Introduction

Florfenicol is a fluorinated, synthetic analog of thiamphenicol and is mainly used in veterinary medicine. It is a broad-spectrum antibacterial that is active against all organisms sensitive to chloramphenicol, gram-positive cocci, gram-negative bacilli, and also other atypical bacteria such as mycoplasma. 

Florfenicol is also used in aquaculture. It is licensed for use in the US for the control of enteric septicemia in catfish. Florfenicol is also used in Europe since the early 2000s,  treating mainly primary or secondary colibacillosis in broiler, and parent flocks. Florfenicol is not allowed to be used in laying hens because of the residue left in eggs. It is also indicated for use in turkey.  The use of florfenicol in horses is not recommended typically because it leads to diarrhea. 

It is marketed by Schering-Plough under the brand name Nuflor and is also available worldwide as a generic. In the US, Nuflor is available as an injectable antibiotic for the treatment of bovine respiratory disease (BRD), (with Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni), bovine interdigital phlegmon (with Fusobacterium necrophorum and Bacteroides melaninogenicus) in cattle.

Chemical features: Florfenicol is a sulfone, secondary alcohol, an organochlorine compound, and a secondary carboxamide. It is derived from a dichloroacetic acid. Below are some key chemical features of florfenicol that help in its identification:  

• Molecular formula: C12H14Cl2FNO4S 

•  Molecular structure: 

•  CAS number: 73231-34-2 

•  Color: The color of the veterinary florfenicol injection is micro-yellow 

Florfenicol spectrum of activity: Florfenicol, a synthetic antibacterial, has a broad spectrum of activity and has shown promise to be used as a replacement for other broad-spectrum anti-bacterial medicines. These include sulphonamides and tetracyclines, which have been associated with residue concerns and toxicity in food animals. 

Uses of florfenicol

• Florfenicol is mainly used for treating cattle, swine, and dogs. It is also used for treating aquatic organisms such as catfish. 

• Florfenicol is highly lipophilic and provides high bioavailability to treat intracellular pathogens by crossing some anatomic barriers. 

• Bio-availability and half-life of florfenicol in various animals:

     - Penetration of florfenicol across the blood–brain barrier in cattle is 46%. 

     - The half-life of florfenicol is 2-3 hours in cattle after IV administration, but it is prolonged to 18 hours after IM injection, and 27 hours after 40 mg/kg subcutaneously. 

      - Florfenicol achieves high concentrations in the lumen of the small intestine and is 89% absorbed when orally administered to milk-fed calves. 

      - In dogs, the half-life of florfenicol is shorter after both IV and oral administration. 

Florfenicol forms and specifications

Florfenicol is available in various forms and specifications in the market. Commonly available formulations are listed below: 

• Florfenicol Powder (98%): Florfenicol powder 98% is used as an API raw material. It is a white crystalline powder which is slightly soluble in DMF, DMSO, Methanol and water. It yields 98% purity upon conducting an assay to establish its purity.

• Florfenicol Powder (99%): This powder is same as florfenicol powder 99%, only with the difference that it yields 99% purity upon conducting an assay to establish its purity.

• Water Soluble Florfenicol (Florfenicol 10% W.S.): Florfenicol 10% W.S. solution is used for oral administration. It is marketed in a bottle packaging of 100 ml and 1000 ml. Each ml of this solution is composed of 100 mg. florfenicol and 1 ml excipient.

• Florfenicol Injection (30%): The injection is used for parenteral administration and marketed as a 100 ml vial. Per ml of florfenicol 30% injection contains 300 mg florfenicol and 1 ml excipient.

• Florfenicol oral solution: florfenicol oral solution 20% is a clear, colorless to light yellow liquid. It is marketed in high density polyethylene bottles of 100 ml, 500 ml and 1000 ml, for medical use. Each ml of this solution contains 200 mg florfenicol. 

• Florfenicol Sodium Succinate (water-soluble): Florfenicol sodium succinate is a white or white-like crystalline powder, odorless and tasteless. It is deliquescent in nature when the air humidity is high. The product is slightly soluble in acetone, ethanol but easily soluble in water. It contains not less than 95% florfenicol.

•  Florfenicol Premix (powder): The premix is a white to off-white, free flowing powder with red and/or black grains dispersed throughout. Per gram of this powder contains 40 mg florfenicol as an active ingredient. It is marketed as LDPE/paper/paper/paper sealed bag containing 25 kg premix. It is prescribed for medical feeding for swine.

• Florfenicol sodium (soluble powder): It is a kind of soluble florfenicol powder which enhances the therapeutic effect of florfenicol. It is simultaneously soluble in water and hence preferred for clinical practice.

Florfenicol powder manufacturers and purchase:

Various manufacturers around the globe follow cGMP guidelines for producing florfenicol. Some key manufacturers include the following:

• Zhejiang Hisoar Pharmaceutical sales Co., Ltd: Zhejiang Hisoar Pharmaceutical Co Ltd is located in Taizhou, Zhejiang province of China. It specializes in producing special active pharmaceutical ingredients (APIs), formulations and fine chemicals, dyes and dye intermediates. The main products of the company are APIs, such as antibiotics, cardiovascular drugs, antidiabetic drugs and fine chemicals, preparations, dyes and intermediates. 

• Masteam Bio-tech Co., Ltd.: Masteam Bio-tech Co.Ltd. specializes in manufacturing and marketing of APIs for animals, and pharmaceutical intermediates. 

• Hubei Pharmaceutical Technology Co., Ltd: Some other manufacturers including Hubei Pharmaceutical Technology are also playing an active part. 

You can purchase florfenicol in bulk from various trustworthy online platforms such as PharmaSources.com. PharmaSources.com is one of the leading vertical e-commerce online pharmaceutical marketplaces. It provides information on quality pharmaceutical products and suppliers for its customers and delivers services to 90,000+ active members. You could find reliable active pharmaceutical ingredients suppliers,  surgical instruments suppliers, and health equipment suppliers on PharmaSources.com. The services are provided globally, across 211 countries and regions. PharmaSources.com sells over 1,600,000 products in 30 major pharmaceutical categories across the supply chain. 

Florfenicol mechanism of action 

Florfenicol is bacteriostatic and binds to the bacterial 50S ribosomal subunit, thus inhibiting the protein synthesis at the peptidyl transferase step. Competitive antagonism may occur when florfenicol is co-administered with macrolide antibiotics, as they share the same site of action. 

Florfenicol resistance genes: Currently, there are nine identified florfenicol resistance genes, namely:

1.     floR

2.     floRv

3.     floSt

4.     fexA

5.     fexB

6.     pexA

7.     cfr

8.     optrA, and 

9.     estDL136

Except for gene cfr and estDL136, which respectively encode a 23S rRNA methyltransferase and a hydrolase, all of the other genes encode exporters.