β-lactam; cell wall synthesis

Meropenem functions by binding to and deactivating penicillin-binding proteins (PBPs), thereby inhibiting the synthesis of bacterial cell walls. Meropenem is intrinsically stable against dehydropeptidase-1 (DHP-1) degradation. While Meropenem exhibits broad-spectrum in vitro activity against a variety of Gram-positive, Gram-negative, and anaerobic bacteria, it is ineffective against methicillin-resistant Staphylococcus aureus, Enterococcus faecium, and Stenotrophomonas maltophilia[2].

The incidence of pancreatic infection is significantly reduced by treatment with meropenem (60 mg/kg; intraperitoneal injection; once; SD rats)[3].

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There was no difference in serum amylase levels between AP induced groups (P > 0.05). Pancreatic histology scores were significantly low in rats treated with deferoxamine (group 4), and combination regimen (group 5) (P < 0.001). Meropenem significantly reduced the incidence of pancreatic infection. Although combination of deferoxamine with meropenem showed better effects than meropenem alone in terms of pancreatic infection, the difference did not reach to statistical significance. Conclusions: Meropenem treatment reduces secondary pancreatic infections in acute pancreatitis. Treatment with deferoxamine and meropenem combination may be more beneficial than single therapies in reducing the severity of pancreatitis. Further studies investigating the effects of this combination on survival are needed[Pancreas. 2003 Oct;27(3):247-52.].

Meropenem, a new carbapenem, was compared with imipenem and seven other broad-spectrum antimicrobial agents against approximately 1000 clinical isolates. Meropenem was two- to four-fold more active than imipenem against Gram-negative organisms and its spectrum of antimicrobial activity was wider than those of all other drugs tested. However, imipenem was more potent than meropenem against the staphylococci, Streptococcus spp. and enterococci. Many rarely isolated organisms were more susceptible to the carbapenems than to other comparison compounds. All anaerobic bacteria were inhibited by meropenem at less than or equal to 8 mg/l and 50% of strains were inhibited by 0.25 mg/l. Meropenem MICs were not significantly influenced by high inocula and the drug was generally bactericidal. Strains producing various beta-lactamases remained susceptible to meropenem but some isolates producing high levels of chromosomally-mediated enzymes showed an inoculum effect only at 10(7) cfu/ml. Meropenem demonstrated antagonism with several other beta-lactams against strains producing Type I cephalosporinases. Susceptibility tests performed on agar and in broth produced very similar meropenem results. Imipenem and meropenem shared a high degree of cross-susceptibility as measured by dilution test methods. Disc diffusion (10-micrograms disc) regression-line correlations with meropenem MICs are reported with two possible sets of interpretive criteria, using meropenem breakpoints of less than or equal to 2 and less than or equal to 4 mg/l[5].

Meropenem, a new parenteral carbapenem demonstrated increased activity as compared to imipenem against 336 strains of Neisseria gonorrhoeae, 119 strains of Haemophilus influenzae, and 110 strains of H. ducreyi. Neither carbapenem was affected by the beta-lactamase activity of the organisms tested. Ceftriaxone and ciprofloxacin demonstrated activity superior to that of both carbapenems while the activity of ceftazidime was similar to that of meropenem[1].

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Meropenem is a parenteral carbapenem antibiotic which has excellent bactericidal activity in vitro against almost all clinically significant aerobes and anaerobes. Its high activity is explained by ease of entry into bacteria combined with good affinity for essential penicillin binding proteins, including those associated with cell lysis. Breadth of spectrum is due, in part, to stability to all serine-based beta-lactamases, including those which hydrolyse third-generation cephalosporins. Meropenem has an antibacterial spectrum which is broadly similar to that of imipenem but, whilst slightly less active against staphylococci and enterococci, it is more active against Pseudomonas aeruginosa, all Enterobacteriaceae and Haemophilus influenzae. Amongst common human pathogens, only methicillin-resistant staphylococci and Enterococcus faecium are uniformly resistant to meropenem. The meropenem MICs for penicillin-resistant Streptococcus pneumoniae are higher than for penicillin-susceptible strains but the organisms remain susceptible. Clinical susceptibility in vitro to meropenem is defined by MICs of < or = 4 mg/L, intermediate susceptibility by MICs of 8 mg/L and MICs of > or = 16 mg/L define resistance; equivalent figures for zones of growth inhibition are > or = 14 (susceptible), 12-13 (intermediate) and < or = 11 (resistant) mm. Studies in guinea pig models of systemic infection and infections localised to the lungs, urinary tract and the central nervous system, some of which used immunocompromised animals, confirm the potential of meropenem demonstrated in vitro. These factors, combined with the human plasma, tissue or urinary concentrations of meropenem which exceed modal MICs for the pathogens isolated in clinical trials for most or all of the recommended 8 h dosing interval, predict that meropenem should be efficacious in the treatment of infections at many body sites [4].

Animal Model: Acute necrotizing pancreatitis was induced in male Sprague-Dawley rats weighing 250–350 g.
Dosage: 60 mg/kg
Administration: Intraperitoneal injection; once
Result: The incidence of pancreatic infection was significantly decreased.

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One hundred male Sprague-Dawley rats were randomly divided into 5 groups. All rats underwent laparotomy with cannulation of biliopancreatic duct. Group 1 received intraductal saline injection. Acute necrotizing pancreatitis was induced in group 2, 3, 4, and 5 by intraductal injection of 3% taurocholate. Group 1 (sham operated) and group 2 were injected with saline of 0.3 mL/kg intraperitoneally (i.p). Group 3 was injected with meropenem 60 mg/kg/d i.p, group 4 with deferoxamine 80 mg/kg/d s.c and group 5 with combination of these 2 agents at the same doses. While meropenem was started 2 hours later, all treatments were started immediately after the induction of pancreatitis. All rats were killed at the 48th hour of the treatment and blood and tissue samples were collected for amylase determinations, pathologic examinations, and culture.[3]

Absorption, Distribution and Excretion
Route of Elimination
Approximately 70% of the intravenously administered dose is recovered as unchanged meropenem in the urine over 12 hours, after which little further urinary excretion is detectable.

Approximately 70% of the intravenously administered dose is recovered as unchanged meropenem in the urine over 12 hours, after which little further urinary excretion is detectable. Urinary concentrations of meropenem in excess of 10 ug/mL are maintained for up to 5 hours after a 500 mg dose.

Meropenem is distributed into most body tissues and fluids, including bronchial mucosa, lung, bile, gynecologic tissue (endometrium, myometrium, ovary, cervix, fallopian tube), muscle, heart valves, skin, interstitial and peritoneal fluid, and CSF. Plasma protein binding is approximately 2%. The drug is partially metabolized to at least one microbiologically inactive metabolite. About 70% of an IV dose is eliminated in urine as unchanged drug by tubular secretion and glomerular filtration.

At the end of a 30 minute intravenous infusion of a single dose of Meropenem for injection (IV) in healthy volunteers, mean peak plasma concentrations of meropenem are approximately 23 ug/mL (range 14-26) for the 500 mg dose and 49 ug/mL (range 39-58) for the 1 g dose. A 5-minute intravenous bolus injection of Meropenem for injection (IV) in healthy volunteers results in mean peak plasma concentrations of approximately 45 ug/mL (range 18-65) for the 500 mg dose and 112 ug/mL (range 83-140) for the 1 g dose. Following intravenous doses of 500 mg, mean plasma concentrations of meropenem usually decline to approximately 1 ug/mL at 6 hours after administration. No accumulation of meropenem in plasma was observed with regimens using 500 mg administered every 8 hours or 1 g administered every 6 hours in healthy volunteers with normal renal function.

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Metabolism / Metabolites
Primarily excreted unchanged. There is one metabolite which is microbiologically inactive.
There is one metabolite of meropenem that is microbiologically inactive.

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Biological Half-Life
Approximately 1 hour in adults and children 2 years of age and older with normal renal function. Approximately 1.5 hours in children 3 months to 2 years of age.
The plasma half-life of meropenem is approximately 1 hour in adults with normal renal function and 1.5 hours in children 3 months to 2 years of age. Plasma half-life is increased and clearance of the drug is decreased in patients with renal impairment.

Hepatotoxicity
Serum aminotransferase elevations have been reported in 1% to 6% of recipients of intravenous meropenem when given for up to 14 days. These elevations are usually transient, mild and asymptomatic; and rarely require dose adjustment. Meropenem has also been linked to rare cases of cholestatic jaundice that usually arises after 1 to 3 weeks of therapy. Immunoallergic features may be present, but are rarely prominent. Autoantibodies are rare. Most cases are mild and self-limited, but at least one instance of vanishing bile duct syndrome related to meropenem therapy has been published (Case 1). Meropenem has not been reported to cause acute liver failure.
Likelihood score: D (possible rare cause of clinically apparent liver injury).

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Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Although no information is available on the use of meropenem during breastfeeding, milk levels appear to be low and beta-lactams are generally not expected to cause adverse effects in breastfed infants. Occasionally disruption of the infant's gastrointestinal flora, resulting in diarrhea or thrush have been reported with beta-lactams, but these effects have not been adequately evaluated. Vaborbactam, which is available in combination with meropenem in the product Vabomere, has not been studied in nursing mothers, but the combination is expected to have similar concerns as with meropenem alone.

◉ Effects in Breastfed Infants
A mother received meropenem 1 gram IV every 8 hours for 7 days while exclusively breastfeeding her newborn. When questioned later, she stated that her infant had no oral thrush, watery diarrhea, or diaper dermatitis that required antifungal therapy during the month following her meropenem therapy.
An infant was breastfed (extent not stated) until the 4th month postpartum. At 2 months of age, his mother was given a 2-week course of tobramycin and meropenem (dosage not specified) for a cystic fibrosis exacerbation. The infant displayed no change in stool pattern during the maternal treatment and had normal renal function at 6 months of age.

◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

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Interactions
Case reports in the literature have shown that co-administration of carbapenems, including meropenem, to patients receiving valproic acid or divalproex sodium results in a reduction in valproic acid concentrations. The valproic acid concentrations may drop below the therapeutic range as a result of this interaction, therefore increasing the risk of breakthrough seizures. Although the mechanism of this interaction is unknown, data from in vitro and animal studies suggest that carbapenems may inhibit the hydrolysis of valproic acid's glucuronide metabolite (VPA-g) back to valproic acid, thus decreasing the serum concentrations of valproic acid. If administration of Meropenem for injection is necessary, then supplemental anti-convulsant therapy should be considered

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Protein Binding: Approximately 2%.

[1]. J Antimicrob Chemother. 1989 Sep;24 Suppl A:183-6.

[2]. Drugs. 2007;67(7):1027-52.

[3]. Pancreas. 2003 Oct;27(3):247-52.

[4]. J Antimicrob Chemother.1995 Jul;36 Suppl A:1-17.

[5]. J Antimicrob Chemother.1989 Sep;24 Suppl A:9-29.

[6]. Pharm Res.2001 Sep;18(9):1320-6.

Meropenem trihydrate is a hydrate. It has a role as an antibacterial drug. It contains a meropenem.
Meropenem is a broad-spectrum carbapenem with antibacterial properties, synthetic Meropenem inhibits cell wall synthesis in gram-positive and gram-negative bacteria. It penetrates cell walls and binds to penicillin-binding protein targets. Meropenem acts against aerobes and anaerobes including Klebsiella, E. coli, Enterococcus, Clostridium sp.. (NCI04)
A thienamycin derivative antibacterial agent that is more stable to renal dehydropeptidase I than IMIPENEM, but does not need to be given with an enzyme inhibitor such as CILASTATIN. It is used in the treatment of bacterial infections, including infections in immunocompromised patients.
See also: Meropenem (annotation moved to).

C17H31N3O8S

437.51

383.151

C, 46.67; H, 7.14; N, 9.60; O, 29.25; S, 7.33

119478-56-7

Meropenem;96036-03-2;Meropenem-d6;1217976-95-8; 96036-03-2 (free); 119478-56-7 (hydrate); 211238-34-5 (sodium)

441129

White to yellow solid powder

1.4±0.1 g/cm3

627.4±55.0 °C at 760 mmHg

333.2±31.5 °C

0.0±4.2 mmHg at 25°C

1.639

-2.59

6

10

5

29

679

6

S([C@]1([H])C([H])([H])N([H])[C@]([H])(C(N(C([H])([H])[H])C([H])([H])[H])=O)C1([H])[H])C1=C(C(=O)O[H])N2C([C@]([H])([C@@]([H])(C([H])([H])[H])O[H])[C@@]2([H])[C@@]1([H])C([H])([H])[H])=O

CTUAQTBUVLKNDJ-OBZXMJSBSA-N

InChI=1S/C17H25N3O5S.3H2O/c1-7-12-11(8(2)21)16(23)20(12)13(17(24)25)14(7)26-9-5-10(18-6-9)15(22)19(3)4;;;/h7-12,18,21H,5-6H2,1-4H3,(H,24,25);3*1H2/t7-,8-,9+,10+,11-,12-;;;/m1.../s1

(4R,5S,6S)-3-(((3S,5S)-5-(dimethylcarbamoyl)pyrrolidin-3-yl)thio)-6-((R)-1-hydroxyethyl)-4-methyl-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid trihydrate

Meropenem trihydrate; Meropenem hydrate; ICI 194660; ICI-194660; ICI194660; SM-7338; 119478-56-7; Meropenem (trihydrate); FV9J3JU8B1; (4R,5S,6S)-3-{[(3S,5S)-5-(dimethylcarbamoyl)pyrrolidin-3-yl]sulfanyl}-6-[(1R)-1-hydroxyethyl]-4-methyl-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid trihydrate; UNII-FV9J3JU8B1; MFCD08600005; SM-7338; SM 7338; SM7338; Vabomere.

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~100 mg/mL (~228.57 mM)
H2O : ~12.5 mg/mL (~28.57 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.71 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (5.71 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (5.71 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 100 mg/mL (228.57 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)