Pharmacokinetics of florfenicol after intravenous administration in Escherichia coli lipopolysaccharide-induced endotoxaemic sheep

Influence of Escherichia coli lipopolysaccharide-induced endotoxemia on plasma and tissue disposition of florfenicol after intramuscular administration in rabbits

To assess the effects of the acute inflammatory response (AIR) induced by Escherichia coli lipopolysaccharide (LPS) on plasma and tissue disposition of florfenicol (FFC) and its metabolite florfenicol amine (FFC-a), after its intramuscular (IM) administration, twenty-two New Zealand rabbits were randomly distributed in two experimental groups: Group 1 (LPS) was treated with three intravenous doses of 2 μg LPS/kg bw, before an intramuscular dose of 20 mg/kg FFC twenty-four h after the first LPS or SS injection; Group 2 (Control) was treated with saline solution (SS) in equivalent volumes as LPS-treated group. Blood samples were collected before (T0) and at different times after FFC administration. Acute inflammatory response was assessed in a parallel study where significant increases in body temperature, C-reactive protein concentrations and leukopenia were observed in the group treated with LPS. In another two groups of rabbits, 4 h after FFC treatment, rabbits were euthanized and tissue samples were collected for analysis of FFC and FFC-a concentrations. Pharmacokinetic parameters of FFC that showed significantly higher values in LPS-treated rabbits compared with control rabbits were absorption half-life, area under the curve, mean residence time and clearance /F (Cl/F). Elimination half-life and mean residence time of FFC-a were significantly higher in LPS-treated rabbits, whereas the metabolite ratio of FFC-a decreased significantly. Significant differences in tissue distribution of FFC and FFC-a were observed in rabbits treated with LPS. Modifications in plasma and tissue disposition of FFC and FFC-a were attributed mainly to haemodynamic modifications induced by the AIR through LPS administration.

Coptisine Modulates the Pharmacokinetics of Florfenicol by targeting CYP1A2, CYP2C11 and CYP3A1 in the Liver and P-gp in the Jejunum of Rats: A Pilot Study

1. Coptisine (COP) is the main active ingredient of Coptis chinensis. In Chinese veterinary clinics, Coptis chinensis is commonly used alongside florfenicol to treat intestinal infections. The goal of this study was to investigate the impact of COP co-administration on the pharmacokinetics of florfenicol in rats.2. Male Sprague-Dawley rats were orally administered COP (50 mg/kg BW) or sterile water for 7 consecutive days, followed by a single oral dose of florfenicol (25 mg/kg BW) on the 8^th day. Pharmacokinetics of florfenicol were analyzed using non-compartmental methods, while expression levels of cytochrome P450 (CYP) isoforms in the liver and P-glycoprotein (P-gp) in the jejunum were measured using real-time RT-PCR, Western blot and immunohistochemical analyses.3. Co-administration of COP and florfenicol significantly increased AUC_(0-∞), MRT_(0-∞), and C_max of florfenicol, while CLz/F was significantly decreased. COP down-regulated the expression of CYP1A2, CYP2C11, and CYP3A1 in the liver, as well as P-gp in the jejunum.4. These findings suggest that co-administration of COP with florfenicol alters the pharmacokinetics of florfenicol in rats. The down-regulation of CYP and P-gp expression may contribute to this effect. Therefore, the co-administration of COP with florfenicol may enhance the prophylactic or therapeutic efficacy of florfenicol in veterinary practice.

Impact of tectoridin on the pharmacokinetics of florfenicol via targeting cytochrome P450 and P-glycoprotein of rats

Belamcanda chinensis (L.) DC, commonly used with florfenicol in Chinese veterinary clinics for respiratory tract infections, contains the major effective isoflavone, tectoridin (TEC). This study aimed to investigate the impact of TEC co-administration on the pharmacokinetics of florfenicol in vivo.Male rats received oral TEC (50 mg/kg BW) or sterile water for seven days, followed by a single oral dose of florfenicol (25 mg/kg BW) on the 8th day. Non-compartmental methods analysed the pharmacokinetics of florfenicol, while real-time reverse transcription polymerase chain reaction (RT-PCR), Western blot, and immunohistochemical analyses measured expression levels of cytochrome P450 (CYP) isoforms in the liver and P-glycoprotein (P-gp) in the jejunum.TEC significantly decreased florfenicol's AUC(0-∞), MRT(0-∞), t1/2z, Vz/F, and Cmax by 24.75%, 18.43%, 55.47%, 43.05%, and 19.48%, while increasing CLz/F by 33.33%. TEC also up-regulated hepatic CYP1A2 and CYP3A1 mRNA expression, as well as intestinal MDR1, by 1.39-fold, 1.85-fold, and 1.65-fold. This coincided with a respective increase in protein expression by 1.37-fold, 1.39-fold, and 1.43-fold.These findings suggest that TEC-induced alterations in the pharmacokinetics of florfenicol may be attributed to increased CYP and P-gp expression. Further investigations are warranted to understand the implications of these findings on the clinical effectiveness of florfenicol in veterinary practice.

Effects of berberine on the pharmacokinetics of florfenicol and levels of cytochrome P450 3A37, multidrug resistance 1, and chicken xenobiotic-sensing orphan nuclear receptor mRNA expression in broilers

BACKGROUND

Berberine (BBR) is always used in combination with florfenicol for treating avian in China.

OBJECTIVE

This study aims to investigate the effects of BBR on the pharmacokinetics of florfenicol in broilers.

METHODS

Male broilers were randomly divided into the control group and the BBR group (BG). Note that 50 mg/kg BBR or sterile water was orally administrated to broilers. On the 8th day, florfenicol [30 mg/kg body weight (BW)] was orally administered to broilers in both groups. The plasma concentrations of florfenicol were determined by ultra-high-performance liquid chromatography (UHPLC). The levels of cytochrome P450 (CYP) 3A37, multidrug resistance 1 (MDR1), and chicken xenobiotic-sensing orphan nuclear receptor (CXR) mRNA expression in the liver and jejunum were determined by the real-time PCR.

RESULTS

The results showed that the C_max , t_1/2z , MRT_(0-∞) , and AUC_(0-∞) of florfenicol in BG were significantly increased (by 55.71%, 28.32%, 35.19%, and 55.62%, respectively), while the T_max and CLz/F of florfenicol were significantly decreased (by 52.13% and 35.82%, respectively). In BG, the levels of CYP3A37, MDR1, and CXR mRNA expression in the liver were significantly decreased to 0.72-fold, 0.67-fold, and 0.59-fold, respectively, and the corresponding mRNA expression in the jejunum were significantly decreased to 0.66-fold, 0.55-fold, and 0.64-fold levels, respectively, relative to their levels in the control group.

CONCLUSIONS

BBR altered the pharmacokinetics of florfenicol, probably related to its inhibition of CYP3A37, MDR1, and CXR mRNA expression in the jejunum and liver.

Borneol influences the pharmacokinetics of florfenicol through regulation of cytochrome P450 1A2 (CYP1A2), CYP2C11, CYP3A1, and multidrug resistance 1 (MDR1) mRNA expression levels in rats

Borneol is a traditional Chinese medicine. In Chinese veterinary clinics, borneol and its related compounds are often used in combination with florfenicol to treat respiratory infections. This study investigated whether the pharmacokinetics of florfenicol in rats was affected by its concomitant use with borneol. Sprague-Dawley rats were intragastrically administered borneol (50 mg/kg body weight (BW)) or 0.5% carboxymethyl-cellulose sodium for 7 consecutive days, and then intragastrically administered florfenicol (25 mg/kg BW) on the eighth day. Pharmacokinetic studies showed that borneol significantly decreased the area under the concentration-time curve from zero to infinity (AUC_(0-t)), time to reach peak concentration (T_max), and the peak concentration (C_max) values of florfenicol, whereas the values of mean residence time from zero to infinity (MRT_(0-t)), elimination half-life (t_1/2z), apparent volume of distribution fraction of the dose absorbed (Vz), and plasma clearance fraction of the dose absorbed (CLz) were increased significantly. Furthermore, the mRNA expression levels of multidrug resistance 1 (MDR1) and cytochrome P450 3A1 (CYP3A1) in the jejunum and of CYP1A2 and CYP2C11 in the liver were significantly upregulated by borneol. In conclusion, borneol decreased absorption, increased clearance, improved distribution, and increased the mean residence time of florfenicol in rats, possibly through regulating the mRNA expression levels of drug-metabolizing enzymes and efflux transporters.

Bovine Respiratory Disease Treatment Failure: Impact and Potential Causes

Bovine respiratory disease (BRD) is often attributed to complex interactions between the host, pathogen, and the environment. Likewise, many BRD treatment failures result from interactions between the host, pathogen, environment, drug, and drug administrator. Investigating and addressing the underlying causes of BRD treatment failures can improve clinical outcomes and animal welfare of future cases, improve morale of employees, reduce direct costs of dealing with BRD treatment failures, refine antimicrobial prescribing practices, and advance antimicrobial stewardship. This article discusses these interactions and provides guidance to veterinary practitioners on evaluating the success of treatment protocols.

The Impact of Infection and Inflammation on Drug Metabolism, Active Transport, and Systemic Drug Concentrations in Veterinary Species

Within human medicine, it is recognized that the pharmacokinetics (PK) of many compounds can be altered by the presence of inflammation or infection. Research into the reason for these changes has identified pathways that can influence drug absorption, clearance, and tissue distribution. In contrast, far less is known about these relationships within the framework of veterinary medicine. Rather, most of the PK data generated in veterinary species employs healthy subjects, raising the question of whether these studies are founded on an assumption that healthy animal PK reflect that of the diseased animal population. Accordingly, there is a need to explore the PK changes that might be overlooked in studies that recruit only healthy animals to assesses drug PK. To meet this objective, we surveyed the published literature for studies focusing on the impact of disease on the dose-exposure relationships in food-producing and companion animal species. We found that, consistent with humans and laboratory species, both up- and downregulation of the various cytochrome isoenzymes and/or transporters have occurred in response to an increase in inflammatory mediators. These findings suggest that, as observed in human medicine, the potential for differences in the drug PK in healthy versus animal patients points to a need for acquiring a greater understanding of these changes and how they may influence the dose-exposure-response relationships of veterinary pharmaceuticals. SIGNIFICANCE STATEMENT: This review delivers a much-needed summary of published information that provides insights into how disease and inflammation can influence the appropriateness of extrapolating laboratory-based dose-exposure-response relationships to what will occur in the actual veterinary patient. As part of this review, we also examine some of the method-associated issues to be considered when assessing the reported nature and magnitude of these changes.

Effects of anemoside B4 on pharmacokinetics of florfenicol and mRNA expression of CXR, MDR1, CYP3A37 and UGT1E in broilers

Pulsatillae radix, a traditional Chinese medicine (TCM), is often used in combination with florfenicol for treatment of intestinal infection in Chinese veterinary clinics. Anemoside B4 (AB4) is the major effective saponin in Pulsatillae radix. This study aimed to investigate whether the pharmacokinetics of florfenicol in broilers was affected by the combination of AB4. In this study, broilers were given AB4 (50 mg/kg BW), or 0.9% sodium chloride solution by oral administration for 7 days. They were then fed florfenicol orally (30 mg/kg BW) on the eighth day. The results showed that the AUC_(0-∞), MRT_(0-∞), t_1/2z and C_max of florfenicol were significantly decreased, and the Vz/F and CLz/F were significantly increased by AB4; the mRNA expression levels of CXR, CYP3A37 and MDR1 (except CXR and CYP3A37 in the liver) were up-regulated by AB4. In conclusion, AB4 altered the pharmacokinetics of florfenicol, resulting in lower plasma concentrations of florfenicol, this was probably related to the mRNA expression of CXR, CYP3A37 and MDR1 in the jejunum and liver (except CXR and CYP3A37) increased by AB4. The implications of these findings on the effect of traditional Chinese medicine containing AB4 on the effectiveness of florfenicol in veterinary practice deserve study.

Pharmacokinetics of ivermectin in sheep following pretreatment with Escherichia coli endotoxin

The comparative pharmacokinetics of ivermectin (IVM), between healthy and in Escherichia coli lipopolysaccharides (LPS) injected sheep, was investigated after an intravenous (IV) administration of a single dose of 0.2 mg/kg. Ten Suffolk Down sheep, 55 ± 3.3 kg, were distributed in two experimental groups: Group 1 (LPS): treated with three doses of 1 μg LPS/kg bw at -24, -16, and -0.75 hr before IVM; group 2 (Control): treated with saline solution (SS). An IV dose of 0.2 mg IVM/kg was administered 45 min after the last injection of LPS or SS. Plasma concentrations of IVM were determined by liquid chromatography. Pharmacokinetic parameters were calculated based on non-compartmental modeling. In healthy sheep, the values of the pharmacokinetic parameters were as follows: elimination half-life (2.85 days), mean residence time (MRT) (2.27 days), area under the plasma concentration curve over time (AUC, 117.4 ng day^-1 ml^-1 ), volume of distribution (875.6 ml/kg), and clearance (187.1 ml/day). No statistically significant differences were observed when compared with the results obtained from the group of sheep treated with LPS. It is concluded that the acute inflammatory response (AIR) induced by the intravenous administration of E. coli LPS in adult sheep produced no changes in plasma concentrations or in the pharmacokinetic behavior of IVM, when it is administered intravenously at therapeutic doses.

Plasma and tissue disposition of florfenicol in Escherichia coli lipopolysaccharide-induced endotoxaemic sheep

1. The purpose of this study was to understand the effects of the acute inflammatory response (AIR) induced by Escherichia coli lipopolysaccharide (LPS) on florfenicol (FFC) and FFC-amine (FFC-a) plasma and tissue concentrations. 2. Ten Suffolk Down sheep, 60.5 ± 4.7 kg, were distributed into two experimental groups: group 1 (LPS) treated with three intravenous doses of 1 μg/kg bw of LPS at 24, 16, and 0.75 h (45 min) before FFC treatment; group 2 (Control) was treated with saline solution (SS) in parallel to group 1. An IM dose of 20 mg FFC/kg was administered at 0.75 h after the last injection of LPS or SS. Blood and tissue samples were taken after FFC administration. 3. The plasma AUC_0-4 h values of FFC were higher (p = 0.0313) in sheep treated with LPS (21.8 ± 2.0 μg·min/mL) compared with the control group (12.8 ± 2.3 μg·min/mL). Lipopolysaccharide injections increased FFC concentrations in kidneys, spleen, and brain. Low levels of plasma FFC-a were observed in control sheep (C_max = 0.14 ± 0.01 μg/mL) with a metabolite ratio (MR) of 4.0 ± 0.87%. While in the LPS group, C_max increased slightly (0.25 ± 0.01 μg/mL), and MR decreased to 2.8 ± 0.17%. 4. The changes observed in the plasma and tissue concentrations of FFC were attributed to the pathophysiological effects of LPS on renal hemodynamics that modified tissue distribution and reduced elimination of the drug.