Cefapirin Sodium (CAS 24356-60-3): Pharmacological Properties, Antibacterial Mechanism, and Research Applications

Cefapirin sodium, also known as cephapirin sodium, is the sodium salt of cefapirin (cephapirin), a first-generation cephalosporin antibiotic belonging to the β-lactam class. Its antibacterial activity is associated with the inhibition of bacterial cell-wall peptidoglycan synthesis through the inactivation of penicillin-binding proteins (PBPs). Cefapirin sodium has been investigated extensively in veterinary medicine, particularly in studies of bovine mastitis, antimicrobial susceptibility, intramammary drug distribution, and bacteriological treatment outcomes.

This article reviews the chemical identity, pharmacological mechanism, and major research applications of cefapirin sodium, with emphasis on peer-reviewed veterinary studies and authoritative chemical databases. It also provides commonly used synonyms and identifiers to facilitate literature retrieval and compound identification. Finetech Industry Limited lists Cefapirin Sodium under product code FT-0603005 for research and pharmaceutical-related sourcing inquiries.

Keywords: Cefapirin Sodium; Cephapirin Sodium; CAS 24356-60-3; FT-0603005; β-lactam antibiotics; penicillin-binding proteins; bovine mastitis; antimicrobial susceptibility testing; veterinary pharmacology; antibiotic resistance research.

1. Chemical Identity and Nomenclature

Accurate compound identification is essential for pharmaceutical research, analytical chemistry, and antimicrobial investigations. Cefapirin sodium is listed in PubChem and the US Food and Drug Administration's Substance Registration System under the preferred name Cephapirin Sodium [1,2].

Chemical information

1. Product name: Cefapirin Sodium
2. Alternative name: Cephapirin Sodium
3. CAS Number: 24356-60-3
4. Molecular formula: C₁₇H₁₆N₃NaO₆S₂
5. Molecular weight: approximately 445.44 g/mol
6. Chemical class: First-generation cephalosporin; β-lactam antibiotic
7. Product code: FT-0603005
8. IUPAC name: Sodium (6R,7R)-3-(acetyloxymethyl)-8-oxo-7-[(2-pyridin-4-ylsulfanylacetyl)amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate [1]

Common synonyms and related search terms

Researchers and procurement professionals may encounter the following names in chemical databases, scientific publications, and supplier catalogs:

1. Cefapirin sodium
2. Cephapirin sodium
3. Cephapirin sodium salt
4. Sodium cephapirin
5. Sodium cefapirin
6. Cephapirin monosodium salt
7. Cefapirin sodium salt
8. Cefapirin sodium [USAN]
9. BL-P 1322
10. BLP 1322
11. Sodium 7-(pyrid-4-ylthioacetamido)cephalosporanate
12. 7-(α-(4-pyridylthio)acetamido)cephalosporanic acid sodium salt
13. Cefadyl (historical or trade-name reference)
14. CAS 24356-60-3

These names are documented across chemical and regulatory databases, although individual synonyms may vary in prevalence and context [1,2]. They should be used to support compound identification rather than assumed to represent different chemical substances.

For database searches, the CAS number and molecular formula are particularly useful for distinguishing cefapirin sodium from the parent compound cefapirin, which has a different molecular formula and molecular weight.

2. Structural Characteristics and Pharmacological Classification

Cefapirin sodium contains the characteristic cephalosporin nucleus, consisting of a β-lactam ring fused to a sulfur-containing dihydrothiazine ring. Its structure also includes an acetoxymethyl substituent and a 4-pyridylthioacetamido side chain [1].

The β-lactam ring is central to its antibacterial activity. Structural interactions between the β-lactam moiety and bacterial penicillin-binding proteins interfere with the enzymatic reactions required for normal cell-wall assembly.

As a sodium salt, cefapirin sodium is used in pharmaceutical and analytical contexts where the salt form is specified. Its actual solubility, solution stability, and compatibility with a particular experimental system should be established using the relevant product specification and validated analytical methods rather than inferred solely from its ionic form.

3. Mechanism of Antibacterial Action

3.1 Inhibition of bacterial cell-wall synthesis

Cefapirin sodium acts through the established mechanism of β-lactam antibiotics. It binds to susceptible penicillin-binding proteins, a group of bacterial enzymes involved in the final stages of peptidoglycan synthesis and cell-wall remodeling.

By inhibiting these enzymes, cefapirin disrupts the transpeptidation reactions responsible for cross-linking peptidoglycan strands. This weakens the structural integrity of the bacterial cell wall and can lead to cell lysis and bacterial death in susceptible organisms [1].

3.2 Bactericidal activity and spectrum considerations

Cefapirin is classified as a first-generation cephalosporin with activity against susceptible Gram-positive bacteria and certain Gram-negative bacteria. However, antibacterial activity is organism- and strain-dependent. The presence of β-lactamase enzymes, alterations in PBPs, and other resistance mechanisms can affect susceptibility.

It is therefore inappropriate to assume that cefapirin sodium is effective against every strain of a particular bacterial species. In experimental work, conclusions should be based on the organisms tested, validated susceptibility methods, and the relevant interpretive criteria.

4. Research Applications

4.1 Bovine mastitis and dairy microbiology

One of the best-documented applications of cefapirin sodium is research into bovine mastitis, an inflammatory condition of the mammary gland commonly associated with bacterial infection.

Cefapirin sodium has been studied as an intramammary antibiotic in lactating dairy cows. In the United States, the approved labeling specified in 21 CFR § 526.365 identifies susceptible strains of Streptococcus agalactiae and Staphylococcus aureus as target organisms for the relevant lactating-cow formulation [3]. Approved indications and conditions of use vary by jurisdiction and formulation.

Peer-reviewed research provides several examples of its relevance to dairy science:

1. Comparative treatment studies: Tomazi et al. evaluated intramammary cefapirin sodium against a combination antimicrobial treatment in a randomized field trial involving nonsevere clinical mastitis. The investigators compared bacteriological and clinical outcomes, illustrating the importance of evaluating individual endpoints rather than treating all measures of therapeutic success as equivalent [4].
2. Comparison of cephalosporins: A separate noninferiority trial compared intramammary cephapirin sodium with ceftiofur hydrochloride. Results differed according to pathogen group and outcome, highlighting the importance of pathogen-specific interpretation in mastitis research [5].
3. Pharmacokinetic investigations: Studies have examined cefapirin concentrations in milk following intramammary administration, including differences between healthy and infected mammary quarters. These investigations help characterize local drug exposure and its relationship to in-vitro antimicrobial activity [6].

Together, these studies establish cefapirin sodium as a relevant compound for investigating veterinary antimicrobial pharmacology, mammary-gland drug distribution, and bacterial infection outcomes.

4.2 Antimicrobial susceptibility and resistance research

Cefapirin sodium is relevant to investigations of bacterial susceptibility to β-lactam antibiotics. Depending on the study design, researchers may evaluate minimum inhibitory concentrations (MICs), compare susceptibility patterns among bacterial isolates, or investigate associations between in-vitro susceptibility and observed treatment outcomes.

Constable and Morin studied whether antimicrobial susceptibility testing could predict clinical duration and bacteriological cure in dairy cows treated for mastitis with cefapirin and other treatment regimens. Their findings indicated that the relationship between in-vitro susceptibility and clinical outcomes depended on the bacterial group and treatment context [7].

This distinction is important: an MIC result is a laboratory measurement, not a guarantee of clinical success or failure. Interpretation requires appropriate test methodology, quality control, organism identification, and validated veterinary interpretive criteria where available.

For laboratory research, cefapirin sodium may therefore be relevant to:

1. Comparative studies of β-lactam antibacterial activity.
2. Evaluation of susceptibility patterns in bacterial isolates.
3. Research on the relationship between MIC values and treatment outcomes.
4. Studies of antimicrobial resistance in veterinary pathogens.
5. Investigation of factors that influence antibiotic exposure and activity.

For veterinary antimicrobial susceptibility testing, laboratories should consult the applicable Clinical and Laboratory Standards Institute (CLSI) guidance and use organism- and drug-specific criteria where established [8].

4.3 Veterinary pharmacokinetics and pharmacodynamics

Pharmacokinetic and pharmacodynamic (PK/PD) research examines how drug exposure relates to antimicrobial activity. For cefapirin sodium, relevant questions include the concentration achieved in milk after administration, the persistence of the active compound, and the relationship between drug exposure and the MIC of target organisms.

The study by Ziv and colleagues examined foremilk pharmacokinetics and antimicrobial activity following intramammary cefapirin administration in healthy and Staphylococcus aureus-infected cows [6]. Such work illustrates how drug distribution, infection status, and time-dependent exposure can inform the interpretation of antimicrobial performance.

Cefapirin sodium can consequently be a useful research compound for studies investigating:

1. Local antibiotic distribution in mammary tissue and milk.
2. Drug concentration–time profiles.
3. Relationships between antimicrobial exposure and bacterial susceptibility.
4. Variability in pharmacological responses across experimental conditions.

The results of such studies are specific to their experimental designs and should not be extrapolated to other formulations, species, or routes of administration without supporting evidence.

4.4 Analytical chemistry and pharmaceutical research

Beyond biological studies, cefapirin sodium may be investigated in analytical and pharmaceutical research where its identity, assay, purity, or stability must be evaluated.

Potential analytical objectives include:

1. Confirming chemical identity using appropriate spectroscopic or chromatographic methods.
2. Developing or evaluating quantitative HPLC methods.
3. Investigating impurities and degradation products.
4. Assessing sample stability under defined storage and handling conditions.
5. Supporting method development for pharmaceutical and veterinary research materials.

The appropriate analytical method depends on the intended measurement and the applicable specification. A chromatographic assay alone does not necessarily establish structural identity, and analytical results should be interpreted alongside reference materials and method validation data.

5. Research Handling and Quality Considerations

The reliability of experiments involving cefapirin sodium depends on documented material identity, suitable storage, and fit-for-purpose analytical characterization.

Before use, researchers should review the supplier's product specification, certificate of analysis (CoA), safety data sheet (SDS), recommended storage conditions, and any relevant handling precautions. Particular attention should be paid to the stated assay, water content where applicable, and the suitability of the material for the intended analytical or biological procedure.

Cefapirin sodium is an antibacterial agent and should be handled in accordance with institutional laboratory safety procedures. Experiments involving live microorganisms should follow the applicable biosafety requirements.

Product information: Finetech Industry Limited lists Cefapirin Sodium under product code FT-0603005, CAS 24356-60-3. Batch-specific purity, analytical methods, packaging options, and availability should be confirmed against the current product documentation.

6. Conclusion

Cefapirin sodium (CAS 24356-60-3) is a first-generation cephalosporin antibiotic whose mechanism involves the inhibition of bacterial cell-wall synthesis. Its research significance is particularly evident in bovine mastitis studies, veterinary antimicrobial susceptibility investigations, and pharmacokinetic research.

Published studies demonstrate that its performance must be interpreted in the context of the target organism, drug exposure, study endpoints, and applicable susceptibility criteria. These considerations make cefapirin sodium relevant to researchers investigating β-lactam pharmacology, veterinary microbiology, and antimicrobial resistance.

Finetech Industry Limited provides Cefapirin Sodium under product code FT-0603005 for research and pharmaceutical-related sourcing inquiries. Researchers are encouraged to consult the current product specification and analytical documentation when evaluating its suitability for a particular study.

References

1. National Center for Biotechnology Information (NCBI). PubChem Compound Summary: Cephapirin Sodium, CID 23675312. Chemical identity, molecular formula, molecular weight, synonyms, and mechanism of action. https://pubchem.ncbi.nlm.nih.gov/compound/Cephapirin-Sodium
2. U.S. Food and Drug Administration. Substance Registration System: Cephapirin Sodium. UNII 431LFF7I7J. https://precision.fda.gov/uniisearch/srs/unii/431LFF7I7J
3. Electronic Code of Federal Regulations. 21 CFR § 526.365 — Cephapirin sodium. https://www.ecfr.gov/current/title-21/section-526.365
4. Tomazi, T., Lopes, T. A. F., Masson, V., Swinkels, J. M., & Santos, M. V. (2018). Randomized noninferiority field trial evaluating cephapirin sodium for treatment of nonsevere clinical mastitis. Journal of Dairy Science, 101(8), 7334–7347. https://doi.org/10.3168/jds.2017-14002
5. Apparao, M. D., Oliveira, L., & Ruegg, P. L. (2013). Noninferiority trial comparing a first-generation cephalosporin with a third-generation cephalosporin in the treatment of nonsevere clinical mastitis in dairy cows. Journal of Dairy Science. PubMed record: https://pubmed.ncbi.nlm.nih.gov/23958017/
6. Ziv, G., et al. (2014). Pharmacokinetics in foremilk and antimicrobial activity of cephapirin following intramammary administration in healthy and Staphylococcus aureus-infected cows. PubMed record: https://pubmed.ncbi.nlm.nih.gov/24224523/
7. Constable, P. D., & Morin, D. E. (2002). Use of antimicrobial susceptibility testing of bacterial pathogens isolated from the milk of dairy cows with clinical mastitis to predict response to treatment with cephapirin and oxytetracycline. Journal of the American Veterinary Medical Association, 221(1), 103–108. https://doi.org/10.2460/javma.2002.221.103
8. Clinical and Laboratory Standards Institute (CLSI). VET06: Methods for Antimicrobial Susceptibility Testing of Infrequently Isolated or Fastidious Bacteria Isolated From Animals. https://clsi.org/shop/standards/vet06/

Disclaimer: This article is provided for scientific and informational purposes only. It is not a substitute for veterinary advice, approved product labeling, or regulatory guidance. Product specifications and availability should be verified with Finetech Industry Limited.