Cloxacillin benzathine CAS No. 23736-58-5

Product Description

Cloxacillin benzathine is a long-acting form of cloxacillin, a β-lactam antibiotic from the penicillinase-resistant penicillins group. It is a salt form of cloxacillin combined with benzathine to provide a prolonged release of the active drug, making it suitable for intramuscular injection. The IUPAC name is (2S,5R,6R)-6-[[3-(2-chlorophenyl)-5-methyl-1,2-oxazole-4-carbonyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid;N,N'-dibenzylethane-1,2-diamine. It works by inhibiting bacterial cell wall synthesis, targeting penicillin-binding proteins (PBPs), and is effective against penicillinase-producing staphylococci and other Gram-positive bacteria. It is used to treat and prevent infections such as skin and soft tissue infections, osteomyelitis, and rheumatic fever prophylaxis in some cases. However, it is contraindicated in patients with penicillin allergy and should be used with caution in those with renal impairment. It should not be administered intravenously due to the benzathine component. The drug should be stored in a cool, dry place, away from light, and reconstituted solutions should be used within the specified timeframe.

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Product Use & Characteristics

Chemical Information

• Name: Cloxacillin Benzathine

• Type: Salt form of cloxacillin (a semi-synthetic penicillin)

• Molecular Formula: C₅₄H₅₆Cl₂N₈O₁₀S₂

• Molecular Weight: 1112.1 g/mol

• IUPAC Name: (2S,5R,6R)-6-[[3-(2-chlorophenyl)-5-methyl-1,2-oxazole-4-carbonyl]amino]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid;N,N'-dibenzylethane-1,2-diamine

• Common Form: Powder for injection

• Route of Administration: Intramuscular (IM)

• Appearance: White to off-white crystalline powder

• Solubility: Slightly soluble in water and ethanol; freely soluble in methanol

• Physical State: Solid, with low vapor pressure (~5.65×10⁻²⁰ mmHg) and density ~1.56 g/cm³

Pharmacological Properties

• Mechanism of Action: Inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs). It is bactericidal and effective against penicillinase-producing bacteria.

• Beta-lactamase Resistant: Effective against bacteria that produce β-lactamase enzymes.

• Long-acting: The benzathine component slows the release of the active drug, prolonging its effect.

Clinical Uses

• Treatment and Prophylaxis of Infections Caused by:

  • Staphylococcus aureus (including some resistant strains)

  • Streptococcal infections

• Conditions:

  • Skin and soft tissue infections

  • Osteomyelitis

  • Rheumatic fever prophylaxis (in some cases, as an alternative)

Veterinary Use

• Primary Indication: Prevention and treatment of mastitis during the dry period in dairy cows.

• Dosage: One 10 mL syringe (500 mg cloxacillin) per quarter immediately post-last milving; not later than 30 days before calving.

• Labeling & Use: Prescription animal drug—veterinarian supervision required; intramammary infusion only in non-lactating cows.

• Withdrawal Times: No slaughter for food within 30 days after treatment; do not use within 30 days of calving.

Precautions

• Hypersensitivity: Contraindicated in patients with penicillin allergy.

• Use with Caution: In patients with renal impairment.

• Not for Intravenous Use: Due to the benzathine component.

Storage

• Storage Conditions: Should be stored in a cool, dry place, away from light. Reconstituted solutions should be used within the specified timeframe.

• Specific Conditions: Store in airtight/sterile containers between 2–8 °C (powder) or ≤25 °C (formulations); protect from moisture and freezing.

Side Effects

• Allergic Reactions: Rash, anaphylaxis.

• Gastrointestinal Disturbances: Nausea, vomiting, diarrhea.

• Injection Site Pain: Due to IM administration.

Contraindications

• Hypersensitivity to Penicillins or Beta-lactams: Contraindicated in patients with known allergies.

• Renal Impairment: Caution required; dose adjustment may be necessary.

Regulatory Status

• Approval: FDA-approved veterinary NADA #055-058 for dry cow infusion.

• Compliance: Monograph standards in British and U.S. Pharmacopoeias; potency ≥92% and benzathine 20–22%.

Why us!

Qingdao Sigma Chemical Co., Ltd., established in January 2017 and headquartered in Qingdao, China, is a reliable chemical supplier. Specializing in pharmaceuticals, biochemical intermediates, and research chemicals, the company offers a diverse product portfolio, including peptides (e.g., Tirzepatide, Semaglutide), nootropics, veterinary products, and APIs, often marketed with ≥99% purity and COA certification. We provides R&D, custom synthesis, and contract manufacturing services at various scales, while claiming a global export presence across 100+ countries. With international warehouses in the USA, Europe, Australia, and Canada, Qingdao Sigma Chemical also facilitates drop-shipping and reshipments, positioning itself as a key supplier for laboratory and research applications.