福建地区三种蜂蜜的荧光特性研究

本文研究了福建地区三种蜂蜜(龙眼蜜、荔枝蜜、八叶五加蜜)的稳态荧光光谱,瞬态荧光寿命以及荧光量子产率。稳态荧光光谱研究表明,龙眼蜜和荔枝蜜显示出单一荧光发射峰,其最大发射波长分别为440 nm和430 nm,最大激发波长分别为340 nm和335 nm。八叶五加蜜则显示出双荧光发射峰,发射位置位于363 nm和460 nm,最大激发波长分别位于330 nm和350 nm。瞬态荧光寿命研究显示三种蜂蜜的四个荧光发射峰之间均存在显著差别,其中龙眼蜜和荔枝蜜的荧光寿命分别为8.20±0.13 ns和7.71±0.09 ns,八叶五加蜜的两个荧光发射峰则分别为3.13±0.66 ps和11.20±0.08 ns。量子产率的测定结果显示八叶五加蜜为5.80±0.35%,龙眼蜜和荔枝蜜分别为3.93±0.42%和3.07±0.15%。以上结果表明,不同的蜜种在稳态荧光光谱、荧光寿命、荧光量子产率三个主要的荧光性质上均表现出较大的差异,结合这三个荧光参数有望为蜂蜜的植物源性溯源提供更为丰富、稳定的信息。     

高效液相色谱-紫外串联荧光检测法测定猪饲料中五种β-兴奋剂

采用反相高效液相色谱-紫外串联荧光检测法测定猪饲料中5种β-兴奋剂类药物(克伦特罗、沙丁胺醇、非诺特罗、莱克多巴胺和班布特罗)。用0.1mol/lHCl-甲醇(9+1,V/V)提取药物,旋蒸至干,用0.3%乙酸复溶,正己烷洗涤杂质。用MCX固相萃取柱净化,以C18色谱柱、甲醇-0.1%甲酸水溶液为流动相进行分离;以紫外检测器249nm波长,荧光检测器激发波长226nm、发射波长306nm进行串联检测。方法的检测限为20μg/kg,定量限为50μg/kg,平均回收率范围为86.7%～103.5%,变异系数范围为1.5%～9.5%。     

免疫亲和色谱柱-高效液相色谱法测定饲料中赭曲霉毒素A的研究

本文建立了饲料中赭曲霉毒素A(OTA)的免疫亲和柱净化-高效液相色谱荧光检测方法。样品用甲醇-水(体积比80∶20)提取,通过免疫亲和柱富集和净化,以乙腈和2%乙酸溶液为流动相(体积比44∶56),Agilent C18色谱柱分离,荧光检测器检测(λex-332 nm,λem=460 nm)。OTA的线性范围为0.1～100.0 ng/mL,r=0.99989。方法检测限为0.2μg/kg,定量限为0.6μg/kg。样品中赭曲霉毒素A的加标回收率为75%～92%,相对标准偏差为1.65%～3.61%。     

羊毛角蛋白的分离与纯化

选择白色羊毛为材料,采用还原C法在不同温度下抽提粗蛋白,离子交换层析,SDS-PAGE分析和考马斯亮蓝法测定蛋白含量。结果表明,采用还原C法在72℃抽提3h,经DEAE-纤维素32柱层析,0.3mol/LNaCl洗脱,获得电泳纯的角蛋白组分,其相对分子质量约31ku,蛋白回收率为3.8%。光谱分析表明,该角蛋白组分最大紫外吸收峰约在280nm处,其荧光光谱峰约在346nm处,角蛋白可与Tb3 结合形成配合物,494和549nm处呈现Tb3 特征荧光峰,随着Tb3 浓度的增大,Tb3 敏化荧光逐渐增强并达到饱和。试验为进一步深入研究角蛋白性质和拓宽角蛋白的应用范围奠定了基础。     

高效液相色谱法测定饲料中黄曲霉素B1

试验建立了免疫亲和色谱-高效液相色谱法(HPLC)测定饲料中黄曲霉素B1,采用甲醇-水提取饲料中的黄曲霉素B1,用免疫亲和色谱柱净化,以甲醇和水为流动相,反相高效液相色谱荧光检测法进行测定,激发波长为365nm,发射波长为435nm。方法的检测限为0.01μg/kg,定量限为0.03μg/kg,平均回收率为77.5%,变异系数为0.03%。     

高效液相色谱法测定饲料中莱克多巴胺

本文对饲料中莱克多巴胺的高效液相色谱检测方法进行了研究,采用酸性甲醇-水提取饲料中的莱克多巴胺,用二氯甲烷和正己烷萃取净化,乙腈-水-冰乙酸-戊烷磺酸钠为流动相,反相高效液相色谱荧光检测法进行测定,激发波长226nm,发射波长305nm。方法的检测限为0.48μg/g,定量限为1.60μg/g,平均回收率为89.8%,变异系数为2.16%。     

荧光分光光度法测定当归中阿魏酸含量

目的:探讨荧光分光光度法测定当归中阿魏酸含量的方法。方法:以2%碳酸钠为溶剂,在λex为343nm、λem为463nm处测定当归的荧光强度。结果:阿魏酸含量在0.3-3μg/mL范围内呈良好的线性关系,线性回归方程为y=19.469x+4.8058,r=0.997,阿魏酸对照品在3h内稳定,表明该法灵敏度高、重现性较好,且操作简便。结论:荧光分光光度法可以用于当归药材中阿魏酸含量的测定,且方法简单准确、灵敏度高。     

福建地区三种蜂蜜荧光稳定性研究

研究了福建地区3种主要蜂蜜(龙眼蜜、荔枝蜜、八叶五加蜜)荧光的稳定性,包括金属离子稳定性、热稳定性以及光稳定性。金属离子稳定性考察了8种外加金属离子(Na+、K+、Ca2+、Mg2+、Cu2+、Zn2+、Pb2+、Cd2+)对蜂蜜荧光的影响,结果显示在考察的浓度范围内(200 mg/kg)8种外加金属离子对蜂蜜的荧光强度均没有显著影响。热稳定性考察了三种温度条件下(50℃、70℃、90℃)蜂蜜荧光随加热时间的变化,结果表明在1h的加热时间内50℃和70℃的加热温度对蜂蜜荧光没有显著影响;在90℃加热条件下,蜂蜜荧光出现增强现象,其增强幅度分别为龙眼蜜45%,荔枝蜜21%,八叶五加蜜1 0%。光稳定实验研究了持续紫外光照对蜂蜜荧光的影响,结果显示三种蜂蜜荧光随光照时间延长均出现不同程度光漂白。其中龙眼蜜和荔枝蜜光照30 min后荧光强度分别下降30%和25%,但光谱形状没有显著变化;八叶五加蜜则发现363 nm处荧光发射峰出现光降解现象,其荧光强度下降了54%,且荧光光谱中出现发射波长位于397 nm的新荧光发射峰。该研究表明蜂蜜荧光具有较好的金属离子稳定性和热稳定性,正常蜂蜜生产和加工过程中可能的金属离子或高温接触不会对其荧光产生影响;此外,在应用荧光光谱技术进行蜂蜜相关研究中样品需要避光保存,以避免长期光照对蜂蜜荧光产生漂白或降解。     

中兽药制剂中氟喹诺酮类药物检测方法的研究

本试验旨在建立中兽药制剂中氟喹诺酮类药物的高效液相色谱检测方法。样品经甲醇和0.01 mol/L氢氧化钠提取后,C18柱分离,荧光检测器检测,发射波长278 nm,激发波长465 nm。9种氟喹诺酮类药物在10～2000 ng/mL浓度范围内呈线性相关。在空白样品中添加5~75 mg/kg的浓度,回收率为76.77%～90.31%,批内变异系数为0.45%～4.86%。结果表明,本方法适合中兽药制剂中氟喹诺酮类药物的测定。     

牛奶中氨苄青霉素残留测方法研究

用三氯乙酸溶液沉淀牛奶蛋白并提取氨苄青霉素残留,在酸性条件下,提取液中的氨苄青霉素与甲醛加热生成2-羟基-3-苯基-6-甲基吡嗪(氨苄青霉素荧光衍生物),用带有荧光检测器的高效液相色谱仪在激发波长(Ex)346 nm、发射波长(Em)420 nm条件下测定该衍生物,外标法定量.本方法简单、快速、灵敏度高,最低检测限为1 μg/L,最低定量限为2 μg/L,回收率为70%～110%,批内变异系数在1 0%以内,批间变异系数小于1 5%.     

旋光法测定甲磺酸达氟沙星的含量

采用旋光法测定甲磺酸达氟沙星的含量,结果表明,在6～14 mg/mL浓度范围内,甲磺酸达氟沙星的旋光度与浓度呈良好的线性关系(r=0.999 8).与电位滴定法相比,本法具有简单、快速、易操作等优点.     

禽速康对雏鸡慢性呼吸道病的临床疗效试验

将14日龄艾维茵肉用雏鸡接种感染鸡慢性呼吸道病,然后用禽速康、甲磺酸达氟沙星、罗红霉素、酒石酸泰乐菌素进行混饮给药,比较其疗效.结果试验药物组与感染对照组差异极显著(P＜0.01),试验药物对雏鸡慢性呼吸道病有良好的疗效;禽速康对雏鸡慢性呼吸道病的治疗效果与临床上常用的甲磺酸达氟沙星相当(P＞0.05),比罗红霉素、酒石酸泰乐菌素要好(P＜0.05),且不影响鸡只的正常增重.     

甲磺酸丹诺沙星诱发中国仓鼠肺成纤维细胞（CHL）染色体畸变试验

采用体外培养中国仓鼠肺成纤维细胞（ＣＨＬ）对喹诺酮类经甲磺酸丹诺沙星的诱变性进行了检测，旨在对该药的遗传毒性作出评价，为安全和药提供数据。结果表明：加或不加代谢活化系统Ｓ９，甲磺诺沙星对ＣＨＬ细胞未见致染色体畸变作用。     

达氟沙星脂质体在蛋雏鸡体内的组织动力学及靶向性研究

将260只28日龄试验鸡(体质量215~230 g)随机分成5组:健康对照组20只,甲磺酸达氟沙星溶液静注给药组和内服给药组、甲磺酸达氟沙星脂质体静注给药组和内服给药组,每组60只。以5 mg/kg体质量剂量分别采用静脉注射和内服2种给药途径给予健康蛋雏鸡甲磺酸达氟沙星溶液和脂质体混悬液,于给药后0.167、0.333、0.5、0.75、1、1.5、2、4、6、9、12、24 h各剖杀5只鸡,取血液、肝脏、肾脏、肺脏和肌肉样品。采用反相HPLC色谱内标法测定各组织中达氟沙星浓度。应用MCPKP分析软件处理血浆药物浓度-时间数据,比较2种剂型的组织药动学参数。结果显示,与溶液组相比,甲磺酸达氟沙星脂质体组肝脏、肺脏中的药物分布明显提高,肾脏中的分布降低;通过相对摄取率、靶向效率和峰浓度比3个靶向指标的对比,脂质体组明显提高了肺部靶向性,且在肺部有一定的缓释作用。     

Preparation and evaluation of danofloxacin mesylate microspheres and its pharmacokinetics in pigs

Danofloxacin mesylate gelatin microspheres (DFM-GMS) were prepared by an emulsion chemical crosslinking technique. Distribution of particle size, morphologic characteristics, drug content, and drug stability were evaluated. In-vitro study showed that the release of danofloxacin mesylate (DFM) from microspheres was much slower than from the raw material (DFM) in the release medium. Pharmacokinetic characteristics were evaluated following intramuscular injection of DFM-GMS or DFM in pigs at dosage of 2.5 mg/kg body weight. Elimination half-life (t_1/2β) of the drug was 24.32 h for DFM-GMS, and 6.61 h for DFM (P?<?0.01). Overall, DFM-GMS could be applied as a long-acting and lung targeting dosage form of DFM for clinical application.

     

Pharmacokinetics of danofloxacin and N‐desmethyldanofloxacin in adult horses and their concentration in synovial fluid

The objectives of this study were to investigate the pharmacokinetics of danofloxacin and its metabolite N‐desmethyldanofloxacin and to determine their concentrations in synovial fluid after administration by the intravenous, intramuscular or intragastric routes. Six adult mares received danofloxacin mesylate administered intravenously (i.v.) or intramuscularly (i.m.) at a dose of 5 mg/kg, or intragastrically (IG) at a dose of 7.5 mg/kg using a randomized Latin square design. Concentrations of danofloxacin and N‐desmethyldanofloxacin were measured by UPLC‐MS/MS. After i.v. administration, danofloxacin had an apparent volume of distribution (mean ± SD) of 3.57 ± 0.26 L/kg, a systemic clearance of 357.6 ± 61.0 mL/h/kg, and an elimination half‐life of 8.00 ± 0.48 h. Maximum plasma concentration (C_max) of N‐desmethyldanofloxacin (0.151 ± 0.038 μg/mL) was achieved within 5 min of i.v. administration. Peak danofloxacin concentrations were significantly higher after i.m. (1.37 ± 0.13 μg/mL) than after IG administration (0.99 ± 0.1 μg/mL). Bioavailability was significantly higher after i.m. (100.0 ± 12.5%) than after IG (35.8 ± 8.5%) administration. Concentrations of danofloxacin in synovial fluid samples collected 1.5 h after administration were significantly higher after i.v. (1.02 ± 0.50 μg/mL) and i.m. (0.70 ± 0.35 μg/mL) than after IG (0.20 ± 0.12 μg/mL) administration. Monte Carlo simulations indicated that danofloxacin would be predicted to be effective against bacteria with a minimum inhibitory concentration (MIC) ≤0.25 μg/mL for i.v. and i.m. administration and 0.12 μg/mL for oral administration to maintain an area under the curve:MIC ratio ≥50.     

In vivo and ex vivo assessment of the interaction between ivermectin and danofloxacin in sheep

The impact of an efflux pump-related interaction between ivermectin and danofloxacin on their intestinal transport (ex vivo) and disposition kinetics (in vivo) was assessed. Eighteen male Corriedale sheep were randomly assigned to one of three groups. Animals in Group A received 0.2mg/kg ivermectin by SC injection, those in Group B were given 6 mg/kg danofloxacin SC on two occasions 48 h apart and those in Group C were treated with both compounds at the same rates. Plasma concentrations of ivermectin and danofloxacin were measured by HPLC using fluorescence detection. Ex vivo intestinal drug transport activity was measured by the use of the Ussing chamber technique. Plasma concentrations of ivermectin in the first 6 days after injection tended to be higher in Group C than Group A. Contemporaneous treatment with ivermectin significantly increased systemic exposure to danofloxacin (AUC values were 32-35% higher) and prolonged the elimination half-life of danofloxacin (40-52% longer). Ex vivo, incubation with ivermectin significantly decreased the efflux transport of rhodamine 123, a P-glycoprotein substrate, in sheep intestine, but no significant effect of danofloxacin on transport activity was observed. Evaluation of the interaction of danofloxacin with the breast cancer resistance protein (BCRP) showed that pantoprazole and ivermectin significantly decreased danofloxacin secretion in the rat intestine. Thus, the ivermectin-induced reduction of danofloxacin efflux transport observed in this study may involve BCRP activity but the involvement of P-glycoprotein cannot be ruled out.     

Involvement of breast cancer resistance protein (BCRP/ABCG2) in the secretion of danofloxacin into milk: interaction with ivermectin

Danofloxacin, a veterinary fluoroquinolone antimicrobial drug, is actively secreted into milk by an as yet unknown mechanism. One of the main determinants of active drug secretion into milk is the transporter (BCRP/ABCG2). The main purpose was to determine whether danofloxacin is an in vitro substrate for Bcrp1/BCRP and to assess its involvement in danofloxacin secretion into milk. In addition, the role of potential drug-drug interactions in this process was assessed using ivermectin. Danofloxacin was transported in vitro by Bcrp1/BCRP, and ivermectin efficiently blocked this transport. Experiments with Bcrp1(-/-) mice showed no evidence of the involvement of Bcrp1 in plasma pharmacokinetics of danofloxacin. However, the milk concentration and milk-to-plasma ratio of danofloxacin were almost twofold higher in wild-type compared with Bcrp1(-/-) mice. The in vivo interaction with ivermectin was studied in sheep after co-administration of danofloxacin (1.25 mg/kg, i.m.) and ivermectin (0.2 mg/kg, s.c.). Ivermectin had no significant effect on the plasma levels of danofloxacin but significantly decreased danofloxacin concentrations in milk by almost 40%. Concomitant administration of multiple drugs, often used in veterinary therapy, may not only affect their pharmacological activity but also their secretion into milk, because of potential drug-drug interactions mediated by BCRP.     

Comparative study of the plasma pharmacokinetics and tissue concentrations of danofloxacin and enrofloxacin in broiler chickens

The plasma pharmacokinetics of danofloxacin and enrofloxacin in broiler chickens was investigated following single intravenous (i.v.) or oral administration (p.o.) and the steady-state plasma and tissue concentrations of both drugs were investigated after continuous administration via the drinking water. The following dosages approved for the treatment of chickens were used: danofloxacin 5 mg/kg and enrofloxacin 10 mg/kg of body weight. Concentrations of danofloxacin and enrofloxacin including its metabolite ciprofloxacin were determined in plasma and eight tissues by specific and sensitive high performance liquid chromatography methods. Pharmacokinetic parameter values for both application routes calculated by noncompartmental methods were similar for danofloxacin compared to enrofloxacin with respect to elimination half-life (t1/2: approximately 6-7 h), mean residence time (MRT; 6-9 h) and mean absorption time (MAT; 1.44 vs. 1.20 h). However, values were twofold higher for body clearance (ClB; 24 vs. 10 mL/min. kg) and volume of distribution at steady state (VdSS; 10 vs. 4 L/kg). Maximum plasma concentration (Cmax) after oral administration was 0.5 and 1.9 micrograms/mL for danofloxacin and enrofloxacin, respectively, occurring at 1.5 h for both drugs. Bioavailability (F) was high: 99% for danofloxacin and 89% for enrofloxacin. Steady-state plasma concentrations (mean +/- SD) following administration via the drinking water were fourfold higher for enrofloxacin (0.52 +/- 0.16 microgram/mL) compared to danofloxacin (0.12 +/- 0.01 microgram/mL). The steady-state AUC0-24 h values of 12.48 and 2.88 micrograms.h/mL, respectively, derived from these plasma concentrations are comparable with corresponding area under the plasma concentration-time curve (AUC) values after single oral administration. For both drugs, tissue concentrations markedly exceeded plasma concentrations, e.g. in the target lung, tissue concentrations of 0.31 +/- 0.07 microgram/g for danofloxacin and 0.88 +/- 0.24 microgram/g for enrofloxacin were detected. Taking into account the similar in vitro activity of danofloxacin and enrofloxacin against important pathogens in chickens, a higher therapeutic efficacy of water medication for enrofloxacin compared to danofloxacin can be expected when given at the approved dosages.