Conjugated linoleic acid (CLA) as a functional food: Is it beneficial or not?

Conjugated linoleic acid (CLA) has attracted great attention in recent years as a popular class of functional food that is broadly used. It refers to a group of geometric and positional isomers of linoleic acid (LA) with a conjugated double bond. The main natural sources of CLA are dairy products, beef and lamb, whereas only trace amounts occur naturally in plant lipids. CLA has been shown to improve various health issues, having effects on obesity, inflammatory, anti-carcinogenicity, atherogenicity, immunomodulation, and osteosynthesis. Also, compared to studies on humans, many animal researches reveal more positive benefits on health. CLA represents a nutritional avenue to improve lifestyle diseases and metabolic syndrome. Most of these effects are attributed to the two major CLA isomers [conjugated linoleic acid cis-9,trans-11 isomer (c9,t11), and conjugated linoleic acid trans-10,cis-12 isomer (t10,c12)], and their mixture (CLA mix). In contrast, adverse effects of CLA have been also reported, such as glucose homeostasis, insulin resistance, hepatic steatosis and induction of colon carcinogenesis in humans, as well as milk fat inhibition in ruminants, lowering chicken productivity, influencing egg quality and altering growth performance in fish. This review article aims to discuss the health benefits of CLA as a nutraceutical supplement and highlight the possible mechanisms of action that may contribute to its outcome. It also outlines the feasible adverse effects of CLA besides summarizing the recent peer-reviewed publications on CLA to ensure its efficacy and safety for proper application in humans.

CEACAM1 as a molecular target in oral cancer.

OBJECTIVE: The majority of oral cancer is caused by malignant transformation of squamous cells in surface of the oral mucosa. However, the relationship between CEACAM1 and oral cancer is unclear. METHODS: GSE23558 and GSE25099 profiles were downloaded from gene expression omnibus (GEO). Differentially expressed genes (DEGs) were screened and weighted gene co-expression network analysis (WGCNA) was performed. Construction and analysis of protein-protein interaction (PPI) Network. Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG), gene set enrichment analysis (GSEA), gene expression heatmap, immune infiltration analysis, comparative toxicogenomics database (CTD) were performed. TargetScan screened miRNAs that regulated central DEGs. Western blotting (WB) experiment was performed. RESULTS: 1269 DEGs were identified. According to GO analysis, they were mainly enriched in same protein binding, signal receptor binding, cell surface, epithelial cell development. KEGG analysis showed that they were mainly enriched in cancer pathways, PI3K Akt signaling pathway, TNF signaling pathway, NF kappa B signaling pathway, TGF beta signaling pathway. PPI network showed that 11 genes (CDCA8, CCNA2, MELK, KIF2C, CDC45, HMMR, TPX2, CENPF, CDK1, CEP55, CEACAM1) were obtained. Gene expression heatmap showed that CEP55 and MELK were highly expressed in oral cancer samples. CEACAM1 was lowly expressed in oral cancer samples. CEACAM1, CEP55 and MELK were involved in tumor, inflammation, necrosis, and proliferation. Western blotting (WB) showed that CEACAM1 in oral cancer samples was lower than that in normal samples, after CEACAM1 knockdown, it was lower than that in oral cancer samples. CONCLUSION: CEACAM1 is lowly expressed in oral cancer, the lower CEACAM1, the worse prognosis.

Defibrotide improved the outcome of monocrotaline induced rat hepatic sinusoidal obstruction syndrome.

BACKGROUND AND AIM: Pyrrolizidine alkaloids (PA) induced hepatic sinusoidal obstruction syndrome (HSOS) occurred worldwide and the mortality rate remained high because there were no specific therapies. Defibrotide was effective for HSOS following hematopoietic stem cell transplantation. But the pathogenesis of the two types of HSOS were not equivalent. The purpose of this study was to see if defibrotide was also effective in PA induced rat HSOS. METHODS: First we improved rat HSOS model by using higher dose (230 mg/kg) of monocrotaline (a kind of PA) as the dose of median lethal dose. So drug effectiveness could be assessed by survival time. Next, male SD rats were divided into 5 groups. They were control group, model group, low dose low molecular weight heparin (LMWH) treatment group, high dose LMWH treatment group and defibrotide treatment group. Rats' survival time, liver function, white blood cell count and cytokines were compared among the groups. The DeLeve score was used to assess the severity of liver pathology. RESULTS: The model group exhibited typical liver pathology of HSOS, such as hepatic sinus dilation, congestion, endothelial injury of central lobular vein, coagulative necrosis of hepatocytes and fibrin deposition in the subendothelial. The pathologic characteristics indicated that the model was built up successfully. The survival rate was significantly higher in defibrotide group (81.8%) than model group (43.7%), while the survival rates were similar in the two LMWH groups (62.5% and 75%) and model group. The survival time only be prolonged by defibrotide (P=0.028) but not LMWH (P>0.05). DeLeve score was improved most in the defibrotide group than the two LMWH groups (both P<0.01). Changes in DeLeve score, liver function, plasma level of tumor necrosis factor α and plasminogen activator inhibitor-1 exhibited the same trends. CONCLUSION: Defibrotide could improve the outcome of monocrotaline-induced rat HSOS indicating that defibrotide might be a better choice than LMWH in clinical practice.

Ceruloplasmin inhibits the proliferation, migration and invasion of nasopharyngeal carcinoma cells and is negatively regulated by miR-543.

BACKGROUND: Ceruloplasmin (CP), recognized as a member of multicopper oxidase family, is related to the progression of diverse cancers in human beings. This study is designed to clarify the expression characteristics, biological function and related mechanism of CP in nasopharyngeal carcinoma (NPC). METHODS: CP expression in NPC tissues and cells was probed by quantitative real-time polymerase chain reaction (qRT-PCR), immunohistochemistry (IHC) and Western blot. After gain-of-function and loss-of-function models were established, cell counting kit-8 (CCK-8), Transwell and BrdU assays were employed to measure cell viability, migration and invasion. The targeting relationship between microRNA-543 (miR-543) and CP was verified by dual-luciferase reporter gene assay. RESULTS: As against normal nasopharyngeal epithelial tissues, CP expression was significantly lower in NPC tissues, which was associated with higher clinical stage and the short overall survival time. Compared with the control group, CP overexpression markedly restrained the growth, migration and invasion of NPC cells; knocking down CP had the opposite effect. MiR-543 directly targeted CP and negatively modulated its expression. CONCLUSION: CP restrains the growth, migration and invasion of NPC cells and is negatively regulated by miR-543.

Frankincense vinegar-processing improves the absorption of boswellic acids by regulating bile acid metabolism.

BACKGROUND: Boswellic acids in Olibanum (known as frankincense) are potent anti-inflammatory properties in treating ulcerative colitis (UC), but its low bioavailability limited drug development. Evidence accumulated that vinegar processing of frankincense exerts positive effects on improving absorption of compositions. The underlying mechanism is unknown. In recent decades, spectacular growth and multidisciplinary integration of metabolic application were witnessed. The relationship between drug absorption and curative effect has been more or less established. However, it remains a knowledge gap in the field between drug absorption and endocrine metabolism. PURPOSE: To investigate the enhancement mechanism of vinegar processing in the absorption of boswellic acids via the aspect of bile acid metabolism. METHODS: The effects of raw frankincense (RF) and processed frankincense (PF) were compared by the UC model of rats. The plasma concentration of boswellic acids and the hepatic and colonic bile acids contents were quantified by UPLC-TQ-MS. The levels of mRNA and protein associated with bile acid metabolism were also compared. RESULTS: The results showed that PF exhibited re-markable mitigating effects on UC with the elevated plasma level of boswellic acid and upregulated expression of the absorption-related protein multidrug resistance-associated protein 2 (MRP2) and organic anion transporting polypeptide 1B3 (OATP1B3) in the liver and colon. It improved colonic lithocholic acid (LCA), which promoted the expression of bile acid nuclear receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR), resulting in the upregulation of MRP2 and OATP1B3. CONCLUSION: This paper revealed the mechanisms behind the absorption promotion effects of processing. Bile acids metabolism exhibits potential status in pharmaceutical development. The results shed light on the interdisciplinary collaboration between the metabolism and drug absorption fields.

Metabolism and Mechanism of Human Cytochrome P450 Enzyme 1A2.

Human cytochrome P450 enzyme 1A2 (CYP1A2) is one of the most important cytochrome P450 (CYP) enzymes in the liver, accounting for 13% to 15% of hepatic CYP enzymes. CYP1A2 metabolises many clinical drugs, such as phenacetin, caffeine, clozapine, tacrine, propranolol, and mexiletine. CYP1A2 also metabolises certain precarcinogens such as aflatoxins, mycotoxins, nitrosamines, and endogenous substances such as steroids. The regulation of CYP1A2 is influenced by many factors. The transcription of CYP1A2 involves not only the aromatic hydrocarbon receptor pathway but also many additional transcription factors, and CYP1A2 expression may be affected by transcription coactivators and compression factors. Degradation of CYP1A2 mRNA and protein, alternative splicing, RNA stability, regulatory microRNAs, and DNA methylation are also known to affect the regulation of CYP1A2. Many factors can lead to changes in the activity of CYP1A2. Smoking, polycyclic aromatic hydrocarbon ingestion, and certain drugs (e.g., omeprazole) increase its activity, while many clinical drugs such as theophylline, fluvoxamine, quinolone antibiotics, verapamil, cimetidine, and oral contraceptives can inhibit CYP1A2 activity. Here, we review the drugs metabolised by CYP1A2, the metabolic mechanism of CYP1A2, and various factors that influence CYP1A2 metabolism. The metabolic mechanism of CYP1A2 is of great significance in the development of personalised medicine and CYP1A2 target-based drugs.

A review on the wide range applications of hyaluronic acid as a promising rejuvenating biomacromolecule in the treatments of bone related diseases.

Hyaluronic acid (HA) is a multifunctional high molecular weight polysaccharide produced by synoviocytes, fibroblasts, and chondrocytes, and is naturally found in many tissues and fluids, and more abundantly in articular cartilage and synovial fluid. Naturally occurring HA is thought to participate in many biological processes, such as regulation of cell adhesion and cell motility, manipulation of cell differentiation and proliferation, and providing mechanical properties to tissues (Girish and Kemparaju, 2007). Due to its excellent physicochemical properties such as high viscosity, elasticity, biodegradability, biocompatibility, nontoxicity, and nonimmunogenicity, HA based formulations have a wide range of applications and serves as a promising rejuvenating biomacromolecule in biomedical applications. In recent decades, HA is currently a popular topic, and has been widely used in bone related diseases for its remarkable efficacy in articular cartilage lubrication, analgesia, anti-inflammation, immunomodulatory, chondroprotection, anti-cancer and etc. Moreover, the safety and tolerability of HA based formulations have also been well-documented for treatment of various types of bone related diseases (Chen et al., 2018). This review gives a deep understanding on the special benefits and provides a mechanism-based rationale for the use of HA in bone related diseases conditions with special reference to osteoarthritis (OA), rheumatoid arthritis (RA), bone metastatic cancers.

[Metabolic and excretory process of Citri Reticulatae Pericarpium Viride and Citri Reticulatae Pericarpium in rats' urine and feces analyzed by RRLC-QqQ-MSn].

This present study was to investigate the metabolism and excretion of characteristic polyphenols such as flavonoids and coumarins in urine and feces of rats after intragastric administration of ethanol extracts of Citri Reticulatae Pericarpium Viride and Citri Reticulatae Pericarpium. The urine and feces of rats were collected after intragastric administration of 70% ethanol extracts of Citri Reticulatae Pericarpium Viride and Citri Reticulatae Pericarpium. Rapid resolution liquid chromatography coupled with quadrupole tandem mass spectrometry (RRLC-QqQ-MSn) was applied to compare the contents of polyphenols in ethanol extract, urine and feces. By comparing with reference substance, 30 polyphenols were identified from the ethanol extracts of Citri Reticulatae Pericarpium Viride and Citri Reticulatae Pericarpium, including flavone glycosides, flavones, flavonone glycosides, flavonones, flavonol glycosides, polymethoxyflavones, coumarins, and limonoids and so on. The detection of various types of compounds showed differences in contents between the intestinal metabolism and excretion in the feces after systemic circulatory metabolism and renal excretion. The results showed that the polymethoxyflavones and flavonones were primarily excreted through urine, and the flavonone glycosides and limonoids were primarily excreted through feces. However, coumarins were hardly detected in feces and urine, indicating that coumarins may be metabolized in the body.

MiR-24 promotes migration and invasion of non-small cell lung cancer by targeting ZNF367.

PURPOSE: Non-small lung cancer (NSCLC) is one of most common cancers worldwide. microRNAs (miRNAs) play an important role in animal biological processes, such as cell growth, differentiation and apoptosis. The aim of this study was to investigate whether MiR-24 can regulate cell proliferation of NSCLC by targeting ZNF367. METHODS: Real time quantitative PCR (qRT-PCR) was used to detect the expression levels of MiR-24 and ZNF367. Western blot assay was employed to analyze the protein levels. Luciferase reporter assay was used to test the target gene of MiR-24. MTT assay was used to detect cell proliferation. RESULTS: MiR-24 was significantly up-regulated in NSCLC tissues compared with their corresponding nontumorous tissues (p<0.05). Over-expression of MiR-24 could significantly promoted cell migration and invasion (p<0.05). ZNF367 was a downstream target of MiR-24 and down-regulated by MiR-24. Knockdown of ZNF367 remarkably promoted NSCLC cell proliferation (p<0.05). CONCLUSIONS: The novel identified MiR-24/ZNF367 axis offers new insights into tumorigenesis of NSCLC and a new biomarker for NSCLC treatment.

Signaling pathways involved in the expression of SZNF and the target genes binding with SZNF related to cyadox.

SZNF (Sus scrofa zinc finger CCHC domain containing 3) is a post-transcription regulation factor, belonging to CCHC zinc finger proteins. Cyadox is a novel quinoxaline drug with antibacterial and growth promotion effects. In this study, we investigated the pharmacological mechanism of cyadox mediated by SZNF. Firstly, signaling pathways related to cyadox-induced SZNF expression were studied. The results showed that the mRNA level of SZNF reached the peak as early as 4 h after 2 µM cyadox treatment in swine hepatocytes. Several signaling pathways, including JAK2/STAT1, PI3K/Akt, TGF-ß/Smad3 and p38, might play critical roles in regulation of SZNF. The JAK2/STAT1, JAK2/PI3K/Akt, PI3K/Akt and myD88 & TAK1 & ASK1 /P38 signaling pathways were firstly activated after cyadox treatment in swine hepatocyte, the TGF-ß/Smad3 signaling pathway was activated later. Then given the characteristic of RNA binding of CCHC zinc finger proteins, the target mRNAs binding with SZNF were detected by RNA immunoprecipitation coupled to sequencing (RIP-seq) in PK-15 cells treated with cyadox. The RIP-Seq results showed that the bound mRNAs of 45 genes and 93 genes by SZNF protein were increased and decreased, respectively in cyadox-treated PK-15 cells compared with blank sample. With bioinformatics analysis, we showed that cyadox might exert its antibacterial and growth promotion effect by regulating SZNF-associated target genes in post-transcriptional level, such as genes related to growth (MLXIP, CKS2) and inflammation (LGALS3, PLAU). Thus, our results indicated that SZNF can post-transcriptionally regulate its target genes related to growth and inflammatory in cyadox-treated cells, which may explain the pharmacological mechanism of this drug.

A Convenient and Sensitive LC-MS/MS Method for Simultaneous Determination of Carbadox- and Olaquindox-Related Residues in Swine Muscle and Liver Tissues.

This paper presents a convenient and sensitive LC-MS/MS method for the simultaneous determination of carbadox and olaquindox residues, including desoxyolaquindox (DOLQ), desoxycarbadox (DCBX), quinoxaline-2-carboxylic acid (QCA), 3-methyl-quinoxaline-2-carboxylic acid (MQCA), and the glycine conjugates of QCA and MQCA (namely, QCA-glycine and MQCA-glycine, resp.) in swine muscle and liver tissues. Tissue samples were extracted with 2% metaphosphoric acid in 20% methanol and cleaned up by solid-phase extraction (SPE) on a mixed-mode anion-exchange column (Oasis MAX). Analysis was performed on a C18 column by detection with mass spectrometry in the multiple reaction monitoring (MRM) mode. The limits of detection (LODs) of the six analytes were determined to be 0.01 µg·kg-1 to 0.25 µg·kg-1, and the limits of quantification (LOQs) were 0.02 µg·kg-1 to 0.5 µg·kg-1. The total recoveries of the six analytes in all tissues were higher than 79.1% with the RSD% less than 9.2%. The developed method can determine the real residue level of QCA and MQCA, whether they are present in free form or as glycine conjugates in tissues, together with the carcinogenic desoxy metabolites DCBX and DOLQ with high recovery. Therefore, this method was suitable for routine analysis of residue control programmes and the residue depletion study of CBX and OLQ on swine.

Quality Control of the Fuzi Lizhong Pill Through Simultaneous Determination of 16 Major Bioactive Constituents by RRLC-MS-MS.

Fuzi Lizhong pill (FLP) is used to treat gastritis, and the monarch drug of it is Aconiti Lateralis Radix Praeparata (Fuzi, aconite roots) which is a toxic herbal medicine. To better control the safety and quality of FLP, an effective method to analyze the contents of 16 toxic and bioactive components using rapid resolution liquid chromatography-tandem triple-quadrupole mass spectrometer was established. The 16 constituents included aconine, mesaconine, hypaconitine, benzoylaconine, benzoylmesaconine, benzoylhypaconine, adenosine, liquiritin, liquiritigenin, glycyrrhizic acid, isoliquiritigenin, 6-gingerol, atractylenolide III, atractylenolide I, atractylenolide II and glycyrrhetic acid. Ideal separation was performed using gradient elution in 13 min by optimized conditions. All the isomerides were isolated to baseline. The improved method with a polarity switch in contiguous time segments could analyze the five types of components, including polar and nonpolar compounds, without decreasing sensitivity. The proposed method was fully validated. The results revealed that contents of six alkaloids from Fuzi were significantly different among the samples. Using the established method and multivariate statistical method, the quality consistency of two dosage forms of FLP from different companies were analyzed. The optimized method could be used for the quality control of FLP and investigate index compound variation between two dosage forms.

Analysis of Major Components of Bacitracin, Colistin and Virginiamycin in Feed Using Matrix Solid-phase Dispersion Extraction by Liquid Chromatography-electrospray Ionization Tandem Mass Spectrometry.

A quantitative LC-MS/MS method has been developed for simultaneous determination of bacitracin A, bacitracin B, colistin A, colistin B and virginiamycin M1 in feed. This rapid simple and effective extraction method was based on matrix solid-phase dispersion. Qualitative and quantitative analyses were performed by LC-ESI-MS/MS. CCß of polypeptide antibiotics upon the method ranged from 9.6 to 15.8 µg kg-1 and 19.4 to 27.5 µg kg-1, respectively. The limit of quantification of polypeptide antibiotics was 25 µg kg-1 in feed samples. The recoveries of polypeptide antibiotics spiked in feed samples at a concentration range of 25-100 µg kg-1 were found above 75.9-87.9% with relative standard deviations within days less than 15.7% and between days less than 20.6%. This rapid and reliable method can be used to efficiently separate, characterize and quantify the residues of polypeptide antibiotics in feed with advantages of simple pretreatment and environmental friendly.

Preparation, characterization and pharmacokinetics of cyadox nanosuspension.

An increase in number of newly developed synthetic drugs displays bioavailability constraints because of poor water solubility. Nanosuspensions formulation may help to overwhelm these problems by increasing dissolution velocity and saturation solubility. In the present study, cyadox (Cyx) nanosuspension was successfully prepared by recrystallization based on acid-base neutralization combined with high pressure homogenization method using Polyvinylpyrrolidone K30 (PVP) as stabilizer. The nanosuspension had uniform particle distribution, excellent sedimentation rate and redispersibility. The nanosuspension significantly improved the solubility, dissolution and bioavailability. The saturation solubility of Cyx nanocrystal was higher than that of bulk Cyx and released the total drug in very short time. Further, pharmacokinetics of Cyx nanosuspension and normal suspension following oral administration was investigated in beagle dogs. Nanosuspension improved the bioavailability of Cyx which could be beneficial for intestinal bacterial infection in animals. Maximum concentration and area under concentration time curve were increased with particles size reduction which might give rise to pronounce fluctuations in plasma concentration and more intensified antibacterial effects. The terminal half-life and mean resident time of Cyx nanosuspension had also increased compared to normal Cyx suspension. In conclusion, nanosuspensions may be a suitable delivery approach to increase the bioavailability of poorly soluble drugs.

Highly para-Selective C-H Alkylation of Benzene Derivatives with 2,2,2-Trifluoroethyl α-Aryl-α-Diazoesters.

Compared to the most popular directing-group-assisted strategy, the "undirected" strategy for C-H bond functionalization represents a more flexible but more challenging approach. Reported herein is a gold-catalyzed highly site-selective C(sp2 )-H alkylation of unactivated arenes with 2,2,2-trifluoroethyl α-aryl-α-diazoesters. This protocol demonstrates that high site-selective C-H bond functionalization can be achieved without the assistance of a directing group. In this transformation, both the gold catalyst and trifluoroethyl group on the ester of the diazo compound play vital roles for achieving the chemo- and regioselectivity.

Quinoxaline 1,4-di-N-Oxides: Biological Activities and Mechanisms of Actions.

Quinoxaline 1,4-di-N-oxides (QdNOs) have manifold biological properties, including antimicrobial, antitumoral, antitrypanosomal and antiinflammatory/antioxidant activities. These diverse activities endow them broad applications and prospects in human and veterinary medicines. As QdNOs arouse widespread interest, the evaluation of their medicinal chemistry is still in progress. In the meantime, adverse effects have been reported in some of the QdNO derivatives. For example, genotoxicity and bacterial resistance have been found in QdNO antibacterial growth promoters, conferring urgent need for discovery of new QdNO drugs. However, the modes of actions of QdNOs are not fully understood, hindering the development and innovation of these promising compounds. Here, QdNOs are categorized based on the activities and usages, among which the antimicrobial activities are consist of antibacterial, antimycobacterial and anticandida activities, and the antiprotozoal activities include antitrypanosomal, antimalarial, antitrichomonas, and antiamoebic activities. The structure-activity relationship and the mode of actions of each type of activity of QdNOs are summarized, and the toxicity and the underlying mechanisms are also discussed, providing insight for the future research and development of these fascinating compounds.

Qualitative screening of veterinary anti-microbial agents in tissues, milk, and eggs of food-producing animals using liquid chromatography coupled with tandem mass spectrometry.

A method for the analysis of 120 drugs in animal derived food was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). These analytes belong to 12 families of veterinary anti-microbial agents (quinolones, macrolides, ß-lactams, nitroimidazoles, sulfonamides, lincomycines, chloramphenicols, quinoxalines, tetracyclines, polypeptides, and antibacterial synergists) as well as other compounds not assigned to a particular drug family. The animal derived food samples include muscle and liver of swine, bovine, sheep, and chicken, as well as hen eggs and dairy milk. The sample preparation included ultrasound-assisted extraction (UAE) with acetonitrile-water and a final clean-up with auto solid-phase extraction (SPE) on HLB cartridges. The detection and quantification of 120 anti-microbial agents was performed using LC-MS/MS in positive and negative ion mode. The chromatographic separation was performed on a C18 column using acetonitrile and 0.1% formic acid as the mobile phase. The limit of detection (LOD) and limit of quantification (LOQ) of all drugs in food-producing animals were 0.5-3.0µg/kg and 1.5-10.0µg/kg, respectively. The developed method was successfully utilized to monitor real samples, which demonstrated that it is a simple, fast, and robust method, and could be used as a regulatory to screen for the presence of residues from veterinary anti-microbial drugs in animal-derived foods.

Preparation, characterization and pharmacokinetics of doxycycline hydrochloride and florfenicol polyvinylpyrroliddone microparticle entrapped with hydroxypropyl-ß-cyclodextrin inclusion complexes suspension.

In order to effectively control the bacterial pneumonia in pigs, doxycycline hydrochloride (DoxHcl) and florfenicol (FF) microparticle suspension together with inclusion complexes was prepared by using hydroxypropyl-ß-cyclodextrin (HP-ß-CD) as host molecules, polyvinylpyrroliddone (PVP) as polymer carriers and hydroxypropyl methyl cellulose (HPMC) as suspending agents. In vitro antibacterial activity, properties, stability and pharmacokinetics of the suspension were studied. The results demonstrated that DoxHcl and FF had a synergistic or additive antibacterial activity against Streptococcus suis, Actinobacillus pleuropneumoniae and Haemophilus parasuis. The size, polydispersity index and zeta potential of microparticles were 1.46 ± 0.06 µm, 0.30 ± 0.02 and 1.53 ± 0.04 mV, respectively. The encapsulation efficiency (EE) of DoxHcl and FF was 45.28% ± 3.30% and 89.69% ± 2.71%, respectively. The re-dispersed time and sedimentation rate of the suspension were 1 min and 1. The suspension went through the 9-gage needle smoothly with withdrawal volume of 9.12 ± 0.87 mL/min. The suspension showed good stability when stored away from light, no irritation at the injection site and sustained release in PBS buffer. After intramuscular administration to pig, DoxHcl and FF could maintain over 0.15 µg/mL for 72 h. Compared to the control injection, the suspension increased the elimination half-life (T½ke) as well as mean residence time (MRT) of DoxHcl from 5.73 to 9.77 h and from 12.02 to 18.81 h, and those of FF from 12.02 to 26.19 h and from 12.02 to 28.16 h, respectively. The suspension increased the bioavailability of DoxHcl and FF by 1.74 and 1.13-fold, respectively. These results suggest that the compound suspension is a promising formulation for pig pneumonia therapy.

Metabolism and Disposition of Aditoprim in Swine, Broilers, Carp and Rats.

Aditoprim (ADP) is a newly developed antibacterial agent in veterinary medicine. The metabolism and disposition of ADP in swine, broilers, carp and rats were investigated by using a radio tracer method combined with a radioactivity detector and a liquid chromatography/ion trap/time-of-flight mass spectrometry. After a single oral administration, more than 94% of the dose was recovered within 14 d in the four species. The urine excretion was dominant in swine and rats, making up 78% of the dose. N-monodesmethyl-ADP, N-didesmethyl-ADP, and 10 new metabolites were characterized. These metabolites were biotransformed from the process of demethylation, α-hydroxylation, N-oxidation, and NH2-glucuronidation. After an oral dose for 7 d, ADP-derived radioactivity was widely distributed in tissues, and high concentrations were especially observed in bile, liver, kidney, lung, and spleen. The radioactivity in the liver was eliminated much more slowly than in other tissues, with a half-life of 4.26, 3.38, 6.69, and 5.21 d in swine, broilers, carp, and rats, respectively. ADP, N-monodesmethyl-ADP, and N-didesmethyl-ADP were the major metabolites in edible tissues. Notably, ADP was detected with the highest concentration and the longest duration in these tissues. These findings indicated that ADP is the marker residue and the liver is the residue target tissue.