In Situ Ophthalmic Gel of Ciprofloxacin Hydrochloride for Once a Day Sustained Delivery

This article focuses on preparation and evaluation of a once a day ophthalmic delivery system for ciprofloxacin hydrochloride based on the concept of pH-triggered in situ gelation. The in situ gelling system involves the use of polyacrylic acid (Carbopol® 980NF) as a phase transition polymer, hydroxypropyl methylcellulose (Methocel® K100LV) as a release retardant, and ion exchange resin as a complexing agent. Ciprofloxacin hydrochloride was complexed with ion exchange resin to avoid incompatibility between drug and polyacrylic acid. The developed formulation was stable, and nonirritant to rabbit eyes and in vitro drug release was found to be around 98% over a period of 24 hours.     

Ocular Poloxamer-Based Ciprofloxacin Hydrochloride In Situ Forming Gels

The purpose of this study was to develop poloxamer-based in situ gelling formulations of ciprofloxacin hydrochloride (HCl) aiming at prolonging corneal contact time, controlling drug release, enhancing ocular bioavailability, and increasing patient compliance. The in situ forming gels were prepared using different concentrations of poloxamer 407 (P407) and poloxamer 188 (P188). Mucoadhesives such as hydroxypropylmethyl cellulose (HPMC) or hydroxyethyl cellulose (HEC) were added to the formulations to enhance the gel bioadhesion properties. The prepared formulations were evaluated for their in vitro drug release, sol–gel transition temperature, rheological behavior, and mucoadhesion force. The in vivo antimicrobial efficacy of selected ciprofloxacin HCl in situ gelling formulations was studied on infected rabbit's eyes and compared with that of the marketed conventional eye drops. The gelation temperature of the prepared formulations ranged from 28.00 to 34.03°C. Increasing the concentrations of P407, HPMC, and HEC increased the viscosity and mucoadhesion force of the preparations and decreased the in vitro drug release. Ciprofloxacin HCl in situ forming gel formulae composed of P407/P188/HPMC (18/13/1.5%, wt/wt), and P407/P188/HEC (18/13/0.5%, wt/wt) showed optimum release and mucoadhesion properties and improved ocular bioavailability as evidenced by an enhanced therapeutic response compared with the marketed conventional eye drops.     

Residues of veterinary antibiotics in manures from feedlot livestock in eight provinces of China

The residue levels of selected fluoroquinolones, sulfonamides and tetracyclines in 143 animal dung samples collected in 2007 from large-scale livestock and poultry feedlots in 8 provinces were determined by using ultrasonic extraction and liquid chromatography. Recoveries from spiked pig dung samples (spike level = 1 mg/kg) ranged from 73.9 to 102.0% for fluoroquinolones, from 81.6 to 92.3% for sulfonamides, and from 57.2 to 72.6% for tetracyclines. Relative standard deviations of the recoveries were less than 10% within the same day. Method quantification limits were measured from 0.031 to 0.150 mg/kg for fluoroquinolones, from 0.023 to 0.082 mg/kg for sulfonamides, and 0.091 to 0.182 mg/kg for tetracyclines in spiked pig manure samples. Analysis of 61 pig, 54 chicken and 28 cow dung samples collected in China revealed that in pig and cow dung, up to 33.98 and 29.59 mg/kg ciprofloxacin, 33.26 and 46.70 mg/kg enrofloxacin, 59.06 and 59.59 mg/kg oxytetracycline, and 21.06 and 27.59 mg/kg chlortetracycline could be detected, respectively. A maximum concentration of 99.43 mg/kg fleroxacin, 225.45 mg/kg norfloxacin, 45.59 mg/kg ciprofloxacin and 1420.76 mg/kg enrofloxacin could be detected in chicken dung. No appreciable sulfonamide antibiotic concentrations (less than 10 mg/kg) were found in any animal dung, and only sulfadimidine was observed, at a maximum concentration of 6.04 mg/kg, in chicken dung. Both enrofloxacin and chlortetracycline were detected with a very high occurrence in three animal manure samples. The residue levels for most antibiotics showed significant statistical differences among the sampling districts and the animal species.     

光谱法研究Zn（Ⅱ）存在下环丙沙星与DNA的相互作用

在模拟生理条件下,用紫外光谱法和荧光光谱法研究了Zn（Ⅱ）存在下环丙沙星（CPFX）与鲱鱼精DNA的相互作用,初步探讨了环丙沙星、Zn（Ⅱ）在生物体内与DNA相互作用的机理。结果表明,Zn（Ⅱ）和鲱鱼精DNA均可使环丙沙星的荧光强度发生猝灭,其中DNA对CPFX的荧光猝灭作用是形成基态复合物的静态猝灭;在Zn（Ⅱ）存在下,DNA对环丙沙星的荧光猝灭作用显著增强,Zn（Ⅱ）在一定浓度范围内对CPFX与DNA的结合具有促进作用;根据荧光猝灭双倒数图计算了二元、三元体系的结合常数和结合位点数;DNA与CPFX-Zn2＋配合物之间的结合应为沟槽式结合。     

CCl_4增强超声降解环丙沙星的效果及路径解析

研究考察了CCl4增强超声降解喹诺酮类抗生素环丙沙星的效果,通过·OH浓度的测定和异丙醇对反应的抑制情况探索环丙沙星的超声降解机理;采用UPLC/MS/MS方法对降解产物进行分析,解析环丙沙星的降解路径。结果表明,CCl4增强了环丙沙星的超声降解,当反应液体积为100 m L,超声40 min,随着CCl4添加浓度的增大(0~41.4mmol·L-1),环丙沙星的降解率由0.51%增至50.92%;荧光探针分析和异丙醇抑制结果表明增强作用主要在于·OH和一系列氯自由基的氧化;UPLC/MS/MS分析发现,降解过程中生成8种产物,其中包括3种氯代产物,环丙沙星按照6种途径进行降解。研究结果有助于深入研究CCl4增强超声降解抗生素的机理,提高过程处理效果。     

“类乒乓球”状壳聚糖微球对环丙沙星的控制释放性能的研究

以甲醛作为交联剂,通过悬浮交联法得到单分散性的微米级微球。采用分光光度法研究了壳聚糖微球对环丙沙星的载药释药性能,考察了环丙沙星初始浓度、pH、微球粒径大小、载药时间及温度对饱和吸附量的影响。结果表明,在初始浓度为200 mg/L,pH为8.80和时间为65 min,温度为37℃的优化条件下,壳聚糖微球对环丙沙星的载药量最大,最大吸附量为325 mg/g。在pH为7.4,温度为37℃的模拟人体肠胃缓冲溶液(NaH2PO4/NaOH)中研究了初始浓度以及释放时间对释放结果的影响。实验表明,环丙沙星在担载时与环丙沙星的初始浓度有关,浓度越大,担载量越大,但是担载效率和浓度之间无确定的线性关系。在环丙沙星释放初期有明显的释放现象,但是随着时间的推移,药物释放逐渐稳定,释药效率可达97%左右。     

HPLC-DAD法检测化妆品中的氧氟沙星与环丙沙星

建立反相高效液相色谱同时测定化妆品中的氧氟沙星与环丙沙星方法。以十八烷基硅烷键合硅胶为填充剂,以0.025mol/L磷酸溶液(三乙胺调pH至3.0)-乙腈(88:12)为流动相。样品峰与氧氟沙星对照品峰的DAD扫描图谱进行比对鉴别,293nm、277 nm分别作为氧氟沙星、环丙沙星含量测定的检测波长。氧氟沙星在2.03~101.31μg/mL范围内与峰面积线性关系良好(r=0.99995),环丙沙星在1.99~101.31μg/mL范围内与峰面积线性关系良好(r=0.99996);样品峰与氧氟沙星对照品峰的DAD匹配系数为1000。氧氟沙星、环丙沙星的回收率为90.0%~102.0%,RSD为1.7%~4.0%。本法快速、准确、可用于化妆品中擅自添加的氧氟沙星与环丙沙星的鉴别及含量测定。     

反相高效液相色谱法对猪肉组织中恩诺沙星和环丙沙星残留量检测的改进

利用配有荧光检测器的高效液相色谱同时分析动物组织中恩诺沙星及其代谢产物环丙沙星的含量.研究结果表明:环丙沙星、恩诺沙星的质量浓度在2μg/L～100μg/L范围内呈线性关系,相关系数分别为0.9993和0.9991,该方法中恩诺沙星和环丙沙星的最低定量限均为2μg/Kg(S/N=10),恩诺沙星的回收率为85%～90%,环丙沙星的回收率为92%～99%.     

冻干鲤鱼粉中恩诺沙星和环丙沙星残留测定的两种前处理方法比较

采用固相萃取和液液萃取结合超高效液相色谱-串联质谱法(UPLC-MS/MS),对冻干鲤鱼粉中恩诺沙星和环丙沙星残留量进行测定,比较两种前处理方法的测定结果。固相萃取法:样品经EDTA-Mcllvaine缓冲溶液提取,HLB固相萃取柱净化,氮气浓缩;液液萃取法:样品经酸性乙腈溶液提取,正己烷液液萃取净化,旋转蒸发浓缩。两种方法的提取液浓缩定容后,以超高效液相色谱-串联质谱仪测定,外标法定量。固相萃取和液液萃取法的回收率分别为95%～112%和75%～90%,RSD分别为2.9%～7.4%和1.0%～4.6%,检出限分别为1.0μg/kg和0.1～0.2μg/kg。结果表明,两种方法简便快速、重现性好、选择性强,均适用于鱼肉和冻干鲤鱼粉中恩诺沙星和环丙沙星残留的测定。