Stability and compatibility of reconstituted ertapenem with commonly used i.v. infusion and coinfusion solutions

Systematic review of room temperature stability of key beta-lactam antibiotics for extended infusions in inpatient settings

BACKGROUND

Extended infusion (EI) of beta-lactam antibiotics may offer clinical benefits aligned with improved probability of target attainment for critical pharmacokinetic/pharmacodynamic parameters that correlate with efficacy. There is much research interest in prolonged and continuous infusions (collectively, extended infusions) of beta-lactams to improve patient outcomes, particularly in critically ill patients in intensive care. While definitive clinical trial data demonstrating beneficial outcomes is awaited, there has been limited focus on the stability of the agents given by EI, which may be an equally critical parameter. EI may allow for savings in nursing time due to reduced need for drug reconstitution. We set out to examine the data for stability for EI at room temperature, consistent with the requirements of 'A Standard Protocol for Deriving and Assessment of Stability- Part 1 Aseptic Preparation (Small Molecules)', which allows a 5% loss of active pharmaceutical ingredient (API) applicable for those territories that use the British Pharmacopoeia also for a 10% loss applicable in much of rest of the world.

METHODS

Searches using preferred reporting items for systematic reviews and meta-analyses (PRISMA) principles for stability data on freshly prepared beta-lactam antimicrobials for extended administration at room temperature (at or above 23°C) were conducted in November 2021 and updated in December 2022.

RESULTS

We found data to support the extension of the shelf life of 12 key beta-lactam antibiotics once reconstituted (aztreonam, amoxicillin, benzylpenicillin, flucloxacillin, piperacillin/tazobactam, cefazolin, cefmetazole, ceftaroline, ceftazidime, ceftriaxone, imipenem and meropenem) compliant with the NHS protocol, and data for five other agents (ticarcillin, cefepime, cefiderocol, cefoxitin and doripenem) which would be acceptable in regions outside the UK beyond that listed in the Summary of Product Characteristics.This review has not been registered under PROSPERO.

Systematic review of stability data pertaining to selected antibiotics used for extended infusions in outpatient parenteral antimicrobial therapy (OPAT) at standard room temperature and in warmer climates

Aim

To determine if there are sufficient stability data to confirm appropriate prescribing of antibiotics commonly used in outpatient parenteral antimicrobial therapy (OPAT) in warmer climates.

Data sources

Four databases were systematically searched using the terms 'beta-lactams', or 'antibiotics', or 'anti-bacterial agents' and 'drug stability' or drug storage' for studies specific to drug stability published between 1966 and February 2018.

Study selection

The search strategy initially identified 2879 potential articles. After title and abstract review, the full-texts of 137 potential articles were assessed, with 46 articles matching the inclusion and exclusion criteria included in this review.

Results

A large volume of stability data is available for the selected drugs. Stability data at temperatures higher than 25°C were available for several of the medications, however few drugs demonstrated stability in warmer climates of 34°C or higher. Only buffered benzylpenicillin, cefoxitin and buffered flucloxacillin were found to have stability data supporting OPAT in warmer climates. Sequential data, profiling the drug for an extended period in solution under refrigeration prior to the run-out period at the higher temperatures, are also lacking.

Limitations

This study was limited by including only peer reviewed articles. There may be further grey literature supporting the stability of some of the drugs mentioned.

Conclusion

There are insufficient stability data of antibiotic use in warmer climates. Studies to verify the stability and appropriate use of many antibiotics used in OPAT at standard room temperature and in warmer climates are urgently required. Several drugs in current use in the OPAT settings are lacking stability data.

Implications

Further research in this field is needed to develop structured evidence-based guidelines. Results of this review should be further compared with observed patient outcomes in current clinical practice.

Newer antibiotics for the treatment of peritoneal dialysis-related peritonitis

Peritonitis is a debilitating infectious complication of peritoneal dialysis (PD). Drug-resistant bacterial peritonitis typically has a lower response rate to antibiotics. In the past 15 years, newer antibiotics with activities against drug-resistant Gram-positive bacteria have been developed. In most circumstances, peritonitis due to methicillin-resistant staphylococci responds to vancomycin. If vancomycin cannot be used due to allergy and/or non-susceptibility, there is increasing evidence that linezolid and daptomycin are the drugs of choice. It is reasonable to start linezolid orally or intravenously, but subsequent dose reduction may be necessary in case of myelosuppression. Daptomycin can be given intravenously or intraperitoneally and has excellent anti-biofilm activity. Other treatment options for drug-resistant Gram-positive bacterial peritonitis include teicoplanin, tigecycline and quinupristin/dalfopristin. Teicoplanin is not available in some countries (e.g. the USA). Tigecycline can only be given intravenously. Quinupristin/dalfopristin is ineffective against Enterococcus faecalis and there is only low-quality evidence to support its efficacy in the treatment of peritonitis. Effective newer antibiotics against drug-resistant Gram-negative bacteria are lacking. Polymyxins can be considered, but evidence on its efficacy is limited. In this review, we will discuss the potential use of newer antibiotics in the treatment of drug-resistant bacterial peritonitis in PD patients.

Stability of ertapenem 100 mg/mL in polypropylene syringes stored at 25, 4, and -20 °C

PURPOSE

The stability of ertapenem solution in syringes at room, refrigerator, and freezer temperatures was determined to establish options for extended storage.

METHODS

Six replicate solutions of ertapenem (100 mg/mL) in 0.9% sodium chloride injection were prepared in 20-mL polypropylene syringes and stored at 25, 4, or -20 °C. Syringe samples were collected immediately after preparation and at preselected time points and assayed by a validated high-performance liquid chromatography (HPLC) method. The ertapenem solution was considered stable if at least 90% of the mean initial concentration remained at the time of HPLC analysis.

RESULTS

The mean±S.D. baseline ertapenem concentration across all stability studies was 109.9±9.2 mg/mL. One hour after preparation, the mean±S.D. ertapenem concentration of samples kept at room temperature was 87.8±4.6% of the initial concentration. After 24 and 48 hours of refrigeration, mean±S.D. drug concentrations had declined to 93.6±5.9% and 86.2±4.3% of the respective baseline concentrations. Frozen syringes required 1 hour to thaw at room temperature; after 14 and 28 days of frozen storage, the mean±S.D. ertapenem concentrations of these samples 4 hours after thawing were 93.4±3.5% and 86.4±2.6% of the respective baseline values.

CONCLUSION

Ertapenem 100 mg/mL prepared in 20-mL polypropylene syringes was stable at room temperature for approximately 30 minutes. Room-temperature stability was extended to 4 hours after 24 hours of refrigeration. After being frozen for 14 or 28 days, ertapenem was stable for 3-5 hours after removal from the freezer.

Stability of Ertapenem 100 mg/mL in Manufacturer's Glass Vials or Syringes at 4°C and 23°C

BACKGROUND

Prophylactic administration of ertapenem as a single 1-g IV dose has been shown to reduce sepsis after prostate biopsy.

OBJECTIVE

To evaluate the stability of ertapenem after reconstitution with 0.9% sodium chloride to a final concentration of 100 mg/mL and storage in the manufacturer's original glass vials or polypropylene syringes.

METHODS

On study day 0, 100 mg/mL solutions of ertapenem were retained in the manufacturer's glass vials or packaged in polypropylene syringes and stored at 4°C or 23°C without protection from fluorescent room light. Samples were assayed periodically over 18 days using a validated, stability-indicating liquid chromatographic method with ultra-violet detection. A beyond-use date was determined as the time for the concentration to decline to 90% of the initial (day 0) concentration, based on the fastest degradation rate, with 95% confidence.

RESULTS

Reconstituted solutions stored in the manufacturer's glass vials or polypropylene syringes exhibited a first-order degradation rate, such that 10% of the initial concentration was lost in the first 2.5 days when stored at 4°C or within the first 6.75 h when stored at room temperature (23°C). Analysis of variance showed differences in the percentage remaining due to temperature (p < 0.001) and study day (p < 0.001) but not type of container (p = 0.98). When a 95% CI for the degradation rate was calculated and used to determine a beyond-use date, it was established that more than 90% of the initial concentration would remain for 2.35 days at 4°C and for 0.23 day (about 5 h, 30 min) at room temperature.

CONCLUSIONS

A 100 mg/mL ertapenem solution stored in the manufacturer's glass vial or a polypropylene syringe will retain more than 90.5% of the initial concentration when stored for 48 h at 4°C and for an additional 1 h at 23°C.

Good practice recommendations for paediatric outpatient parenteral antibiotic therapy (p-OPAT) in the UK: a consensus statement

There is compelling evidence to support the rationale for managing children on intravenous antimicrobial therapy at home whenever possible, including parent and patient satisfaction, psychological well-being, return to school/employment, reductions in healthcare-associated infection and cost savings. As a joint collaboration between the BSAC and the British Paediatric Allergy, Immunity and Infection Group, we have developed good practice recommendations to highlight good clinical practice and governance within paediatric outpatient parenteral antibiotic therapy (p-OPAT) services across the UK. These guidelines provide a practical approach for safely delivering a p-OPAT service in both secondary care and tertiary care settings, in terms of the roles and responsibilities of members of the p-OPAT team, the structure required to deliver the service, identifying patients and pathologies that are suitable for p-OPAT, ensuring appropriate vascular access, antimicrobial choice and delivery and the clinical governance aspects of delivering a p-OPAT service. The process of writing a business case to support the introduction of a p-OPAT service is also addressed.

Selective determination of ertapenem in the presence of its degradation product

Stability-indicative determination of ertapenem (ERTM) in the presence of its beta-lactam open-ring degradation product, which is also the metabolite, is investigated. The degradation product has been isolated, via acid-degradation, characterized and elucidated. Selective quantification of ERTM, singly in bulk form, pharmaceutical formulations and/or in the presence of its major degradant is demonstrated. The indication of stability has been undertaken under conditions likely to be expected at normal storage conditions. Among the spectrophotometric methods adopted for quantification are first derivative ((1)D), first derivative of ratio spectra ((1)DD) and bivariate analysis.

Stability of doripenem in vitro in representative infusion solutions and infusion bags

BACKGROUND

Doripenem, a new parenteral carbapenem with broad-spectrum antibacterial activity, is indicated for the treatment of complicated intra-abdominal infections and complicated urinary tract infections, including pyelonephritis. According to the US prescribing information, the carbapenems imipenem and meropenem are stable in sodium chloride for 4 hours.

OBJECTIVE

The aim of this study was to assess the stability of doripenem following constitution (50 mg/mL) and in injection solutions in vitro (0.9% sodium chloride and 5% dextrose) at a concentration of 5 mg/mL in room and refrigerated conditions.

METHODS

The stability of doripenem was assessed (1) under room-temperature conditions (25 degrees C +/- 2 degrees C, 60% +/- 5% relative humidity, under fluorescent light) immediately after constitution in vials with sterile water; (2) under room conditions and refrigerated conditions (5 degrees C +/- 3 degrees C, 60% relative humidity, protected from light) immediately after constitution with sodium chloride or dextrose in 3 different infusion bags (polyvinyl chloride [PVC], PVC with vial adapter, and polyethylene); and (3) under room and refrigerated conditions using 500-mg doripenem vials that had been stored for 12 months in room temperature and protected from light before constitution with water and dilution in sodium chloride or dextrose injection. Doripenem 5 mg/mL and related substances (degradation products and impurities related to doripenem) were measured using a validated high-performance liquid chromatography method. Doripenem was considered stable if its concentration remained within 90% to 110% of the initial concentration and the total concentration of degradation products and impurities related to doripenem was < or = 5%. Appearance of the solutions was assessed using clarity and comparison to color standards; pH, using standard methodologies; and particulate matter, using light-obscuration and microscopy.

RESULTS

Three lots of doripenem were assessed. Doripenem potency in constituted suspension (50 mg/mL) remained unchanged (means, 99.2% and 99.3%, respectively, of initial doripenem amount) for up to 60 minutes in room or refrigerated conditions prior to transfer to infusion bags. The doripenem 5-mg/mL infusion solution retained its potency for 12 and 72 hours under room and refrigerated conditions, respectively, in 0.9% sodium chloride injection, and for 4 and 48 hours under room and refrigerated conditions, respectively, in 5% dextrose injection (mean percentages of initial doripenem concentration, 95.5% and 96.6% under room and refrigerated conditions, respectively). Comparable results were obtained with vials of doripenem that had been stored for 12 months at room temperature and protected from light and then constituted (50 mg/mL). Doripenem 5 mg/mL in 0.9% sodium chloride injection or 5% dextrose injection retained its potency in room conditions at the end of a 4-hour drip period when used with conventional infusion sets (mean, 96.6%) or Di(2-ethylhexyl)phthalate-free infusion sets (mean, 99.3%).

CONCLUSIONS

Doripenem 5 mg/mL was stable for up to 12 hours in vitro in 0.9% sodium chloride at room temperature. Therefore, doripenem can be constituted, mixed with infusion fluids in the pharmacy, stored, delivered, and infused into a patient within a time frame suitable for 4-hour extended infusions.

A comparison of the stability of ertapenem and meropenem in pharmaceutical preparations in solid state

The following first-order rate constants of the degradation of ertapenem in INVANZ and meropenem in MERONEM were determined: (a) in dry air at 363, 373, 378, 383, 388, 393 K; (b) at increased relative air humidity (76.4% RH) at 313, 323, 333 and 343 K; (c) at increased relative air humidity (50.9, 60.5, 66.5, 76.4% RH-ertapenem and 50.9, 66.5, 76.4 and 90.0% RH-meropenem) at 333 K. The dependence ln k(i) = f(RH%) was described by the equations: ln k(i) = (6.63+/-1.22) x 10(-2) x (RH%)-13.36 +/- 1.68 (ertapenem) and ln k(i) = (4.22 +/- 2.98) x 10(-2) x (RH%)-12.14 +/- 2.16 (meropenem). The dependence lnk(i)=f(1/T) was described by equations: ln k(i) =19.4 +/- 2.6-(9230 +/- 800)(1/T) for ertapenem, at 76.4% RH; ln k(i) = 11.5 +/- 4.9-(9880 +/- 1800)(1/T) for ertapenem in dry air; ln k(i) = 14.8 +/- 11.9-(7785 +/- 3905)(1/T) for meropenem, at 76.4% RH; ln k(i) = 37.6 +/- 7.73-(18385 +/- 2930)(1/T) for meropenem in dry air. The thermodynamic parameters E(a), DeltaH( not equal) and DeltaS( not equal) of the degradation of ertapenem and meropenem were calculated. The difference between the influence of temperature on the stability of ertapenem and meropenem was not significant at 76.4% RH. In dry air (363-393 K) this influence was greater in the case of meropenem. The degradation of ertapenem was slower in this temperature range. Humidity was a significant factor affecting the degradation of these antibiotics and it influenced their stability is similar ways.

Kinetics of amoxicillin and clavulanate degradation alone and in combination in aqueous solution under frozen conditions

Kinetics of the reactions of amoxicillin sodium and potassium clavulanate alone and in combination were investigated in the frozen state at selected pH values of 2.0, 4.6 and 7.0. Extrapolation of the rate constant values to the frozen state from the liquid state data indicated marked acceleration of the rates of amoxicillin and clavulanate degradation for the pH values investigated. The highest acceleration in rate recorded was 15.0-fold for clavulanate and the lowest value was 4.6-fold for amoxicillin at -7.3 degrees C in the hydrochloric acid system. The rate constant values obtained were interpreted in terms of the concentration model [Pincock, R.E., Kiovsky, T.E., 1966. Kinetics of reactions in frozen solution. J. Chem. Educ. 43, 358-360], phase-temperature relationship of the solutes, buffer catalysis, pH change and polymerization reactions. A kinetic model was deduced for the hydrochloric acid system providing adequate explanation of the experimental results. A large stabilizing effect of sodium chloride used for maintaining constant ionic strength (micro=0.5) was evident in this system. The shelf-life of amoxicillin was increased from 2.2 to 58.7h at -7.3 degrees C when sodium chloride was included in the hydrochloric acid system.

Ertapenem: the new carbapenem 5 years after first FDA licensing for clinical practice

Ertapenem, a parenteral broad-spectrum 1-beta-methyl-carbapenem, was licensed 5 years ago for clinical practice in the US and Europe. The substance has a good in vitro activity against many common aerobic and anaerobic Gram-positive and -negative bacteria. Its in vitro activity against Enterobacteriaceae carrying plasmid- or chromosomal-mediated beta-lactamases, including AmpC- and extended-spectrum beta-lactamases, is especially clinically significant. Advantages concerning in vitro activity and low potential for so-called 'collateral damage', and development of own resistance during therapy, as shown in several randomized, controlled clinical trials, make ertapenem an excellent treatment choice for complicated aerobic and anaerobic mix infections caused by ertapenem-sensitive bacteria. On the other hand, due to its limited activity against Acinetobacter spp., enterococci and Pseudomonas aeruginosa, it is less suitable for late-onset nosocomial infections. International guidelines recommend the initial empirical use of ertapenem for intra-abdominal infections, skin and skin-structure infections, acute pelvic infections, complicated urinary tract infections and pneumonia (both community-acquired and 'early-onset' nosocomial) in a dose of 1.0 g administered once daily. However, recent results from pharmacokinetic/pharmacodynamic modelling studies in critically ill patients with ventilator-associated pneumonia and adipose volunteers with a body mass index of > or = 20 kg/m(2) showed that the standard dose of 1.0 g/day may not provide adequate free, protein-unbound drug concentrations in plasma and organ tissues. Therefore, a shortening of the dosage interval or continuous infusion of ertapenem should be considered to ensure optimal free concentrations in these particular populations.

Stability of ertapenem in aqueous solutions

The kinetics of degradation of ertapenem was studied in aqueous solutions at 303, 313, 323 and 333 K and pH 0.42-12.5. Degradation was studied using two methods: HPLC (LiChrospher RP-18 column, 5 microm, 250 mm x 4 mm; mobile phase: methanol-phosphate buffer 25 mmol l(-1), pH 6.5 (15:85, v/v); flow rate--1.2 ml/min; detection UV--298 nm) and UV (294 nm). Specific acid-base catalysis involves: (a) hydrolysis of ertapenem, catalysed by hydrogen ions; (b) hydrolysis of ertapenem dianions catalysed by hydroxide ions; (c) spontaneous hydrolysis of zwitter ions and dianions of ertapenem under the influence of water. The thermodynamic parameters of these reactions--energy, enthalpy and entropy of activation were calculated. It was observed that buffer catalysis occurred in acetate, phosphate and borate buffers.

Acute bacterial cholangitis

Acute bacterial cholangitis refers to a bacterial infection of the biliary tract. Choledocholithiasis is the most common cause of biliary obstruction, with Escherichia coli, Klebsiella spp, and Enterococcus spp the most frequent biliary pathogens isolated in patients with cholangitis. Clinical presentation varies from mild illness to septic shock. The diagnosis of cholangitis is clinical and is supported by laboratory and radiographic findings. Initial treatment is supportive and includes antibiotics to cover the typical pathogens, but definitive treatment requires biliary drainage. Endoscopic retrograde cholangiopancreatography (ERCP) is the preferred technique to achieve biliary decompression with placement of an internal or nasobiliary stent. In cases in which ERCP is unsuccessful or technically not feasible, percutaneous transhepatic biliary drainage (PTBD) is preferred over surgery, which carries significant morbidity and mortality. In order to prevent post-ERCP cholangitis, prophylactic antibiotics are recommended in patients undergoing ERCP for known or suspected biliary obstruction.