infusers.

METHODS

The study drugs were reconstituted, according to the manufacturers' directions, in polyvinyl chloride minibags with either D5W or NS, at 2 different concentrations. The resulting solutions were transferred to disposable silicone balloon infusers for storage at 4°C or at room temperature (23°C). The concentration of each drug in each solution was determined by validated stability-indicating liquid chromatographic methods after storage for 14 to 31 days.

RESULTS

Solutions of ceftriaxone in either diluent retained more than 95.2% of the initial concentration for 2 days at room temperature and more than 91.6% of the initial concentration for 14 days at 4°C. Solutions of cefazolin in D5W or NS retained more than 90% of the initial concentration for at least 3 days at room temperature and for at least 26 days at 4°C. Solutions of ceftazidime in D5W or NS retained more than 90% of the initial concentration for only 1 day when stored at room temperature and for at least 4 days at 4°C. Solutions of clindamycin or vancomycin in D5W or NS retained 90% of the initial concentration for at least 7.5 days at room temperature and at least 90% of the initial concentration for at least 27.8 days at 4°C.

CONCLUSIONS

Previously reported expiration dates for solutions stored in elastomeric infusion devices were not based on 95% confidence intervals and were often longer than expiration dates determined from the studies reported here, which are based on 95% confidence intervals. Comparison of the observed concentrations remaining between previously published studies and the studies reported here indicates that the Accufuser elastomeric infusion device did not adversely affect the stability of these drugs.

Pharmacokinetics of intraperitoneal cefazolin and ceftazidime coadministered to CAPD patients

PURPOSE

Guidelines for empiric treatment of PD-related peritonitis published in 2000 recommend concurrent intraperitoneal (IP) cefazolin and ceftazidime. The pharmacokinetics (PK) of these agents combined have not been studied. This study was designed to determine the PK of combined IP cefazolin and ceftazidime in CAPD patients.

DESIGN

Prospective PK study in seven non-infected CAPD patients.

PROCEDURES

Patients had a peritoneal equilibration test (PET), then received one IP dose of cefazolin and ceftazidime (15 mg/kg each) co-administered over a 4-hour dwell, then performed three CAPD exchanges over the next 16 hours. Serum and dialysate samples collected over the 20-hour study period were assayed for drug concentrations by HPLC.

OUTCOME MEASURES

PK parameters.

STATISTICAL METHODS

Correlations were tested between PET and PK parameters using the Pearson-product correlation coefficient.

MAIN FINDINGS

Serum cefazolin and ceftazidime levels exceeded the minimum inhibitory concentrations for susceptible organisms (8 mg/L) throughout the 20 hour study period. Mean cefazolin and ceftazidime PK parameters included: bioavailability, 71% and 63%; elimination rate constant, 0.031 and 0.045 h -1 ; total clearance, 5.8 and 16.0 ml/min; peritoneal clearance, 1.6 and 3.9 ml/min; renal clearance, 2.3 and 3.9 ml/min, respectively. Predictive equations suggest that 1000 mg IP of cefazolin and of ceftazidime every 24 hours would produce average steady-state trough serum cefazolin and ceftazidime concentrations of 70 +/- 52 mg/L and 17 +/- 7 mg/L, respectively. There was no correlation between PET and PK parameters.

CONCLUSIONS

Co-administration did not adversely affect the PK of either agent. IP cefazolin and ceftazidime (15 mg/kg) produced adequate serum and dialysate concentrations in CAPD patients for 20 hours. PK predictions suggest that most patients would achieve adequate cefazolin and ceftazidime concentrations with 1000 mg IP once-daily. Anuric patients and those with significant residual renal function may require a more individualized approach.

Determination of unbound cephalothin in rat blood by on-line microdialysis and microbore liquid chromatography

A method of analysis for the determination of unbound cephalothin in rat blood has been developed. The method was fully automated using an on-line microdialysis procedure. A microdialysis probe was inserted into the jugular vein/right atrium of male Sprague-Dawley rats to examine the unbound cephalothin level in the rat blood after cephalothin administration (50 mg/kg, i.v.). Dialysates were directly input to a liquid chromatographic system using an on-line injector. Samples were eluted with a mobile phase containing methanol-acetonitrile-100 mM monosodium phosphate (pH 5.0) (20:20:60, v/v). The UV wavelength was set at 254 nm for monitoring the analyte. Using the retrograde method, at infusion concentrations of 1 and 5 microg/ml of cephalothin, the in vivo microdialysis recoveries were 48.4+/-4.5% and 52.9+/-4.7% for the rat blood (n=6). Intra- and inter-assay accuracy and precision of the analyses were < or = 10% in the range of 0.01 through 10 microg/ml. Pharmacokinetic parameters were calculated from the recovery corrected dialysate concentrations of cephalothin versus time data. The results suggest that the pharmacokinetics of unbound cephalothin in blood fitted best to the two-compartmental model following cephalothin administration (50 mg/kg, i.v.).

Determination of ticarcillin epimers in plasma and urine with high-performance liquid chromatography

A high-performance liquid chromatogaphic method was developed for determining the concentrations of ticarcillin (TIPC) epimers in human plasma and urine. Samples were prepared for HPLC analysis with a solid-phase extraction method and the concentrations of TIPC epimers were determined using reversed-phase HPLC. The mobile phase was a mixture of 0.005 M phosphate buffer (pH 7.0) and methanol (12:1, v/v) with a flow-rate of 1.0 ml/min. TIPC epimers were detected at 254 nm. Baseline separation of the two epimers was observed for both plasma and urine samples with a detection limit of ca. 1 microg/ml with a S/N ratio of 3. No peaks interfering with either of the TIPC epimers were observed on the HPLC chromatograms for blank plasma and urine. The recovery was more than 80% for both plasma and urine samples. C.V. values for intra- and inter-day variabilities were 0.9-2.1 and 1.1-6.4%, respectively, at concentrations ranging between 5 and 200 microg/ml. The present method was used to determine the concentrations of TIPC epimers in plasma and urine following intravenous injection of TIPC to a human volunteer. It was found that both epimers were actively secreted into urine and that the secretion of TIPC was not stereoselective. Plasma protein binding was also measured, which revealed stereoselective binding of TIPC in human plasma.

Diastereomeric beta-lactam antibiotics. Analytical methods, isomerization and stereoselective pharmacokinetics

Stereospecific HPLC methods for the determination of various diastereomeric beta-lactam antibiotics are reviewed. Stereoselectivity in the absorption, distribution and excretion of several diastereomeric beta-lactams is summarized. The isomerization of beta-lactam isomers and its influence on the pharmacokinetics and pharmacodynamics are discussed.

Determination of ticarcillin in human plasma and in urine by reversed-phase LC

A liquid chromatographic assay for ticarcillin (ticar.) in plasma and urine is described. For analysis, the internal standard cefoperazone (cfp) is dissolved in acetonitrile, which is used for precipitating the protein. The supernatant is evaporated, reconstituted in running mobile phase and injected directly onto the reversed-phase C18 column, with detection at 205 nm. The mobile phase is composed of water-acetonitrile-o-phosphoric acid-tetramethylammonium chloride (TMA). Coefficients of variation for reproducibility were in the range of 2.2-15.5% for extra-low, low, medium and high controls. Limits of detection were 0.5 microgram ml-1 for plasma and 1 microgram ml-1 for urine. No interference from other cephalosporins or other antibiotics was noted. This liquid chromatographic assay is simple, accurate, requires no extraction and overcomes previous problems related to the drug's peak splitting due to isomerization.

Development and validation of an LC method for the quantitation of carbenicillin in human serum

An LC method for the quantitation of carbenicillin in human serum has been developed and validated. After protein precipitation with acetonitrile and evaporation, the residue was taken up by citric acid at pH 1.9. Carbenicillin and the internal standard (I.S.), piperacillin, were extracted with ethyl acetate, evaporated to dryness and reconstituted with a buffer solution. The separation of carbenicillin,, the I.S., and matrix peaks was achieved on a Microsorb C18, 3 microns column with a mobile phase of acetonitrile-tetrabutylammonium-phosphate buffer (pH* 6.6). The detection was by UV at 208 nm. The run time was 8 min. The established linearity range was 0.25-20 microgram ml-1 (r2 > 0.99) with a limit of quantitation of 0.25 microgram ml-1. Interday precision (RSD) and bias over the entire range were 1.1-6.9% and -1.83 to +2.80%, respectively. The interday precision (RSD) and bias for the QC samples at 0.75, 3.0 and 12 micrograms ml-1 were 5.9-7.9% and -2.80 to +2.30%, respectively. Stabilities of on-system, bench top, freeze-thaw cycles and sample storage were established.

Compatibility of cefazolin and gentamicin in peritoneal dialysis solutions

The compatibility of cefazolin and gentamicin in fluid commonly used for continuous ambulatory peritoneal dialysis (CAPD) was studied. Five admixtures containing cefazolin (75 mg/L and 150 mg/L) and gentamicin (8 mg/L), alone and in combination, were prepared in 1.5% dextrose peritoneal dialysis solution. Solutions were stored for 48 hours at 4 degrees C, 26 degrees C, and 37 degrees C; aliquots for drug assay were obtained at 0, 4, 8, 24, and 48 hours. HPLC and immunofluorescent assays were used to determine cefazolin and gentamicin concentrations, respectively. The cefazolin and gentamicin concentration changes over the study period did not reach statistical significance. Maximal cefazolin and gentamicin losses (12 and 7 percent of the initial concentrations, respectively) were observed at 48 hours in solutions stored at 37 degrees C. No significant differences in concentration changes were observed between combination solutions and solutions containing either cefazolin or gentamicin alone. Cefazolin and gentamicin, alone or in combination, are compatible for at least 48 hours in CAPD solutions.

Determination of ticarcillin levels in serum by high-pressure liquid chromatography

A high-pressure liquid chromatographic method for determining the concentrations of ticarcillin in serum was developed and compared, with 93 patient sera, to a standard agar well diffusion bioassay. For analysis, serum plus temocillin, the internal standard, were extracted with chloroform-n-amyl alcohol and back extracted into phosphate buffer. A reverse-phase C18 column and an ammonium acetate-methanol mobile phase were used with detection at 242 nm. Reproducibility studies yielded coefficients of variation ranging from 2.4 to 4.7% for low, mid, and high controls. Although cefoxitin, cephalothin, and cefuroxime exhibited retention similar to that of ticarcillin, a wide range of commonly administered antibiotics and other drugs did not interfere. The high-pressure liquid chromatographic assay is an accurate, reproducible method for determining the concentration of ticarcillin in serum during multiple antibiotic therapy or when rapid results are required.

Stability of metronidazole and ten antibiotics when mixed with magnesium sulphate solutions

The chemical stabilities of metronidazole (in water) and ten antibiotics (ampicillin, carbenicillin, cefamandole, cefazolin, cefoxitin, moxalactam, nafcillin, penicillin G, piperacillin, and ticarcillin) in 5% dextrose injection (except ampicillin which was in 0.9% sodium chloride) with magnesium sulphate were studied at 25 degrees C. The clarity of the solutions did not change in 20 h. The pH values of metronidazole, nafcillin and penicillin G solutions containing magnesium sulphate were lower (at 0 and 20 h) by up to 1.2 units as compared with solutions without magnesium sulphate. The decomposition of nafcillin and penicillin G solutions was hastened significantly by magnesium sulphate due to effect on the pH values of the solutions.

Epimerization kinetics of moxalactam, its derivatives, and carbenicillin in aqueous solution

The mechanism of the epimerization of moxalactam was studied by measuring the rate of epimerization after deuteration of the C-7 side-chain chiral carbon, introduction of different substituents on the side chain, and variation of the ring system. Deuteration slowed the epimerization rate considerably. The rate was also influenced by the choice of the ring system and the substituent on the C-7 side-chain chiral carbon. When the penicillin ring system with the 2-carboxy-2-phenyl-acetamide was studied, the epimerization rate decreased indicating that the same ring system needed to be used throughout the epimerization studies. Thus, experiments were conducted with different substituents replacing the phenolic group at the C-7 side-chain chiral carbon of moxalactam. The epimerization rate decreased in the substituent order thienyl, phenyl, 4-hydroxyphenyl, the ionized form of 4-hydroxyphenyl, and ethyl. These results showed that dehydrogenation of the chiral carbon seems to be the rate-determining step and that the stronger the electron-donating effect of the substituent, the slower the epimerization rate becomes.

Stability of cefotaxime sodium as determined by high-performance liquid chromatography

The stability of cefotaxime sodium in water (with either hydrochloric acid, phosphate buffers, or other ingredients) dextrose, and sodium chloride has been studied using a stability-indicating high-performance liquid chromatographic method with a relative standard deviation of 1.9% based on six injections. The optimum pH range of stability was determined to be approximately 4.3-6.2. In this pH range, the decomposition process was catalyzed only by the solvent. At pH less than or equal to 3.4, the hydrogen ion also catalyzed the reaction while at pH greater than 6.2, the hydroxyl ion hastened the process of decomposition. The solutions in 5% dextrose and 0.9% NaCl injections were stable for at least 1, 22, and 112 d at 24 degrees C, 4 degrees C, and -10 degrees C, respectively. For both solutions, the loss in potency was less than 5% at -10 degrees C in 224 d, less than 9% at 4 degrees C in 42 d, and less than 3.1% at 24 degrees C in 1 d.