Relebactam is a synthetic, non-β-lactam β-lactamase inhibitor belonging to the diazabicyclooctane class. It is used in combination with imipenem and cilastatin to restore the antibacterial activity of imipenem against susceptible Gram-negative bacteria producing certain serine β-lactamases. The approved combination is marketed as RECARBRIO.
Relebactam is supplied in the pharmaceutical product as its monohydrate, with the molecular formula C12H20N4O6S·H2O and molecular weight 366.39 g/mol. The FDA describes it as a white to off-white crystalline powder that is soluble in water.
Relebactam, also known as MK-7655, is a diazabicyclooctane β-lactamase inhibitor. It inhibits important class A and class C serine β-lactamases, including KPC, ESBL and AmpC enzymes, thereby protecting imipenem from enzymatic degradation. Relebactam itself does not have significant intrinsic antibacterial activity; its principal pharmaceutical role is to restore or enhance the activity of the companion β-lactam antibiotic.
The FDA identifies pharmaceutical relebactam as a crystalline monohydrate. The active drug combination contains 250 mg relebactam per vial, equivalent to 263 mg relebactam monohydrate.
| Parameter | Value |
|---|---|
| Chemical Name | (1R,2S,5R)-7-oxo-2-(piperidin-1-ium-4-ylcarbamoyl)-1,6-diazabicyclo[3.2.1]octan-6-yl sulfate hydrate |
| CAS Number | 1174018-99-5 |
| Pharmaceutical Hydrate CAS | 1174020-13-3 |
| Molecular Formula | C12H20N4O6S·H2O |
| Molecular Weight | 366.39 g/mol |
| Anhydrous Formula | C12H20N4O6S |
| Anhydrous Molecular Weight | 348.38 g/mol |
| Chemical Class | Diazabicyclooctane β-lactamase inhibitor |
| Appearance | White to off-white powder |
| Physical Form | Crystalline monohydrate |
| Solubility | Soluble in water |
| Therapeutic Category | β-lactamase inhibitor |
The FDA identifies the monohydrate as C12H20N4O6S·H2O with MW 366.39, while FDA substance records map CAS 1174020-13-3 to relebactam monohydrate.
Relebactam is used together with imipenem and cilastatin. The current U.S. label identifies RECARBRIO for susceptible Gram-negative infections including:
Relebactam inhibits serine β-lactamases including KPC, ESBL and AmpC-type enzymes, helping protect imipenem from degradation.
Relebactam is a synthetic small-molecule API and can be characterized using chromatographic and spectroscopic techniques. Published analytical work has demonstrated RP-HPLC determination of relebactam in bulk drug and pharmaceutical formulations, while commercial analytical standards provide HPLC, NMR, MS and other characterization data.
Important quality attributes include:
A published commercial manufacturing study reported production of relebactam at >99% purity with non-detectable oligomeric impurities after process optimization.
Relebactam API manufacturing requires careful control of stereochemistry, hydrate state, related substances and residual impurities. Because the pharmaceutical material is supplied as a monohydrate, water content and solid-state characteristics are important quality considerations.
A reliable analytical program should combine HPLC with spectroscopic and physicochemical characterization to confirm identity, purity and consistency of the API.
Relebactam should be packaged in well-controlled pharmaceutical-grade containers that protect the material from moisture and environmental contamination.
Commercial analytical material is commonly stored under controlled low-temperature conditions. For the finished RECARBRIO product, the FDA specifies storage of vials at 20–25°C, with permitted excursions of 15–30°C. This finished-product storage condition should not automatically be treated as the API drug-substance storage specification.
Typical Relebactam API documentation may include:
Relebactam is an important diazabicyclooctane β-lactamase inhibitor used with imipenem/cilastatin for infections caused by susceptible Gram-negative organisms. Its API quality depends on controlled chemical identity, stereochemical purity, assay, hydrate state, water content and related substances.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 0.5% |
| Residue on Ignition | NMT 0.1% |
| Water Content | NMT 1.0% |