Validation of HPLC and UV spectrophotometric methods for the determination of meropenem in pharmaceutical dosage form

Container closure integrity testing and process validation of closed system transfer devices for aseptic reconstitution of drug vials connected to fluid bags

OBJECTIVES

The closure integrity and process validation of closed system transfer devices (CSTDs) should be confirmed before implementation in clinical settings. We aimed to investigate the closure integrity and validate the aseptic procedure of two types of CSTDs by using a combination of the dye ingress test and a media fill test.

METHODS

The dye ingress test with methylene blue was used for both CSTDs with 10 samples of drug vials of three brands. A media fill test was performed with both CSTDs (300 samples per CSTD, 150 carried out in a safety cabinet and 150 under non-classified environmental conditions).

RESULTS

In all samples of both CSTDs, methylene blue was absent after visual inspection and spectrophotometric analysis. The nutrient media of one sample with CSTD A and none of the CSTD B samples were contaminated when reconstituted in a GMP grade A environment. Under non-classified environmental conditions, one sample of CSTD A and two samples of CSTD B were contaminated.

CONCLUSIONS

Both CSTDs connected to the drug vials met the terms of closure integrity by using the dye ingress test. The aseptic procedure of CSTD B was validated with the media fill test when reconstituted in a GMP grade A environment, but failed for CSTD A. Both CSTDs failed the media fill test when reconstituted under non-classified environmental conditions.

Quercetin nanoparticles decorated on Arabic gum and polyvinyl alcohol composite as a film sensor for fluorescence detection of meropenem

Moving towards green chemistry to minimize the diverse effect of chemicals on human health and environment has become a great issue in chemistry. On the other hand, determination of pharmaceuticals is an important issue for both human health and environment. In this regard two natural and benign compounds such as quercetin a polyphenolic flavonoid and Arabic Gum (AG) a polysaccharide were used to construct a sensor for meropenem. Herein, a new method was established for the synthesis of AG and polyvinyl alcohol (PVA) composite decorated by quercetin nanoparticles (QUENPs) as a fluorimetric film sensor to measure meropenem. In order to embed QUENPs in the polymer composite substrate, first QUENPs were synthesized and then added to the prepared composite solution under optimal conditions. The characteristics of AG and PVA composite (AG-PVA) and AG-PVA composite decorated by QUENPs films (QUENPs-AG-PVA), before and after the addition of meropenem was studied by TEM, FT-IR and EDX-Mapping. The developed film sensor was placed in a holder made with 3D printer. The difference in the fluorescence intensity of the fabricated film before and after the addition of meropenem was taken as the signal for measuring meropenem. The effect of different parameters on the fabrication of film fluorimetric sensor such as the concentration of polymer solutions, the volume of QUENPs and the volume of glycerol were investigated. Factors affecting the measurement of meropenem such as pH, type of buffer, volume of meropenem solution added on the sensor and time were also investigated. Under the obtained optimum conditions, the calibration graph was linear in the concentration range of 50-800 ng mL-1 with a correlation coefficient (r) of 0.9976 and the detection limit was 42.6 ng mL-1. The relative standard deviation was 3.5% and 1.4%, for eight replicate determinations of 100 ng mL-1 and 400 ng mL-1 of meropenem, respectively. The proposed method was successfully utilized for determination of meropenem in blood serum, human urine and pharmaceutical samples.

Spider chart, greenness and whiteness assessment of experimentally designed multivariate models for simultaneous determination of three drugs used as a combinatory antibiotic regimen in critical care units: Comparative study

In this study, five earth-friendly spectrophotometric methods using multivariate techniques were developed to analyze levofloxacin, linezolid, and meropenem, which are utilized in critical care units as combination therapies. These techniques were used to determine the mentioned medications in laboratory-prepared mixtures, pharmaceutical products and spiked human plasma that had not been separated before handling. These methods were named classical least squares (CLS), principal component regression (PCR), partial least squares (PLS), genetic algorithm partial least squares (GA-PLS), and artificial neural network (ANN). The methods used a five-level, three-factor experimental design to make different concentrations of the antibiotics mentioned (based on how much of them are found in the plasma of critical care patients and their linearity ranges). The approaches used for levofloxacin, linezolid, and meropenem were in the ranges of 3-15, 8-20, and 5-25 µg/mL, respectively. Several analytical tools were used to test the proposed methods' performance. These included the root mean square error of prediction, the root mean square error of cross-validation, percentage recoveries, standard deviations, and correlation coefficients. The outcome was highly satisfactory. The study found that the root mean square errors of prediction for levofloxacin were 0.090, 0.079, 0.065, 0.027, and 0.001 for the CLS, PCR, PLS, GA-PLS, and ANN models, respectively. The corresponding values for linezolid were 0.127, 0.122, 0.108, 0.05, and 0.114, respectively. For meropenem, the values were 0.230, 0.222, 0.179, 0.097, and 0.099 for the same models, respectively. These results indicate that the developed models were highly accurate and precise. This study compared the efficiency of artificial neural networks and classical chemometric models in enhancing spectral data selectivity for quickly identifying three antimicrobials. The results from these five models were subjected to statistical analysis and compared with each other and with the previously published ones. Finally, the whiteness of the methods was assessed by the recently published white analytical chemistry (WAC) RGB 12, and the greenness of the proposed methods was assessed using AGREE, GAPI, NEMI, Raynie and Driver, and eco-scale, which showed that the suggested approaches had the least negative environmental impact. Furthermore, to demonstrate solvent sustainability, a greenness index using a spider chart methodology was employed.

NOTICE OF DUPLICATE PUBLICATION: "Stability of meropenem in portable elastomeric infusion devices: which protocol should be implemented in clinical practice?"

The American Society for Microbiology (ASM) and Microbiology Spectrum are withdrawing the article mentioned below as it is an inadvertent duplicate publication: Esteban-Cartelle B, Serrano DR, Pérez Menéndez-Conde C, Vicente-Oliveros N, Álvarez-Díaz A, Abete JF, Martín-Dávila P. 2024. Stability of meropenem in portable elastomeric infusion devices: which protocol should be implemented in clinical practice? Microbiol Spectr 12:e02063-23. https://doi.org/10.1128/spectrum.02063-23. This article was accidentally published twice in the journal due to a technical error, and there are no ethical or integrity concerns regarding the original published article. The duplicate version of the article has been withdrawn to correct the scholarly record. The original published article and its content are not affected by this withdrawal and can be found here: https://journals.asm.org/doi/10.1128/spectrum.02064-23 The American Society for Microbiology apologizes to the authors and its readers for the technical error and the inconvenience this may have caused. The authors agreed with the publication of this notice.

Stability of meropenem in portable elastomeric infusion devices: which protocol should be implemented in clinical practice?

IMPORTANCE

Although outpatient parenteral antibiotic therapy can be a good approach to treating infections, a lack of data regarding antibiotic stability in portable elastomeric infusion devices restricts its safe and effective use. Actually, meropenem is used for prolonged periods above 24 h, and it is not physicochemically stable, which can compromise efficacy and toxicity. This work is of high importance to show the clinicians the real shelf life of meropenem when administered in portable elastomeric infusion devices. We propose several administration protocols for meropenem in portable elastomeric infusion devices in clinical practice, according to the stability drug results obtained in our study.

24/7 Therapeutic Drug Monitoring of Beta-Lactam Antibiotics with CLAM-2000

BACKGROUND

The aim of this study was to evaluate the CLAM-2000 automated preanalytical sample preparation module with integrated liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) as a method for 24/7 therapeutic drug monitoring (TDM) of beta-lactam antibiotics in routine clinical diagnostics.

METHODS

Method validation was performed using quality control samples. Method comparison was performed with routine samples from patients treated with beta-lactam antibiotics.

RESULTS

The determination of piperacillin, meropenem, ceftazidime, flucloxacillin, and cefotaxime was performed using D5-piperacillin and D6-meropenem as internal standards. The linearity of the method was within the therapeutic range of beta-lactam antibiotics. The imprecision and accuracy data obtained from quality control samples were within 15%, and the imprecision of patient samples on the instrument was less than the 5% coefficient of variation (CV). Internal standards stored in the instrument at 9 °C for at least one week were stable, which facilitated reagent use and storage.

CONCLUSION

The CLAM-2000 (Shimadzu, Kyoto, Japan) provides reproducible results as an established routine instrument and is a useful tool for 24/7 TDM of beta-lactam antibiotics in routine clinical diagnostics.

Meropenem PK/PD Variability and Renal Function: "We Go Together"

BACKGROUND

Meropenem is a carbapenem antibiotic widely employed for serious bacterial infections. Therapeutic drug monitoring (TDM) is a strategy to optimize dosing, especially in critically ill patients. This study aims to show how TDM influences the management of meropenem in a real-life setting, not limited to intensive care units.

METHODS

From December 2021 to February 2022, we retrospectively analyzed 195 meropenem serum concentrations (Css). We characterized patients according to meropenem exposure, focusing on the renal function impact.

RESULTS

A total of 36% (n = 51) of the overall observed patients (n = 144) were in the therapeutic range (8-16 mg/L), whereas 64% (n = 93) required a meropenem dose modification (37 patients (26%) underexposed; 53 (38%) overexposed). We found a strong relationship between renal function and meropenem concentrations (correlation coefficient = -0.7; p-value < 0.001). We observed different dose-normalized meropenem exposure (Css/D) among renal-impaired (severe and moderate), normal, and hyperfiltrating patients, with a median (interquartile range) of 13.1 (10.9-20.2), 7.9 (6.1-9.5), 3.8 (2.6-6.0), and 2.4 (1.6-2.7), respectively (p-value < 0.001).

CONCLUSIONS

Meropenem TDM in clinical practice allows modification of dosing in patients inadequately exposed to meropenem to maximize antibiotic efficacy and minimize the risk of antibiotic resistance, especially in renal alterations despite standard dose adaptations.

Therapeutic drug monitoring of carbapenem antibiotics in critically ill patients: an overview of principles, recommended dosing regimens, and clinical outcomes

INTRODUCTION

The importance of antibiotic treatment for sepsis in critically ill septic patients is well established. Consistently achieving the dose of antibiotics required to optimally kill bacteria, minimize the development of resistance, and avoid toxicity is challenging. The increasing understanding of the pharmacokinetic and pharmacodynamic (PK/PD) characteristics of antibiotics, and the effects of critical illness on key PK/PD parameters, is gradually re-shaping how antibiotics are dosed in critically ill patients.

AREAS COVERED

The PK/PD characteristics of commonly used carbapenem antibiotics, the principles of the application of therapeutic drug monitoring (TDM), and current as well as future methods of utilizing TDM to optimally devise dosing regimens will be reviewed. The limitations and evidence-base supporting the use of carbapenem TDM to improve outcomes in critically ill patients will be examined.

EXPERT OPINION

It is important to understand the principles of TDM in order to correctly inform dosing regimens. Although the concept of TDM is attractive, and the ability to utilize PK software to optimize dosing in the near future is expected to rapidly increase clinicians' ability to meet pre-defined PK/PD targets more accurately, current evidence provides only limited support for the use of TDM to guide carbapenem dosing in critically ill patients.

Development of a sustainable nanosensor using green Cu nanoparticles for simultaneous determination of antibiotics in drinking water

In this work, a novel, cost-effective, and eco-friendly electrochemical (EC) nanosensor was fabricated for the simultaneous detection of daptomycin (DAP) and meropenem (MEROP). EC methods have been developed for the determination of antibiotics. In this context, green synthesized copper nanoparticles (CuNPs) using Moringa oleifera plant extract were used as electrode modifiers. The incorporation of CuNPs was proposed to enhance the sensitivity and allow the simultaneous quantification of both antibiotics in water. Transmission electron microscopy (TEM), dynamic light scattering (DLS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, UV-visible spectroscopy, and field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDX) were employed to characterize CuNPs. Physical adsorption of 20.0 nm (±2.2 nm) spherical CuNPs on the surface of screen-printed carbon electrodes (SPCEs) induced a remarkable electrocatalytic effect. Indeed, the detection of both antibiotics exhibited a limit of detection (LOD) of 0.01 g L^-1. The response to various interfering species was assessed. Finally, the quantification of DAP and MEROP in drinking water was demonstrated, confirming the potential of the developed sensor for environmental monitoring applications.

Conceptual model of adding antibiotics to dialysate fluid during renal replacement therapy

Studies have shown significant variability in antibiotic trough concentrations in critically ill patients receiving renal replacement therapy (RRT). The purpose of this study was to assess whether adding beta-lactam antibiotics to dialysate solution can maintain stable antibiotic concentrations during RRT in experimental conditions. A single compartment model reflecting the patient was constructed and connected to the RRT machine. Dialysate fluid was prepared in three different concentrations of meropenem (0 mg/L; 16 mg/L; 64 mg/L). For each dialysate concentration various combinations of dialysate and blood flow rates were tested by taking different samples. Meropenem concentration in all samples was calculated using spectrophotometry method. Constructed experimental model results suggest that decrease in blood meropenem concentration can be up to 35.6%. Moreover, experimental data showed that antibiotic loss during RRT can be minimized and stable plasma antibiotic concentration can be achieved with the use of a 16 mg/L Meropenem dialysate solution. Furthermore, increasing meropenem concentration up to 64 mg/L is associated with an increase antibiotic concentration up to 18.7–78.8%. Administration of antibiotics to dialysate solutions may be an effective method of ensuring a constant concentration of antibiotics in the blood of critically ill patients receiving RRT.

Real-time TDM-based optimization of continuous-infusion meropenem for improving treatment outcome of febrile neutropenia in oncohaematological patients: results from a prospective, monocentric, interventional study

Objectives

To assess the role that real-time therapeutic drug monitoring (TDM)-guided optimization of continuous-infusion (CI) meropenem may have in maximizing empirical treatment and in preventing breakthrough infection and/or colonization with carbapenem-resistant Enterobacteriaceae (CRE) among oncohaematological patients with febrile neutropenia (FN).

Methods

A monocentric, interventional, prospective study was conducted. The pharmacodynamic (PD) target was a steady-state meropenem concentration-to-MIC ratio (C_ss/MIC) of 4–8. The primary endpoint was 14 day all-cause mortality. The secondary endpoint was the prevalence of CRE colonization in rectal swabs of patients rehospitalized within 3 months.

Results

Among the 75 patients enrolled, most (56%) had AML, almost half (37/75, 49.3%) underwent HSCT and one-third (32%) received meropenem as monotherapy. Meropenem dosages were adjusted in 30.1% of TDM reassessments. Gram-negative infections were microbiologically documented in 20.0% of patients. All of the 12 patients having infections caused by in vitro meropenem-susceptible pathogens attained the desired PD target and were cured. Three patients had infections caused by in vitro meropenem-resistant pathogens. Two of these achieved a C_ss/MIC target of 1 and were cured; the other one achieved a suboptimal PD target (0.59) and died. The 14 day all-cause mortality (10.7%) was significantly associated, at multivariate regression, with HSCT (OR 0.086, 95% CI 0.008–0.936, P = 0.044) and with augmented renal clearance (OR 10.846, 95% CI 1.534–76.672, P = 0.017). None of the patients who had hospital readmissions in the 3 month follow-up (63/75) had CRE colonization in rectal swabs.

Conclusions

Real-time TDM-guided CI meropenem may be a useful approach for attaining adequate exposure and preventing CRE emergence in FN oncohaematological patients.

Effectiveness of Pharmacokinetic/Pharmacodynamic-Guided Meropenem Treatment in Critically Ill Patients: A Comparative Cohort Study

BACKGROUND

The proper dosage of antibiotics is a key element in the effective treatment of infection, especially in critically ill patients. This study aimed to evaluate the efficacy of optimized meropenem regimens based on pharmacokinetic/pharmacodynamic criteria in patients admitted to the intensive care unit.

METHODS

This observational, naturalistic, retrospective, unicentric cohort study was performed between May 2011 and December 2017. The clinical and bacteriologic responses of 77 control intensive care unit patients receiving meropenem were compared with those of 77 propensity score-balanced patients who received meropenem dose adjusted by therapeutic drug monitoring. The primary end point of clinical response was a reduction at the end of treatment of at least 80% of the maximum procalcitonin (PCT) value recorded during the meropenem treatment.

RESULTS

The primary end point was met by 55 patients (71.4%) in the adjusted group compared with 41 (53.3%) patients in the control group (mean difference 18.1%, P = 0.02). Fifty-one patients (66.2%) in the adjusted group required a meropenem dose adjustment, being necessary in 46 of them (90.2%) to decrease the dose. The reduction of PCT was the greatest in the adjusted group compared with the unadjusted group (93% versus 85%, P = 0.004); a greater percentage of patients reached a PCT level < 0.5 ng/mL (63.6% versus 41.6%, P = 0.006), and there was a trend toward an improved bacteriologic response (relative risk = 1.27; 95% confidence interval: 0.92-1.56). There were no differences in early mortality or safety between groups.

CONCLUSIONS

Adjustment of meropenem therapy by monitoring is a useful strategy for improving meropenem effectiveness in the treatment of infection in critically ill patients, with no impact on safety.

PLGA encapsulated γ-cyclodextrin-meropenem inclusion complex formulation for oral delivery

Meropenem (MER) is one of the last resort antibiotics used to treat resistant bacterial infections. However, the clinical effectiveness of MER is hindered due to chemical instability in aqueous solution and gastric pH, and short plasma half-life. Herein, a novel multi-material delivery system based on γ-cyclodextrin (γ-CD) and poly lactic-co-glycolic acid (PLGA) is demonstrated to overcome these challenges. MER showed a saturated solubility of 14 mg/100 mL in liquid CO₂ and later it was loaded into γ-CD to form the inclusion complex using the liquid CO₂ method. The γ-CD and MER inclusion complex (MER-γ-CD) was encapsulated into PLGA by the well-established double emulsion solvent evaporation method. The formation of the inclusion complex was confirmed using FTIR, XRD, DSC, SEM, and ¹H NMR and docking study. Further, MER-γ-CD loaded PLGA nanoparticles (MER-γ-CD NPs) were characterized by SEM, DLS, and FTIR. The drug loading and entrapment efficiency for MER-γ-CD were 21.9 and 92. 2% w/w, respectively. However, drug loading and entrapment efficiency of MER-γ-CD NPs was significantly lower at up to 3.6 and 42.1% w/w, respectively. In vitro release study showed that 23.6 and 27.4% of active (non-degraded drug) and total drug (both degraded and non-degraded drug) were released from MER-γ-CD NPs in 8 h, respectively. The apparent permeability coefficient (Papp) (A to B) for MER, MER-γ-CD, and MER-γ-CD NPs were 2.63 × 10^-6 cm/s, 2.81 × 10^-6 cm/s, and 2.92 × 10^-6 cm/s_, respectively. For secretory transport, the Papp (B to A) were 1.47 × 10^-6 cm/s, 1.53 × 10^-6 cm/s, and 1.58 × 10^-6 cm/s for MER, MER-γ-CD and MER-γ-CD NPs_, respectively. Finally, the MER-γ-CD inclusion complex and MER-γ-CD NPs retained MER's antibacterial activities against Staphylococcus aureus and Pseudomonas aeruginosa. Overall, this work demonstrates the significance of MER-γ-CD NPs to protect MER from gastric pH with controlled drug release, while retaining MER's antibacterial activity.

Pinacho D. Personalized Medicine for Antibiotics: The Role of Nanobiosensors in Therapeutic Drug Monitoring

Due to the high bacterial resistance to antibiotics (AB), it has become necessary to adjust the dose aimed at personalized medicine by means of therapeutic drug monitoring (TDM). TDM is a fundamental tool for measuring the concentration of drugs that have a limited or highly toxic dose in different body fluids, such as blood, plasma, serum, and urine, among others. Using different techniques that allow for the pharmacokinetic (PK) and pharmacodynamic (PD) analysis of the drug, TDM can reduce the risks inherent in treatment. Among these techniques, nanotechnology focused on biosensors, which are relevant due to their versatility, sensitivity, specificity, and low cost. They provide results in real time, using an element for biological recognition coupled to a signal transducer. This review describes recent advances in the quantification of AB using biosensors with a focus on TDM as a fundamental aspect of personalized medicine.

Population Pharmacokinetics of Continuous-Infusion Meropenem in Febrile Neutropenic Patients with Hematologic Malignancies: Dosing Strategies for Optimizing Empirical Treatment against Enterobacterales and P. aeruginosa

A population pharmacokinetic analysis of continuous infusion (CI) meropenem was conducted in a prospective cohort of febrile neutropenic (FN) patients with hematologic malignancies. A non-parametric approach with Pmetrics was used for pharmacokinetic analysis and covariate evaluation. Monte Carlo simulations were performed for identifying the most appropriate dosages for empirical treatment against common Enterobacterales and P. aeruginosa. The probability of target attainment (PTA) of steady-state meropenem concentration (Css)-to-minimum inhibitory concentration (MIC) ratio (Css/MIC) ≥1 and ≥4 at the European Committee on Antimicrobial Susceptibility Testing (EUCAST) clinical breakpoint of 2 mg/L were calculated. Cumulative fraction of response (CFR) against Enterobacterales and P. aeruginosa were assessed as well. PTAs and CFRs ≥ 90% were considered optimal. A total of 61 patients with 178 meropenem Css were included. Creatinine clearance (CL_CR) was the only covariate associated with meropenem clearance. Monte Carlo simulations showed that dosages of meropenem ranging between 1 g q8h and 1.25 g q6h by CI may grant optimal PTAs of Css/MIC ≥4 at the EUCAST clinical breakpoint. Optimal CFRs may be granted with these dosages against the Enterobacterales at Css/MIC ≥ 4 and against P. aeruginosa at Css/MIC ≥ 1. When dealing against P. aeruginosa at Css/MIC ≥ 4, only a dosage of 1.5 g q6h by CI may grant quasi-optimal CFR (around 80–87%). In conclusion, our findings suggest that dosages of meropenem ranging between 1 g q8h and 1.25 g q6h by CI may maximize empirical treatment against Enterobacterales and P. aeruginosa among FN patients with hematologic malignancies having different degree of renal function.

Ultra-performance liquid chromatography-tandem mass spectrometric method for quantitation of the recently Food and Drug Administration approved combination of vaborbactam and meropenem in human plasma

A parenteral medical combination containing vaborbactam and meropenem is used mainly to treat complicated urinary tract infections. A novel ultra-performance liquid chromatography tandem mass spectrometric method was developed for the sensitive determination of both compounds in human plasma. Sample preparation was performed by precipitation technique. The chromatographic separation was accomplished using the Acquity C18-BEH column, 0.01 M ammonium formate: acetonitrile (47 : 53, v/v) as a mobile phase with a flow rate of 0.2 ml min-1. Analytes were monitored by applying multiple reaction monitoring. The bioanalytical validation criteria were conducted following the Food and Drug Administration recommendations. The method was linear within range 0.5 to 50 µg ml-1, for both drugs. The intra-day and inter-day precision, as coefficient variation (% CV) and the accuracy, as % bias did not exceed 15% for both drugs. The percentage recovery of targeted analytes was not less than 77%, calculated at three quality control levels. The proposed method showed a suitable lower level of quantification value of 0.50 µg ml-1 for both analytes, which is far lower than the expected C max, which permits the use of this method for pharmacokinetic studies. The proposed method proved to be useful for the evaluation of this combination in both human plasma and pharmaceutical formulation.

Thermosensitive in situ liposomal gels loaded with antimicrobial agent for oral care in critically ill patients

Aim: A novel thermosensitive in situ gel loaded with meropenem (MP) liposomes was designed to improve retention in the oral cavity as a prophylactic measure to prevent ventilator-acquired pneumonia in critically ill patients. Methodology & results: Meropenem liposomes were incorporated into poloxamer 407 gels and gamma irradiated. Mean size of liposome was 247 nm, polydispersity index < 0.3 and zeta potential >-25 mV; properties remained unaltered even post sterilization. Permeation study revealed that 75.26% and 34% of MPs were released from MP in situ gel and MP in situ liposomal gel, respectively. The relation between viscosity (cp) and shear rate (1/s) indicate that in situ gels exhibited non-Newtonian behavior at 37°C. The study using Pseudomonas aeruginosa confirmed the antimicrobial activity of meropenem. Conclusion: Prolonged in situ residence, because of rapid gelation process enables an easy administration of meropenem as liposomal suspension in critically ill patients.

Stability in clinical use and stress testing of meropenem antibiotic by direct infusion ESI-Q-TOF: Quantitative method and identification of degradation products

An ESI-MS/MS method through direct infusion was validated for quantitative analysis of meropenem powder for injection. The validation parameters were established in a rapid analysis of 30 s. Drug stability was studied through the submission to stress testing, resulting on four degradation products. Under hydrolytic conditions, in acid, neutral and alkaline media, the major degradation product was formed through the cleavage of the β-lactam ring. Oxidation of the drug using H₂O₂ (3%) showed the formation of two degradation products from a decarboxylation reaction and N-oxide formation. Under high humidity conditions, there was detected a dimer product. The stability of meropenem after reconstitution was studied in conditions that simulate its clinical use. In samples reconstituted and diluted in infusion fluids, an extensive degradation was observed. At room temperature meropenem maintained its content > 90% for up to 4 h when prepared in 5% glucose and for up to 12 h when prepared in 0.9% NaCl. Through ESI-MS/MS analyzes it was observed a degradation product formed by β-lactam ring cleavage, detected in all conditions studied. It was also identified a degradation product formed only in 5% glucose, generated by the hydrolysis of β-lactam followed by the attachment of a glucose molecule to the nitrogen of the pyrrolidine ring. In general, all the results obtained in the stability studies contribute to the knowledge about this antibiotic and future candidates of this class.

An investigation of the stability of meropenem in elastomeric infusion devices

Purpose

To evaluate the stability of meropenem trihydrate in elastomeric infusion devices at a range of selected concentrations (6, 12, 20 and 25 mg/mL) at ambient, refrigeration and freezing temperatures.

Methods

Meropenem Ranbaxy^® (meropenem trihydrate equivalent to anhydrous meropenem 1 g) vials for injection were reconstituted with 0.9% sodium chloride and adjusted to pH 6.5 using 1 M hydrochloric acid. Following preparation, solutions were stored for 7 days at either 6.7°C in elastomeric infusion devices or at −19°C in glass vials; samples of each concentration were removed from the infusion devices at specific time-points and stored for 24 hrs at 22.5°C. All solutions were assayed at specific time-points using high-performance liquid chromatography. Forced degradation in hydrochloric acid, sodium hydroxide and hydrogen peroxide was carried out at 40°C.

Results

The lowest concentration of meropenem (6 mg/mL) displayed the highest stability. It maintained >90% of its initial concentration for up to 144 hrs when stored at 6.7°C and 72 hrs following 24 hrs storage at 22.5°C, having been initially refrigerated for 48 hrs. Meropenem 20 mg/mL required immediate administration following preparation under ambient temperatures, whilst meropenem 25 mg/mL did not remain stable following 24 hrs storage at ambient temperatures. Frozen meropenem solutions displayed good stability in all concentrations but were physically unstable due to the formation of a precipitate.

Conclusion

At lower concentrations, meropenem showed suitable stability for storage and administration in elastomeric infusion devices, at refrigerated temperatures. To enhance the stability of lower concentration solutions when exposed to ambient temperatures by ambulatory patients, a more adept method of maintaining lower temperatures that reflect refrigerated conditions for elastomeric infusion devices should be devised.

A novel and sensitive chemosensor based on a KMnO4–rhodamine B–CdS quantum dot chemiluminescence system for meropenem detection

The reaction of a KMnO₄–Rh B–l-cysteine capped CdS QD system is described as a novel chemiluminescence (CL) reaction. Meropenem exhibits a quenching effect on KMnO₄–Rh B–l-cysteine capped CdS QDs.

Pharmacokinetics and pharmacodynamics of continuous-infusion meropenem in pediatric hematopoietic stem cell transplant patients

This study explored the pharmacokinetics and the pharmacodynamics of continuous-infusion meropenem in a population of pediatric hematopoietic stem cell transplant (HSCT) patients who underwent therapeutic drug monitoring. The relationship between meropenem clearance (CLM) and estimated creatinine clearance (CLCR) was assessed by nonlinear regression. A Monte Carlo simulation was performed to investigate the predictive performance of five dosing regimens (15 to 90 mg/kg of body weight/day) for the empirical treatment of severe Gram-negative-related infections in relation to four different categories of renal function. The optimal target was defined as a probability of target attainment (PTA) of ≥90% at steady-state concentration-to-MIC ratios (C SS/MIC) of ≥1 and ≥4 for MICs of up to 8 mg/liter. A total of 21 patients with 44 meropenem C SS were included. A good relationship between CLM and estimated CLCR was observed (r (2) = 0.733). Simulations showed that at an MIC of 2 mg/liter, the administration of continuous-infusion meropenem at doses of 15, 30, 45, and 60 mg/kg/day may achieve a PTA of ≥90% at a C SS/MIC ratio of ≥4 in the CLCR categories of 40 to <80, 80 to <120, 120 to <200, and 200 to <300 ml/min/1.73 m(2), respectively. At an MIC of 8 mg/liter, doses of up to 90 mg/kg/day by continuous infusion may achieve optimal PTA only in the CLCR categories of 40 to <80 and 80 to <120 ml/min/1.73 m(2). Continuous-infusion meropenem at dosages up to 90 mg/kg/day might be effective for optimal treatment of severe Gram-negative-related infections in pediatric HSCT patients, even when caused by carbapenem-resistant pathogens with an MIC of up to 8 mg/liter.

How do we use therapeutic drug monitoring to improve outcomes from severe infections in critically ill patients?

High mortality and morbidity rates associated with severe infections in the critically ill continue to be a significant issue for the healthcare system. In view of the diverse and unique pharmacokinetic profile of drugs in this patient population, there is increasing use of therapeutic drug monitoring (TDM) in attempt to optimize the exposure of antibiotics, improve clinical outcome and minimize the emergence of antibiotic resistance. Despite this, a beneficial clinical outcome for TDM of antibiotics has only been demonstrated for aminoglycosides in a general hospital patient population. Clinical outcome studies for other antibiotics remain elusive. Further, there is significant variability among institutions with respect to the practice of TDM including the selection of patients, sampling time for concentration monitoring, methodologies of antibiotic assay, selection of PK/PD targets as well as dose optimisation strategies. The aim of this paper is to review the available evidence relating to practices of antibiotic TDM, and describe how TDM can be applied to potentially improve outcomes from severe infections in the critically ill.

Determination of meropenem in bacterial media by LC-MS/MS

To support the development of a dynamic in vitro human pharmacokinetic/pharmacodynamic simulation model for biofilm-mediated infections and study stability of meropenem, an LC-MS/MS method for the determination of meropenem in Luria Bertani (LB) media was developed and validated in an API2000 LC-MS/MS system. A partial validation was also performed in M9 media. Sample aliquots of 100μL (or 25μL for M9 media) were mixed with the internal standard (IS) ceftazidime and filtered. The filtrate was directly injected onto a C8 column eluted with ammonium formate (10mM, pH 4) and acetonitrile (0.1% formic acid) in a gradient mode. ESI(+) and MRM with ion pair m/z 384→68 for meropenem and m/z 547→468 for the IS were used for quantification. The calibration curve concentration range was 50 to 25,000ng/mL. The recovery was over 98%. In LB media, significant signal suppression was observed throughout the time period of detection when compared with mobile phase solvents, but the matrix effect was compensated well with the IS. In M9 media, much less signal suppression was observed. The method is simple, fast, and reliable. Using the method, stability of meropenem in LB and M9 media were tested. No significant degradation was observed for at least 8h in both LB media (37°C) and M9 media (30°C), but more than 15% degradation was observed overnight (∼20h). The method was transferred to an API5000 LC-MS/MS system using meropenem-d6 as the IS.

Ultraviolet spectrophotometry (dual wavelength and chemometric) and high performance liquid chromatography for simultaneous estimation of meropenem and sulbactam sodium in pharmaceutical dosage form

UV spectrophotometric and high performance liquid chromatography (HPLC) methods were developed for simultaneous determination of meropenem (MERM) and sulbactam sodium (SB) in injection. UV spectrophotometric methods were developed using 0.1N sodium hydroxide as solvent. The Beer's plot for dual wavelength method was linear in the range of 4-24 μg mL(-1) and 2-12 μg mL(-1) for MERM and SB, respectively. The percent recoveries were found to be 98.52±1.23% for MERM and 101.45±1.1% for SB. Chemometrics assisted UV spectrophotometry was performed using Partial Least Square (PLS) analysis model and Principal Component Regression (PCR) analysis model. The % recoveries of the MERM were found to be 100.61±0.06% and 101.31±0.12% using PLS and PCR, respectively. The % recoveries of the SB were found to be 98.29±0.09% and 97.61±0.13% using PLS and PCR, respectively. Chromatography was performed on Hypersil BDS C18 column using methanol:acetonitrile:water (10:20:70 v/v/v) as mobile phase. The retention times of MERM and SB were found to be 2.9 min and 2.25 min, respectively. Developed HPLC method was found to be linear in the range of 50-250 μg mL(-1) and 25-125 μg mL(-1) for MERM and SB, respectively. The % recoveries were found to be 98.85±0.25% and 98.63±0.34% for MERM and SB, respectively. The developed analytical methods did not show any interference of the excipients when applied to pharmaceutical dosage form.

Dosing nomograms for attaining optimum concentrations of meropenem by continuous infusion in critically ill patients with severe gram-negative infections: a pharmacokinetics/pharmacodynamics-based approach

The worrisome increase in Gram-negative bacteria with borderline susceptibility to carbapenems and of carbapenemase-producing Enterobacteriaceae has significantly undermined their efficacy. Continuous infusion may be the best way to maximize the time-dependent activity of meropenem. The aim of this study was to create dosing nomograms in relation to different creatinine clearance (CL(Cr)) estimates for use in daily clinical practice to target the steady-state concentrations (C(ss)s) of meropenem during continuous infusion at 8 to 16 mg/liter (after the administration of an initial loading dose of 1 to 2 g over 30 min). The correlation between meropenem clearance (CL(m)) and CL(Cr) was retrospectively assessed in a cohort of critically ill patients (group 1, n = 67) to create a formula for dosage calculation to target C(ss). The performance of this formula was validated in a similar cohort (group 2, n = 56) by comparison of the observed and the predicted C(ss)s. A significant relationship between CL(m) and CL(Cr) was observed in group 1 (r = 0.72, P < 0.001). The application of the formula to meropenem dosing in group 2, infusion rate (g/24 h) = [0.078 × CL(Cr) (ml/min) + 2.85] × target C(ss) × (24/1,000), led to a significant correlation between the observed and the predicted C(ss)s (r = 0.92, P < 0.001). Dosing nomograms based on CL(Cr) were created to target the meropenem C(ss) at 8, 12, and 16 mg/liter in critically ill patients. These nomograms could be helpful in improving the treatment of severe Gram-negative infections with meropenem, especially in the presence of borderline susceptible pathogens or even of carbapenemase producers and/or of pathophysiological conditions which may enhance meropenem clearance.

The UV-derivative spectrophotometry for the determination of doripenem in the presence of its degradation products

A spectrophotometric method was developed for the quantitative determination of doripenem in pharmaceutical dosage form (DORIBAX) in the presence of its degradation products. The first-derivative with or without the substration technique, depending on formed products degradation was applied (lambda=324 nm). The method was linear in the range concentration (0.42-11.30)x10(-2)mg L(-1) (r=0.9981), the limits of detection and quantification were 7.60 and 45.0 microg L(-1), respectively. Recovery of doripenem ranged from 99.85 to 102.97% in pharmaceutical dosage form. This method had a good precision (RDS from 0.35 to 2.93%). The observed rate constants for doripenem degradation were comparable to those obtained in recommended HPLC method.