Sixty-day repeated dose toxicity of sinafloxacin in rats and dogs

Toxicity and Toxicokinetics of a Four-Week Repeated Gavage of Levamisole in Male Beagle Dogs: A Good Laboratory Practice Study

Levamisole (LVM) is considered an immunomodulatory agent that has the potential to treat various cancer and inflammation diseases. However, there is still much debate surrounding the toxicokinetic and toxicological information of LVM. Therefore, it is crucial to assess its toxicity to provide useful data for future human LVM risk assessments. In this study, a barrier environment was established under the guidance of good laboratory practice (GLP) at the Fujian Center for New Drug Safety Evaluation. Male beagle dogs were orally administered with 5, 15, and 30 mg/kg of LVM daily for four weeks. Toxicity assessment was based on various factors such as mortality, clinical signs, food and water consumption, body weight, body temperature, electrocardiogram, ophthalmological examination, hematology, serum biochemistry, organ/body coefficients, histopathological study, and toxicokinetic analysis. The results of this study showed that LVM did not exhibit any significant toxicological effects on beagle dogs at the exposure levels tested. A no observed adverse effect level (NOAEL) of LVM was set at 30 mg/kg/day for male beagle dogs, which is equivalent to a 12-fold clinical dose in humans. Moreover, the repeated exposure to LVM for four weeks did not lead to any bioaccumulation. These findings provide valuable insights for future human LVM risk assessments.

Minor diterpene glycosides from the leaves of Stevia rebaudiana

Two new diterpene glycosides in addition to five known glycosides have been isolated from a commercial extract of the leaves of Stevia rebaudiana. Compound 1 (rebaudioside KA) was shown to be 13-[(O-β-d-glucopyranosyl)oxy]ent-kaur-16-en-19-oic acid 2-O-β-d-glucopyranosyl-β-d-glucopyranosyl ester and compound 2, 12-α-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy]ent-kaur-16-en-19-oic acid β-d-glucopyranosyl ester. Five additional known compounds were identified, rebaudioside E, rebaudioside M, rebaudioside N, rebaudioside O, and stevioside, respectively. Enzymatic hydrolysis of stevioside afforded the known ent-kaurane aglycone 13-hydroxy-ent-kaur-16-en-19-oic acid (steviol) (3). The isolated metabolite 1 possesses the ent-kaurane aglycone steviol (3), while compound 2 represents the first example of the isomeric diterpene 12-α-hydroxy-ent-kaur-16-en-19-oic acid existing as a glycoside in S. rebaudiana. The structures of the isolated metabolites 1 and 2 were determined based on comprehensive 1D- and 2D-NMR (COSY, HSQC, and HMBC) studies. A high-quality crystal of compound 3 has formed, which allowed the acquisition of X-ray diffraction data that confirmed its structure. The structural similarities between the new metabolites and the commercially available stevioside sweeteners suggest the newly isolated metabolites should be examined for their organoleptic properties. Accordingly rebaudiosides E, M, N, O, and KA have been isolated in greater than gram quantities.

Effects of parenteral administration of enrofloxacin on electrocardiographic parameters in hospitalized dogs

The effect of enrofloxacin on the QT interval of the electrocardiogram was studied in 30 hospitalized dogs. The experimental group (n = 15) received enrofloxacin parenterally (subcutaneously) at a dose of 5 mg/kg twice daily and amoxicillin-clavulanate intravenously at a dose of 22 mg/kg three times daily. The control group (n = 15) received only amoxicillin-clavulanate. Electrocardiography was carried out for 5 min once daily for 6 days. The QT interval was corrected by four different formulae. No differences were found between the two groups or within each group for the duration of the study. On the last day of the study the average QT interval for the control and experimental groups was 213.2 ms and 202.9 ms, respectively. Enrofloxacin did not cause prolongation of the QT or corrected QT intervals. We can conclude that the parenteral administration of enrofloxacin in non-cardiac dogs does not adversely affect the electrocardiographic indicators (no prolongation of the QT or corrected QT interval) and does not induce ventricular arrhythmias. Parenteral use of enrofloxacin is thus safe and effective in non-cardiac dogs.

Acute and twenty-eight days repeated oral dose toxicity study of besifloxacin in Wistar albino rats

The purpose of this study was to investigate the potential acute and 28-day repeated oral toxicities of besifloxacin (BAF) in Wistar albino rats. In oral acute and repeated dose study, BAF was administered to both sex of rats, at dose levels of 0, 300, 600, 900 mg/kg/day and 0, 100, 200, 500 mg/kg/day, respectively. In the acute study, total white blood cell (WBC) (male, 43.74%; female, 42.60%) and total bilirubin (T-BIL) (male, 80%; female, 60%) were significantly increase, total protein (TP) (male, 23.24%; 27.80%) was significantly decreased, and significant incidence of pericholangitis (male, 83.33%; female, 75%) was shown in males and females of high-dose groups. In repeated oral dose toxicity study, similar type effects were also observed after serum hematological and serum biochemical analysis, whereas additionally sever hepatic injury and focal ulceration in gastric mucosa also observed in high dose groups of both sexes after histopathological analysis. However these toxic effects of besifloxacin were transient and reversible and no-observed adverse effect level (NOAEL) were 300 mg/kg/day for acute and 100 mg/kg/day for repeated dose toxicity study, respectively.

Twenty-eight days repeated oral dose toxicity study of gemifloxacin in Wistar albino rats

The purpose of this study was to investigate the potential toxicity of gemifloxacin by 28-day repeated oral dose in Wistar albino rats. The test article, was administered daily by gavage to male and female rats at dose levels of 0, 50, 100, 200 mg/kg/day. At the end of treatment period, 12 rats/sex/group was sacrificed, while six extra rats/sex in the vehicle control and highest dose groups sacrificed after 14 days recovery period. During the treatment and recovery periods, clinical signs, mortality, body weights, food and water consumption, ophthalmoscopy, urinalysis, phototoxicity, hematology, serum biochemistry, synovial fluid biochemistry, electrocardiogram (ECG), gross findings, organ weights, microscopic examination of synovial fluid, and histopathology were examined. Hematological and serum biochemical investigations revealed a dose-dependent increase in the total white blood cell (WBC), total bilirubin (T-BIL), glucose (GLU), alanine aminotransferase (ALT) and significant decreases in total protein (TP) were observed in both sexes at the same dose, at the end of treatment period, but the levels returned toward normal during the recovery period. Histopathology of talar joint showed that erosion of the articular surface of that joint in both sexes at the end of treatment period at the dose level of 200 mg/kg/day. Degenerative changes in tendinocytes were observed in Achilles tendon of both sexes at the high dose level at the end of treatment period. In histopathological study shows partial effacement of liver architecture and focal ulceration in gastric mucosa at the high dose level at the end of treatment period. Based on these results, it was concluded that 28 days repeated oral dose of gemifloxacin caused increases in the liver weight, WBC count, T-BIL, glucose level, ALT, decreasing the TP, cause chronic hepatitis and acute gastritis, erosion of the articular surface of joint and histopathologic changes in Achilles tendon in rats at the dose level of 200 mg/kg/day.

Spectroscopic studies on the binding of a new quinolone antibacterial agent: sinafloxacin to DNA

The binding of sinafloxacin to DNA has been studied by fluorescence spectroscopy and UV-vis absorption spectroscopy. The variations in the spectroscopic characteristics of sinafloxacin upon addition of DNA were observed. Salt concentration effect, KI quenching, fluorescence polarization, DNA denaturation experiments, melting temperature (T(m)) curves and viscosity measurements were studied to investigate the binding mechanism. It was proved that the fluorescence quenching of sinafloxacin is a result of the formation of sinafloxacin-DNA complex. Quenching constants were determined using the Stern-Volmer equation. From the experiment evidence, the major binding mode of sinafloxacin with DNA was evaluated to be the groove binding.

Optimization and validation of a high performance liquid chromatography method for rapid determination of sinafloxacin, a novel fluoroquinolone in rat plasma using a fused-core C(18)-silica column

A novel, simple and rapid high performance liquid chromatographic method has been developed and validated for the determination of sinafloxacin, a new fluoroquinolone, in rat plasma using 96-well protein precipitation, fused-core C(18)-silica column (4.6mmx50mm, 2.7microm) packed with a new solid support, which is made of 2.7microm particles that consist of a 1.7microm solid core covered with a 0.5microm thick shell of porous silica.The chromatographic separation was achieved with a mobile phase of 20:80 (v/v) of acetonitrile and phosphate buffer (pH=3.0) at a flow rate of 1mlmin(-1). Fluorescence detection was employed with lambda(ex) 295nm and lambda(em) 505nm. Lomefloxacin was used as internal standard (IS). The total analysis time was as short as 3min. The method was sensitive with a limit of detection (LOD) of 2ngml(-1), with good linearity (R(2)=0.9996) over the linear range of 5-500ngml(-1). The intra-day and inter-day precision was less than 5.8% and accuracy ranged from 100.3% to 103.5% for quality control (QC) samples at three concentrations of 10, 50 and 400ngml(-1).The fused-core C(18)-silica column method offered high sample throughput, low injection volume and low consumption of organic solvents. The method was successfully employed in the pharmacokinetic study of sinafloxacin formulation product after tail vein injection to healthy rats.

Cellular and humoral immunodepression in vultures feeding upon medicated livestock carrion

Veterinary pharmaceuticals contained in dead livestock may be ingested by avian scavengers and negatively affect their health and consequently their population dynamics and conservation. We evaluated the potential role of antibiotics as immunodepressors using multiple parameters measuring the condition of the cellular and humoral immune system in griffon (Gyps fulvus), cinereous (Aegypius monachus) and Egyptian vultures (Neophron percnopterus). We confirmed the presence of circulating antimicrobial residues, especially quinolones, in nestlings of the three vulture species breeding in central Spain. Individuals ingesting antibiotics showed clearly depressed cellular and humoral immune systems compared with nestlings from the control areas, which did not ingest antibiotics. Within central Spain, we found that individuals with circulating antibiotics showed depressed cellular (especially CD4(+)and CD8(+)T-lymphocyte subsets) and humoral (especially acellular APV complement and IL8-like) immune systems compared with nestlings without circulating antibiotics. This suggests that ingestion of antibiotics together with food may depress the immune system of developing nestlings, temporarily reducing their resistance to opportunistic pathogens, which require experimental confirmation. Medicated livestock carrion should be considered inadequate food for vultures due to their detrimental consequences on health derived from the ingestion and potential effects of the veterinary drugs contained in them and for this reason rejected as a management tool in conservation programmes.