Design and Synthesis of Haptens for Florfenicol

With years of experience in antibody development, Creative Biolabs provides small molecule hapten design, modification, and synthesis services for florfenicol, and we also provide small molecule antibody production services for customers all over the world.

Introduction of Florfenicol

Florfenicol (FF), is a broad-spectrum, bacteriostatic antibiotic that is commonly used in veterinary clinical practice or aquacultural practice. It inhibits bacterial protein synthesis by irreversibly binding to the 50S ribosomal subunit and inhibiting peptidyl transferase activity. FF is a derivative of chloramphenicol (CAP) in which FF substitutes the hydroxyl group at the C-3 site with a fluorine atom. The structure of FF is shown in Fig.1. CAP, FF, and thiamphenicol (TAP) together form the chloramphenicol antibiotics (CAPs).

FF is active at lower concentrations than TAP and CAP against many bacterial pathogens in vitro and many CAP-resistant or TAP-resistant strains that are commonly infected with livestock. Due to its broader spectrum of activity and low toxicity, FF has become a better antibacterial agent to replace CAP and TAP. Today, FF has been increasingly used in livestock and aquaculture to treat bacterial diseases related to respiratory pathogens, such as Actinobacillus pleuropneumoniae, Bordetella bronchiseptica, Mannheimia haemolytica, Pasteurella multocida, and Streptococcussuis, etc.

Structures of florfenicol. Fig.1 Structures of florfenicol. (Xu, 2015)

Design and Synthesis of Haptens for Florfenicol

Substances with a molecular weight of less than 1,000 are often not antigenic. However, antibodies can be raised to small molecules by immunizing with a conjugate composed of a low molecular weight substance (hapten) which is covalently linked to proteins carries. FF is a small-molecule substance that can cause an immune response only when combined with a carrier molecule. Based on our extensive knowledge in immunogenicity, the structure of antigenic determinants, and antibody development, we provide comprehensive hapten design and synthesis services for FF. Our hapten design and synthesis services cover the following areas:

  • Carrier: The carrier chosen should be immunogenic and contain a sufficient number of amino acids with reactive side chains to bind small molecules. Commonly used protein carriers include globulin, serum albumin, hemocyanin, ovalbumin, thyroglobulin, and fibrinogen of various species. Haptens are conjugated with different carrier proteins to obtain immunogens and coating antigens using the active ester method.
  • Coupling strategy: The coupling strategy is defined based on the reaction site present on the hapten and the carrier. We will select the most suitable position of the hapten for coupling to improve the sensitivity and immunogenicity of the immunogen.
  • Optimal epitope density: Optimal epitope density is also called the number of haptens linked to the carrier. The hapten density of the conjugate affects the immune response against the antigen. A large number of studies have found that antibody titers with epitope densities in the 8 to 25 range are relatively high, and the optimal density depends on the structure and properties of the molecule.
  • Spacer: The length of the spacer limits steric hindrance and helps to enhance the immunogenicity of the hapten-carrier conjugate. Therefore, when designing small molecule antigens, the selection of the optimal spacer is also critical.

As a leader in small molecule hapten synthesis, Creative Biolabs provides hapten design and synthesis services for multiple small molecules, including antibiotics, toxins, pesticides, antiparasitics, hormones, heavy metals and food additives. Please contact us for more information.


  1. Xu, N.; et al. Development and characterisation of an ultrasensitive monoclonal antibody for chloramphenicol. Food and agricultural immunology. 2015, 26(3): 440-450.
All listed services and products are for Research Use Only. Do Not use in any diagnostic or therapeutic applications.


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