Florfenicol is an amide alcohol (chloramphenicol) antibiotic. It is a synthetic thiamphenicol monofluoro derivative. It is a white or off-white crystalline powder, odorless, slightly soluble in water and chloroform; Ethanol, polyethylene glycol 400 and dimethylamide mixed in an appropriate ratio can increase the physical stability of the product in aqueous solution.

【Pharmacological action】

Florfenicol is an animal-specific antibiotic with broad-spectrum, high-efficiency, low-toxicity; good oral absorption, wide distribution in the body (higher concentrations of respiratory and lung drugs), no aplastic anemia.

It is effective against most Gram-negative bacteria, positive bacteria, certain mycoplasmas and strains resistant to chloramphenicol, thiamphenicol, oxytetracycline, sulfonamide and ampicillin, and its antibacterial activity is better than chloramphenicol and A Sulfonemycin. It is highly sensitive to Actinobacillus pleuropneumoniae.

In vitro bacteriostatic test showed that this product is bacteriostatic at low concentration, and can be slowly sterilized at high concentration. The MBC (minimum bactericidal concentration) value for most bacteria is equal to MIC (minimum inhibitory concentration) or 2-4 times of MIC. And have different degrees of antibacterial effect. This product has good curative effect on duck plague and chicken colibacillosis, artificially infected poultry chronic respiratory disease, chick white peony, chicken colibacillosis, various respiratory diseases of cattle, actinobacillus pleuropneumonia, etc. The curative effect is better than that of Thiamphenicol, and can significantly increase the weight gain rate of chicks.

Florfenicol also has a certain effect on atrophic rhinitis and chronic proliferative bowel disease.

【Mechanism of action】

It mainly binds to the 50s ribosomal subunit and inhibits the key enzyme required for protein synthesis, peptidyl acyltransferase, thereby specifically preventing the aminoacyl tRNA from binding to the receptor on the ribosome and inhibiting the elongation of the peptide chain. Somatic proteins cannot be synthesized. Therefore, the rate of inducing endotoxin release is slow and the amount is low, and the sick pig is not heated due to medication.

Florfenicol is mainly a time-dependent antibiotic. To a certain extent, the longer the effective drug concentration in blood or tissue is maintained, the stronger the antibacterial effect. 

【Pharmacokinetics】

This product is absorbed by oral administration and intramuscular injection, and it is widely distributed in the body. The concentration of drug distributed in liver and kidney is higher than that in blood. The concentration of drug in lung, heart, spleen, pancreas and intestine is equivalent to blood concentration in cerebrospinal fluid. The concentration of the drug is low, only 1/4~1/2 of the blood concentration, indicating that the product is suitable for the treatment of systemic infection.

The contents of the stomach affect the rate and extent of absorption of the drug. Therefore, it is best to be administered pre-feeding clinically; when intramuscularly injected, the product can be slowly diffused and absorbed from the injection site. Studies have shown that pigs are given intramuscular or intramuscular injections at the same dose, which can maintain a longer effective blood concentration time than the former.

【Florfenicol Indication】

This product is mainly used for the treatment of various bacterial diseases in pigs, cattle, poultry and fish. Commonly used in pigs for Haemophilus parasuis, Actinobacillus pleuropneumonia, respiratory disease syndrome (PRDC), piglet E. coli diarrhea, porcine atrophic rhinitis and chronic ileitis; can also be used by sensitive bacteria bovine respiratory diseases and mastitis, etc.

It can also be used for sow urinary tract infections, genital tract infections, mastitis and postpartum lactation syndrome.

【Compatibility】

1. This product is not suitable for macrolides (such as tylosin, erythromycin, tilmicosin, guitarmycin, etc.), aminoglycosides, peptides, lincosamides (such as lincomycin) ), vitamin B, iron preparations, etc., otherwise it can produce antagonism.

2. This product cannot be combined with β-lactams (such as penicillins, amoxicillin, cephalosporins) and fluoroquinolones (such as enrofloxacin), because this product is inhibiting bacterial protein synthesis. A quick-acting bacteriostatic agent, the latter being a fast-acting fungicide in the breeding season. Under the former effect, bacterial protein synthesis is rapidly inhibited, and the bacteria stop growing and multiplying, and the bactericidal action of the latter is weakened. Therefore, when the treatment needs to play a rapid bactericidal effect, it cannot be used together.。

3. Avoid using with alkaline drugs to avoid decomposition failure.

4. The combination of florfenicol and doxycycline has a synergistic effect。

5. In theory, florfenicol and tiamulin have antagonistic effects, but this combination of drugs is commonly used clinically. Studies have shown that florfenicol has a significant synergistic effect with tiamulin and/or doxycycline, which is one of the main drug combinations in current farms.

【Comparison of Fukexin with other similar preparations】

Table 1 Comparison of Fukexin with other similar preparations

Figure 1 Comparison of Fukexin with other similar preparations

As can be seen from Figure1, Fukexin and the imported preparations have similar pharmacokinetic characteristics, and the peak plasma concentration and the area under the drug-time curve are significantly higher than the common domestic preparations.

A-Fukexin; B-Imported similar product；C-Domestic similar product

Figure 2 Fukexin and on-site dissolution test of similar products at home and abroad

It can be seen from Fig. 2 that, compared with similar products, Fukexin dissolves in water more quickly and completely, which is very beneficial to the group water medication.

【Fukexin usage】

Usage: Feed or water medication.

Dosage: Oral dose, 20~30mg/kg body weight, 2 times a day.

Single use: add 400 g of this product per ton of feed, add 160 g of this product per ton of drinking water, for 3 to 5 days.

Commonly used drug combinations: Miaokemei (80% tiamulin fumarate), Liduomeixin (50% doxycycline hydrochloride) or tilmicosin, such as:

Nursery, piglet stage (before and after 12 weeks of age): add Miaokemei 125g + 50% Liduomeixin 100g + 20% Fukexin 200g per ton of feed, for 7 to 10 days;

Finishing pigs (before and after 18 weeks of age): Miaokemei 125g + 50% Lidduomeixin 160g + 20% Fukexin 300g per ton of feed, for 7 to 10 days.

【Fukexin safety】

Table 2 Residue test results of Fu Kexin

* Detection limit: 10ng·g-1，**ND indicates that it is not detected

Conclusion: Fukexin was used in poultry for 3 consecutive days. The residual florfenicol in the chest muscle was less than 50μg /kg on the 5th day after stopping the drug. No residual florfenicol was detected in the liver and kidney. No chloramphenicol residues were detected in the pectoral muscle, liver and kidney on days 3, 5, and 7.

【Fukexin Features】

1. High potency: Customized florfenicol raw material, low impurity content, better effect.

2. Good water solubility: The special preparation technology ensures good water solubility and higher dissolution.

3. High bioavailability: Similar bioavailability with imported preparations, peak plasma concentration is twice that of ordinary domestic preparations.

4. Safety: No chloramphenicol residue, florfenicol residue is very low after oral administration.

【Precautions】

1. Florfenicol has embryotoxicity and is contraindicated in pregnant sows.

2. This product does not cause aplastic anemia, but some animals may have short-term adverse reactions such as anorexia, reduced drinking water or diarrhea after administration.

【Withdrawal time】

Florfenicol powder: pig 20 days

【Validity period】

    2 years

【Packing specification】

Content: 20%

Packing: 1000g/can, 12 cans/box; 100g/bag, 100 bags/box