Sulfonamides (SAs) Hapten Design and Synthesis

Creative Biolabs is an indubitable leader in hapten design and synthesis with our most advanced hapten design platform. To meet the growing demand for the determination of multiple sulfonamides (SAs), we have established one-stop solutions to design and synthesis the best suitable SAs hapten based on molecular modeling technology.

Introduction of Sulfonamides

Sulfonamides (SAs) are a large group of antimicrobial synthetic chemotherapeutic drugs. SAs are widely used in human and veterinary medicine for the treatment and prophylactic purposes of infectious diseases and as growth-promoting feed additives. Currently, more than 30 different SAs are used in human and animal treatment, such as sulfadimethoxine (SDM), sulfadimidine or sulfamethazine (SMZ), and sulfathiazole (STZ). The sulfonamide (-SO2NH-) nitrogen has been designated N1 and the nitrogen of the aromatic amino group (-NH2) has been designated N4. The different synthetic compounds are derivatives of SAs and usually defined as N1-position or N4-position substituted compounds, depending on the substitution of the amido or aromatic amino group.

SAs Hapten as Immunogen

By definition, small compounds like sulfonamide drugs are haptens, SAs are too small as synthesis immunogen to elicit an immune response. They require conjugation to proteins to make them immunogenic aimed at the generation of anti-SAs antibodies. A strategy to obtain antibodies against SAs involves attachment of the hapten linking to protein carriers via the common aromatic amino group of all SAs. Individual R-substitution is distal to maximally expose to antibody acquisition. Additionally, SAs link to the carrier protein through its side chain by diazotization, or by introducing spacer arms such as glutaraldehyde or a succinyl group, leaving the common aromatic amino group unchanged.

Due to inherent property, antibodies generated toward SAs haptens are usually cross-reactive to other haptens of the similar structure of SAs and usually have less specificity. Cross-reactivity can be an advantageous characteristic to generate high-affinity generic antibodies against a group of SAs. To date, structurally different haptens have been synthesized and used for immunization, these haptens are effective to induce a class-specific or a compound-specific antibody response.

Chemical structures of sulfonamides. Fig.1 Chemical structures of sulfonamides. (Wang, 2013)

Design, Modification, and Synthesis Service of SAs Hapten

With the development of computer science, the 3D molecular modeling technique and theoretical models have been applied in hapten design and modification. From 3D molecular models, Creative Biolabs provides the design and modification of hapten and synthesize hapten derivatives, which can obtain more information for structurally relative compounds (such as molecular structure, physicochemical parameters, steric and electronic properties). The corresponding antibody against SAs haptens of structurally related compounds is either specific for class members of the structurally family or able to bind to one special compound. In order to obtain these antibodies, attentions are focused on the design and synthesis of hapten, conjugation to carrier protein, as well as the molecular modeling of the SAs hapten. In addition to the SA's overall size and N1- or N4-substituent structure, the dominant sulfonamide epitope of the immunogen is defined by the linking arm.

  • Design and Modification of Class-specific Hapten at N1 Position
  • The SAs with the comparatively large common aromatic ring moiety at one end of the molecule seem suitable for broad specificity antibody generation. Creative Biolabs can synthesize a set of SAs haptens leaving the specific structure of the SAs unchanged in order to produce broad specificity antibodies with the maximum recognition capability for the most employed SAs.

  • Design and Modification of Compound-specific Hapten at N4 Position
  • It is possible to develop antibodies capable of very high specificities and distinguishing very closely related structures. Owing to the SAs sharing a common p-aminobenzoyl ring moiety with an aromatic amino group at the N4-position, the N4 group can be replaced by chemical groups and converted into a free NH2 group. Creative Biolabs offers the design and modification at N4-position which will help design a more effective hapten to achieve the best compound-specific with a high degree of heterology.

Creative Biolabs has years’ experience in hapten design and synthesis, and we will offer you the best support to help advance your specific hapten synthesis programs. If you are interested in learning more about our services, please feel free to contact us.


  1. Wang, Z.; et al. Monoclonal antibodies with group specificity toward sulfonamides: selection of hapten and antibody selectivity. Analytical and bioanalytical chemistry. 2013, 405(12): 4027-4037.
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