HILIC LC-MS/MS method for the quantification of cefepime, imipenem and meropenem

Electrostatic Repulsion Hydrophilic Interaction Liquid Chromatography (ERLIC) for the Quantitative Analysis of Polyamines

Highly polar low molecular weight organic molecules are still very challenging to analyze by liquid chromatography. Yet, with the steadily increasing application of metabolomics and similar approaches in chemical analysis, separating polar compounds might be even more important. However, almost all established liquid chromatography techniques (i.e., normal and reversed phase, hydrophilic interaction liquid chromatography (HILIC), ion chromatography) struggle with either carry-over, low sensitivity, or a lack of retention. For improving these shortcomings, electrostatic repulsion hydrophilic interaction chromatography (ERLIC) might be an alternative. By combining a HILIC mobile phase, that is highly organic with a low water content, and an ion exchange column, a distinct layer system develops. When the analyte's charge is of the same direction as the stationary phase, retention and elution are determined by two antagonistic forces: electrostatic repulsion and hydrophilicity. One prominent group of challenging polar analytes are the polyamines cadaverine, putrescine, spermidine, and spermine. Carrying charges from +2 to +4 at physiological pH, these compounds are essential cell constituents and found in all living organisms. However, they are still notoriously challenging to analyze via the established liquid chromatography methods. In the present work, an ERLIC tandem mass spectrometry method has been exemplarily developed, optimized, and validated for the quantitative determination of cadaverine, putrescine, spermidine, and spermine. This method enables symmetrical peak shapes and good separation of analytes with different charges while simultaneously selectively detecting the co-eluting diamines by MS/MS. Furthermore, high linearity (R > 0.998) and sensitivity (LODs ≤ 2 ng/mL) have been proven. Thus, ERLIC may be interesting for both targeted and untargeted analysis approaches of highly charged low molecular weight organic molecules.

A Liquid Chromatography-Tandem Mass Spectrometry Method for Simultaneously Determining Meropenem and Linezolid in Blood and Cerebrospinal Fluid

Antibiotic therapy requires appropriate dosage of drugs for effective treatment. Too low antibiotic concentrations may lead to treatment failure and the development of resistant pathogens, whereas overdosing may cause neurological side effects or hemolytic diseases. Meropenem and linezolid are used only in the treatment of serious infections or when other antibiotics are no longer effective as well as for treating central nervous system infections. It is difficult or sometimes even impossible to predict the relation between dosing of antibiotics and its cerebrospinal fluid (CSF) concentration; thus, a method of determining antibiotics not only in the blood but also in the CSF is needed. Analytical method validation is an integral part of good laboratory practice and ensures high accuracy of the results. We performed complete validation process according to the Food and Drug Administration and European Medicine Agency, covering the aspects precision, specificity, accuracy, recovery, limit of detection, limit of quantification, stability, carry-over, and matrix effects. Our liquid chromatography-tandem mass spectrometry method for the simultaneous measurement of meropenem and linezolid in different matrix meets all the acceptance criteria. The method was successfully applied to determine meropenem and linezolid concentrations in serum and CSF samples obtained from children treated with these antibiotics.

Quantification of meropenem in serum and cerebrospinal fluid in children with bacterial meningitis with augmented renal clearance by UPLC-MS/MS

Meropenem is an ultrabroad-spectrum antimicrobial agent that is often recommended for the treatment of bacterial meningitis (BM) in children. However, a subtherapeutic phenomenon occurred in BM children complicated with augmented renal clearance (ARC) at the recommended dose of meropenem. To support its pharmacokinetics, a sensitive, fast and robust ultra-liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to measure meropenem concentrations in serum and cerebrospinal fluid (CSF). The method involved protein precipitation, and samples were diluted with a large proportion of water to eliminate solvent effects. The separation of samples was performed on a Waters Acquity™ BEH C18 column (2.1 × 50 mm i.d., 1.7 μm) with a gradient profile. The mobile phases were formic acid-water (1:1000, v/v) and acetonitrile. The linear range was good, with a concentration range of 0.100-100 μg/mL for serum and 0.0400-20.0 μg/mL for CSF. The intra-day and inter-day precisions were less than 8.0%, and the intra-day and inter-day accuracies varied -6.6% from 6.5% for the both serum and CSF. The selectivity, carry-over, dilution integrity, matrix effect, recovery and stability were validated according to international guidelines. The developed UPLC-MS/MS method successfully determined the meropenem concentrations in the serum and CSF of children with BM complicated with ARC. The results indicated that under the recommended dosing regimen (40 mg/kg every 8 h), the time to reach the effective treatment target of 50%T > MIC was only approximately 3 h and lower CSF concentrations of meropenem were observed in children with BM with ARC.

Development and Validation of a Strong Cation Exchange Chromatographic Column Coupled with High-Performance Liquid Chromatography Method for Meropenem and Evaluation of Its Stability in Human Plasma: Application to the Therapeutic Drug Monitoring

Meropenem is a wide inter-individual variability in the pharmacokinetic, and standard dosing may not be adequate in critically ill patients. Therapeutic drug monitoring is a useful tool to optimize dosing. Meropenem is the amphoteric compound with an isoelectric point of 5.15. The secondary amino group of meropenem is positively charged when pH ≤ 5.4, thus we attempted to separate by strong cation exchange (SCX) column using acetonitrile/25-mM potassium dihydrogen phosphate (pH 3.0; 60:40) as mobile phase, and good peak shape and effective separation obtained. Generally, meropenem were unstable in plasma. We try to investigate stability of plasma samples using the medium QC sample with or without 3-(N-morpholino) propanesulfonic acid (MOPS) as stabilizer solutions at possible conditions during handling and storage. Meropenem showed higher stability at -80°C, and addition of MOPS might increase the short-term and extracted samples stability. This method is suitable for the quantification of meropenem in human plasma from 0.5 to 100 μg/mL. The accuracy was ranged from 96.53 to 101.11% with relative standard deviation ≤ 4.76%. The method has been used for determined 63 critically ill patients treated with meropenem. During the first measurement, 11 patients showed trough levels below the target ranges despite standard dosing. Through continuous or prolonged infusion, 8/11 patients (72.73%) led to adequate trough levels. The described SCX-high-performance liquid chromatography method for meropenem in human plasma is a powerful tool for therapeutic drug monitoring.

Effects of sewer biofilms on the degradability of carbapenems in wastewater using laboratory scale bioreactors

Carbapenems are last-resort antibiotics used to treat bacterial infections unsuccessfully treated by most common categories of antibiotics in humans. Most of their dosage is secreted unchanged as waste, thereby making its way into the urban water system. There are two major knowledge gaps addressed in this study to gain a better understanding of the effects of their residual concentrations on the environment and environmental microbiome: development of a UHPLC-MS/MS method of detection and quantification from raw domestic wastewater via direct injection and study of their stability in sewer environment during the transportation from domestic sewers to wastewater treatment plants. The UHPLC-MS/MS method was developed for four carbapenems: meropenem, doripenem, biapenem and ertapenem, and validation was performed in the range of 0.5-10 μg/L for all analytes, with limit of detection (LOD) and limit of quantification (LOQ) values ranging from 0.2-0.5 μg/L and 0.8-1.6 μg/L respectively. Laboratory scale rising main (RM) and gravity sewer (GS) bioreactors were employed to culture mature biofilms with real wastewater as the feed. Batch tests were conducted in RM and GS sewer bioreactors fed with carbapenem-spiked wastewater to evaluate the stability of carbapenems and compared against those in a control reactor (CTL) without sewer biofilms, over a duration of 12 h. Significantly higher degradation was observed for all carbapenems in RM and GS reactors (60 - 80%) as opposed to CTL reactor (5 - 15%), which indicates that sewer biofilms play a significant role in the degradation. First order kinetics model was applied to the concentration data along with Friedman's test and Dunn's multiple comparisons analysis to establish degradation patterns and differences in the degradation observed in sewer reactors. As per Friedman's test, there was a statistically significant difference in the degradation of carbapenems observed depending on the reactor type (p = 0.0017 - 0.0289). The results from Dunn's test indicate that the degradation in the CTL reactor was statistically different from that observed in either RM (p = 0.0033 - 0.1088) or GS (p = 0.0162 - 0.1088), with the latter two showing insignificant difference in the degradation rates observed (p = 0.2850 - 0.5930). The findings contribute to the understanding about the fate of carbapenems in urban wastewater and the potential application of wastewater-based epidemiology.

Determination of free and total meropenem levels in human plasma and its application for the consistency evaluation of generic drugs

RATIONALE

The consistency evaluation of generic drugs is important for the overall reformation of drug registration in China. In this study, we used meropenem as a model drug to explore the key techniques for clinical consistency evaluation by studying the plasma protein binding (PPB) ratio of different preparations. Because the free portion of drug is the effective part in vivo, it is essential to measure the free drug concentration in the circulatory system. Therefore, in this study, a fast and accurate high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method was developed to determine the total and free concentrations of meropenem in human plasma.

METHODS

Simple protein precipitation procedures were used for the sample processing assay, and ultrafiltration was implemented for the separation of free drugs. Liquid chromatography separation was performed using a hydrophilic interaction liquid chromatography (HILIC) silica column (2.1 × 50 mm, 3 μm). The mobile phase and sample preparation procedures were optimized. Factors affecting the measurement of free drug concentration were also determined. Nonspecific binding of the ultrafiltration membrane was negligible because the recovery rate for post-ultrafiltration was greater than 96%.

RESULTS

Under optimal conditions, the drug concentrations were linear from 0.5 to 50 μg/ml for both total and free drug concentrations. The PPB ratio was calculated based on the free and total drug concentrations. The PPB of meropenem varied from 1.4% to 24.2% in different subjects. The validated method was applied to evaluate PPB of four preparations, and the results varied from 6.57 ± 3.19% to 10.40 ± 8.31%. One-way analysis of variance (ANOVA) showed no significant differences between the four preparations.

CONCLUSIONS

We established a rapid, robust, and reliable method for the determination of total and free meropenem concentrations using LC-MS/MS with ultrafiltration techniques. The method provided a new perspective for the clinical consistency evaluation of generic drugs.

Preanalytical Stability of Flucloxacillin, Piperacillin, Tazobactam, Meropenem, Cefalexin, Cefazolin, and Ceftazidime in Therapeutic Drug Monitoring: A Structured Review

BACKGROUND

Therapeutic drug monitoring is increasingly being used to optimize beta-lactam antibiotic dosing. Because beta-lactams are inherently unstable, confirming preanalytical sample stability is critical for reporting reliable results. This review aimed to summarize the published literature on the preanalytical stability of selected widely prescribed beta-lactams used in therapeutic drug monitoring.

METHODS

The published literature (2010-2020) on the preanalytical stability of flucloxacillin, piperacillin, tazobactam, meropenem, cefalexin, cefazolin, and ceftazidime in human plasma, serum, and whole blood was reviewed. Articles examining preanalytical stability at room temperature, refrigerated, or frozen (-20°C) using liquid chromatography with mass spectrometry or ultraviolet detection were included.

RESULTS

Summarizing the available data allowed for general observations to be made, although data were conflicting in some cases (piperacillin, tazobactam, ceftazidime, and meropenem at room temperature, refrigerated, or -20°C) or limited (cefalexin, cefazolin, and flucloxacillin at -20°C). Overall, with the exception of the more stable cefazolin, preanalytical instability was observed after 6-12 hours at room temperature, 2-3 days when refrigerated, and 1-3 weeks when frozen at -20°C. In all cases, excellent stability was detected at -70°C. Studies focusing on preanalytical stability reported poorer stability than studies investigating stability as part of method validation.

CONCLUSIONS

Based on this review, as general guidance, clinical samples for beta-lactam analysis should be refrigerated and analyzed within 2 days or frozen at -20°C and analyzed within 1 week. For longer storage times, freezing at -70°C was required to ensure sample stability. This review highlights the importance of conducting well-designed preanalytical stability studies on beta-lactams and other potentially unstable drugs under clinically relevant conditions.

An Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry Method for Simultaneous Determination of 4 β-Lactam Antibiotics, Tazobactam, and Linezolid in Human Plasma Samples

BACKGROUND

Optimization of antimicrobial therapy is a challenge in critically ill patients who develop extreme interindividual and intraindividual pharmacokinetic variability. Therapeutic drug monitoring is a valuable tool for maximizing the effect of a drug and minimizing its adverse and unwanted effects. The aim of the current work was to develop and validate an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method to determine multiple antibiotics in clinical plasma samples from critically ill patients; low sample volume and rapid processing of samples were considered the main criteria.

METHODS

A separation method based on an online combination of UHPLC-MS/MS was developed for the simultaneous determination of 4 β-lactam antibiotics (cefepime, meropenem, cefotaxime, and piperacillin), tazobactam, and linezolid in human plasma samples. The volume of plasma sample used for analysis was 20 µL. The developed method was validated according to Food and Drug Administration guidelines.

RESULTS

The chromatographic run time was 8 minutes. Calibration curves were linear for concentration ranges of 0.1-100 mcg/mL (r 2 > 0.99) for tazobactam, meropenem, cefotaxime, linezolid, and piperacillin and 1-100 mcg/mL (r 2 > 0.99) for cefepime. The intraday and interday accuracy of the method ranged from 92.4% to 110.7% and 93.6% to 113.3%, respectively. The intraday and interday precision values were ≤17.3% and ≤17.4%, respectively. No interfering and carryover analytes were observed.

CONCLUSIONS

The developed UHPLC-MS/MS method is an appropriate and practical tool for therapeutic drug monitoring of the selected antibiotics. Owing to its rapidity, requirement of low sample volume, and high selectivity, sensitivity, and reliability, it can be effectively implemented in routine clinical laboratory tests for critically ill patients.

An LC-MS/MS method for the simultaneous determination of 18 antibacterial drugs in human plasma and its application in therapeutic drug monitoring

Antimicrobial resistance (AMR) is a major threat to global health due to the wide use of antibacterial drugs. Multiple studies show that the pharmacokinetic/pharmacodynamic (PK/PD) studies of antibiotics are an approach to prevent/delay AMR. The pharmacokinetic parameters of antibiotics are the basis of PK/PD studies, and therapeutic drug monitoring (TDM) is the key method to obtain pharmacokinetic information. We developed an ultra-performance liquid chromatography–tandem mass spectrometry to determine 18 antibacterial drugs (piperacillin, cefazolin, cefuroxime, cefoperazone, ceftriaxone, cefepime, aztreonam, meropenem, imipenem, levofloxacin, moxifloxacin, azithromycin, clindamycin, tigecycline, linezolid, vancomycin, voriconazole and caspofungin) in human plasma for practical clinical usage. Samples were prepared using protein precipitation with methanol. Chromatographic separation was accomplished in 6 min on a BEH C₁₈ column (2.1 × 100 mm, 1.7 µm) using a gradient elution of acetonitrile and 0.1% formic acid in water at a flow rate of 0.3 ml/min. The electrospray ionization source interface was operated in the positive and negative ionization modes. Inter- and intra-day precision, accuracy, recovery, matrix effect, and stability were validated according to the Food and Drug Administration guidance. The correlation coefficients of calibration curves were all greater than 0.99. The accuracies of the 18 antibacterial drugs ranged from 89.1% to 112.4%. The intra-day precision of the analytes ranged from 1.4% to 9.3% and the inter-day precision from 2.1% to 7.2%. The matrix effects ranged from 93.1% to 105.8% and the extraction recoveries ranged between 90.1% and 109.2%. The stabilities of the 18 antibacterial drugs in plasma were evaluated by analyzing three different concentrations following storage at three storage conditions. All samples displayed variations less than 15.0%. The validated method was successfully applied to routine clinical TDM for 231 samples.

Review on Characterization, Properties, and Analytical Methods of Cefepime

Infection is one of the most important reasons for the increase in the number of deaths worldwide; it can be a bacterial or viral infection. As a result, there are many effective drugs against this infection, especially bacterial ones. Cefepime (CP) is one of the fourth generations of cephalosporins and is distinguished from others in that it can kill both positive and negative bacteria. Therefore, this study focused on the chemical properties of the drug, its uses, and its stability against bacteria. All analysis methods for this drug in pharmaceutical preparations, blood, or plasma were also presented. One of the important problems in these methods is using toxic solvents, which poses a danger to society and the environment. The presentation of these solvents will allow companies to manufacture and use more effective and less toxic solvents.

Methods for Determination of Meropenem Concentration in Biological Samples

Measuring the concentration of antibiotics in biological samples allow implementation of therapeutic monitoring of these drugs and contribute to the adjustment of the dosing regimen in patients. This increases the effectiveness of antimicrobial therapy, reduces the toxicity of these drugs and prevents the development of bacterial resistance. This review article summarizes current knowledge on methods for determining concentration of meropenem, an antibiotic drug from the group of carbapenems, in different biological samples. It provides a brief discussion of the chemical structure, physicochemical and pharmacokinetic properties of meropenem, different sample preparation techniques, use of apparatus and equipment, knowledge of the advantages and limitations of available methods, as well as directions in which new methods should be developed. This review should facilitate clinical laboratories to select and apply one of the established methods for measuring of meropenem, as well as to provide them with the necessary knowledge to develop new methods for quantification of meropenem in biological samples according to their needs.

Dried Plasma Spot Based LC-MS/MS Method for Monitoring of Meropenem in the Blood of Treated Patients

Meropenem (MER) is widely used to treat complicated and serious infections. Therapeutic drug monitoring (TDM) provides a valid clinical tool to avoid suboptimal concentrations and dose−related adverse reactions. However, TDM seems to face challenges since the limited stability of MER in plasma makes transport difficult between clinics and laboratories. Dried plasma spot (DPS) sampling is an attractive but underutilized method for TDM that has the desired features of easy collection, storage, and transport, and overcomes known hematocrit (HCT) issues in dried blood spot (DBS) analysis. This study was designed to investigate a DPS−based liquid chromatography−tandem mass spectrometry (LC−MS/MS) method for quantification of MER. The method was developed and validated for DPS and wet plasma samples. Calibration curves were linear (R2 > 0.995) over the concentration range of 0.5−50 µg/mL. Overall accuracy and precision did not exceed 15% and no significant matrix effect was observed. MER has been more stable in DPS than in wet plasma samples. A comparison of DPS and wet plasma concentrations was assessed in 32 patients treated with MER. The results showed that there was no significant difference between the two methods. So the DPS method developed in this study is appropriate and practical for the monitor of MER in the daily clinical laboratory practice.

A sensitive and selective HPLC-MS3 method for therapeutic drug monitoring of meropenem and its validation by comparison with HPLC-MS2 methods

Meropenem, a representative β-lactam antibiotic, is widely used to treat complicated and serious infections. Therefore, it is a great significance to monitor the plasma drug concentration for individualized antimicrobial therapy. This study first describes the development and validation of high performance liquid chromatography-tandem mass spectrometry cubed method for monitoring meropenem in human plasma. Protein precipitation with methanol and a chromatographic analysis time of 7 min make this method is simple and high-throughput. Meropenem was extracted from human plasma with recoveries greater than 94.1%. Calibration curves were linear (R² >0.995) in the concentration range of 0.5-50 μg/mL. Overall accuracy and precision did not exceed 8.0% as well as no significant matrix effect was observed. The novelty of this method is that the triple-stage MS technology improves the selectivity and sensitivity. A comparison of the presented method and traditional liquid chromatography-tandem mass spectrometry method was assessed in 44 patients treated with meropenem and Passing-Bablok regression coefficients and Bland-Altman plots showed that no significant difference between the two methods. So the triple-stage MS method developed in this study is appropriate and practical for the monitor of meropenem in the daily clinical laboratory practice. This article is protected by copyright. All rights reserved.

Quantification of Antibiotics in Patient Samples: State of the Art in Standardization and Proficiency Testing

BACKGROUND

For many antibiotics, the convenient one-fits-all dosing regimen had to be abandoned. Owing to highly variable pharmacokinetics, therapeutic drug monitoring has become an indispensable prerequisite. It is based on a suitable measuring method, sample materials, and standardization. Appropriate quality control including external quality assessment (EQA) is essential. For many antibiotics, EQAs have been established for many decades, whereas others have only lately been introduced. This article gives an insight into the state of the art regarding the therapeutic drug monitoring of antibiotics regarding standardization, EQAs, and reference measurement procedures (RMPs).

METHODS

An overview of the currently available international EQA schemes for antibiotics and a literature overview of available RMPs are given. EQAs including gentamicin and vancomycin have been offered by German providers for more than 25 years. The period 2000-2020 was selected for a detailed analysis. The experiences with a new EQA including linezolid, meropenem, and piperacillin are described.

RESULTS

EQAs for gentamicin and vancomycin are provided in many countries. Those for linezolid, meropenem, and piperacillin do not seem to be very common. Most of the antibiotics monitored for decades are measured by commercially available assays. EQAs for linezolid, meropenem, and piperacillin introduced in 2018 were rapidly accepted in Germany. Methods reported in this study were HPLC based either with UV or mass spectrometric detection. The number of participants succeeding was comparable between UV and mass spectrometry. Candidate RMPs for gentamicin, vancomycin, and linezolid based on isotope dilution mass spectrometry were published.

CONCLUSIONS

EQAs are offered regularly for many antibiotics worldwide. The results of EQAs in Germany generally compare well, but there is potential for improvement. Both immunoassays and HPLC-based methods work properly in EQAs evaluated in Germany. From a quality control perspective, fast and inexpensive methods may be selected without endangering the patient's health based on clinical needs.

A fast and high-sensitivity liquid chromatography-tandem mass spectrometry method combined with in vivo microdialysis for quantification of meropenem in rabbits with sepsis under the simultaneous infusion of total parenteral nutrition: Application to a pharmacokinetic study

A fast and high-sensitivity liquid chromatography-tandem mass spectrometry (LC-MS/MS) method assisted by microdialysis was established for the determination of meropenem in total parenteral nutrition (TPN) infused plasma. A 10-times dilution was arranged for sample preparation to overcome the severe matrix effect caused by the high salt content in dialysate and complex composition of TPN. This quantification method was proved to be satisfied in selectivity, accuracy, precision, linearity (R²  > 0.998), recovery, matrix effect and stability. In the optimized conditions, the calibration curve range was set from 2 to 2000 ng/ml. This validated method was applied to pharmacokinetics study of meropenem in rabbits with sepsis (induced by cecal ligation and punctures) under simultaneous infusion of TPN to simulate the clinical practice. The results demonstrated that the LC-MS/MS method assisted by microdialysis can be used successfully for the determination of meropenem in TPN-infused plasma. Moreover, the area under the curve and the maximum concentrations in the plasma of meropenem in control rabbits were significantly smaller (P < 0.05), while clearance and distribution volumes were significantly greater (P < 0.05) than in those with sepsis. It could be speculated that drug monitoring in patients with sepsis may be necessary.

An isotope-dilution LC-MS/MS method for the simultaneous quantification of meropenem and its open-ring metabolite in serum

BACKGROUND

Therapeutic drug monitoring (TDM) of beta-lactam antibiotics and, among them, especially meropenem gains importance in the field of laboratory medicine. Meropenem is known to be unstable, resulting in a degradation product with an open beta-lactam ring. For a more comprehensive TDM of meropenem, the aim was to develop a LC-MS/MS method for the simultaneous quantification of meropenem and its main degradation product, the open-ring metabolite (ORM).

METHODS

The method involves a protein precipitation followed by chromatographic separation using a formic acid-ammonium formate methanol gradient on a pentafluorophenyl column. Multiple reaction monitoring in the positive ion mode and stable isotope labeled internal standards were used for quantification. Validation was performed according to the European Medicines Agency guideline.

RESULTS

Validation was successful performed within the linear drug concentration range of 1.0-100.0 mg/l for meropenem and 0.62-62.30 mg/l for the ORM. Investigation of selectivity, accuracy and precision showed good results and potential matrix effects were successfully compensated by the internal standards. The suitability of the method was shown by the comparison of 35 anonymized leftover serum samples from intensive care patients with routine analyses.

CONCLUSION

For the first time, we herein describe a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of meropenem and its ORM in human serum. The ratio of active to inactive compound provides valuable pharmaceutical and pharmacokinetic information, which may contribute to therapeutic efficacy.

Gold-Deposited Nickel Foam as Recyclable Plasmonic Sensor for Therapeutic Drug Monitoring in Blood by Surface-Enhanced Raman Spectroscopy

A sensitive and recyclable plasmonic nickel foam sensor has been developed for surface-enhanced Raman spectroscopy (SERS). A simple electrochemical method was used to deposit flower-shaped gold nanostructures onto nickel foam substrate. The high packing of the gold nanoflowers onto the nickel foam led to a high enhancement factor (EF) of 1.6 × 10¹¹. The new SERS sensor was utilized for the direct determination of the broad-spectrum β-lactam carbapenem antibiotic meropenem in human blood plasma down to one pM. The sensor was also used in High Performance Liquid Chromatography (HPLC)-SERS assembly to provide fingerprint identification of meropenem in human blood plasma. Moreover, the SERS measurements were reproducible in aqueous solution and human blood plasma (RSD = 5.5%) and (RSD = 2.86%), respectively at 200 µg/mL (n = 3), and successfully recycled using a simple method, and hence, used for the repeated determination of the drug by SERS. Therefore, the new sensor has a strong potential to be applied for the therapeutic drug monitoring of meropenem at points of care and intensive care units.