前体对纳他霉素生物合成的影响

研究如何通过加入前体来提高生物合成纳他霉素的产量，进行了前体种类选择、前体加入量及加入时间的优化实验，结果表明，丙酸钠是比乙酸钠、丁酸钠、正丙醇更佳的纳他霉素合成前体，乙醇及正丁醇对纳他霉素生物合成无明显促进作用；在发酵24h时向发酵培养基中添加0．6％的丙酸钠．纳他霉素产量达3014．43mg／L，与不添加前体相比提高了185.8％，具有较好的工业应用价值。     

那他霉素粗粉精制工艺优化

目的 优化那他霉素粗粉精制工艺,提高其精粉质量。方法 采用正交对比试验方法,对那他霉素粗粉溶解剂、粗粉溶液浓度、结晶溶液pH、淋洗挖洗影响、挖洗剂种类等精制工艺条件进行优化。结果 成功开发了那他霉素粗粉的精制优化工艺,即：粗粉溶解剂为75%甲醇-水溶液、粗粉溶液浓度为(25000±1000)u/mL、结晶溶液pH为6.0~7.0、结晶后沉淀需要用75%丙酮-水溶液淋洗后再挖洗,该工艺制备的那他霉素精粉纯度高达99.84%、收率可达94.05%,杂质含量为0.2%。结论 那他霉素粗粉精制工艺经优化后,大幅提高了精粉质量,且工艺稳定可行,可用于放大生产。     

发酵液中纳他霉素的提取及鉴定

通过对纳他霉素部分理化性质的研究,建立了溶剂萃取法从发酵液中提取纳他霉素的工艺路线和参数。发酵液经预处理后离心分离收集菌体,加入适量甲醇,调节pH至10.5,离心除去不溶杂质,再调节pH至中性,经蒸发浓缩结晶获得纳他霉素。纳他霉素粗品经进一步纯化后,通过紫外光谱、红外光谱、核磁共振图谱和生物活性检测法进行了分析鉴定。通过该工艺回收的纳他霉素粗品纯度为74.6%±2.95%,回收率达到80.3%±3.27%,较好的保持了其生物活性。结果显示,该工艺在低浓度发酵液中提取纳他霉素达到较为理想的效果。     

Bioanalytical method development and validation of natamycin in rabbit tears and its application to ocular pharmacokinetic studies

A new selective and sensitive high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of natamycin in rabbit tears using amphotericin B as internal standard (IS). Chromatographic separation was achieved on a Luna Cyano column (100 mm × 2 mm, 3 μm) using ammonium acetate buffer (pH 4; 3.5mM): methanol (10:90, v/v) as the mobile phase. The run time was 5 min. Detection was performed by negative ion electrospray ionization in multiple reaction monitoring (MRM) mode. The calibration curve was linear over the concentration range from 25 to 800 ng/ml, and lower limit of detection of 12.5 ng/ml. The accuracy and precision of the method were within the acceptable limit of ± 20% at the lower limit of quantitation and ± 15% at other concentrations. Natamycin was stable during the battery of stability studies viz., bench-top, auto-sampler, freeze/thaw cycles and 30 days storage in a freezer at -70 ± 10 °C. The method was successfully applied to the ocular pharmacokinetic studies of natamycin eye drops in New Zealand rabbit tears.     

5%那他霉素联合0.2%氟康唑治疗真菌性角膜炎65例疗效观察

目的观察联合应用5%那他霉素与0.2%氟康唑治疗真菌性角膜炎的疗效。方法收集2010年1月至2013年1月经角膜病灶取材直接湿片镜检或真菌培养阳性者共65例,根据角膜炎浸润的不同程度将病例分为非严重的中轻度组与严重的重度组,联合应用5%那他霉素与0.2%氟康唑滴眼,每小时各一次,经规范治疗7~10d,视病情继续药物治疗或手术治疗,疗程共7~50d不等。临床检查及疗效判断标准两组相同。结果非严重组24例,治愈23例(95.8%),1例有效(4.2%);严重组41例,治愈12例(29.3%),有效11例(26.8%),无效18例(43.9%)。两组间总的有效率差异具有显著统计学意义(P<0.01)。结论 5%那他霉素联合0.2%氟康唑治疗真菌性角膜炎,特别是对非严重的中轻度者有非常满意的疗效,对严重的真菌性角膜炎也有较为满意的效果。     

纳塔尔链霉菌产纳他霉素发酵条件的优化

采用Plackett-Burman设计、最陡爬坡试验与响应面设计相结合的方法对纳塔尔链霉菌(Streptomyces natalensis)SIPI-120620产纳他霉素的发酵条件进行了优化.结果表明,培养基中的玉米淀粉、葡萄糖和NaC1是影响纳他霉素产量的关键因子.优化后的培养条件为:玉米淀粉70g/L、葡萄糖10.7g/L、黄豆饼粉15g/L、酵母粉20g/L、NaCll.3g/L、碳酸钙2g/L及初始pH6.5.此试验条件下,纳他霉素产量达到4.09g/L,比原培养条件提高了1.86g/L倍.     

Effect of natamycin on cytochrome P450 enzymes in rats

Natamycin is a polyene macrolide antibiotic widely used in the food industry as a feed additive to prevent mold contamination of foods. There are many contradictory results on the genotoxic effects of macrolides which could suggest a potential risk for humans. In the present study, the effects of natamycin on the activities of some drug metabolizing enzymes in rat liver microsomes were determined in vivo. Rats were treated orally with natamycin at doses of 0.3, 1, 3 and 10 mg/kg body weight (bw)/day for 6 days. Determinations of cytochrome P450 (CYP) enzyme activities were carried out in hepatic microsomes isolated from rats treated. The activities of CYP2E1, CYP1A1/2 CYP2B1/2 and CYP4A1/2 enzymes significantly decreased after treatment with 1, 3 and 10 mg/kg bw/day, in a dose-dependent manner as compared to control. This effect was not observed after natamycin treatment at dose of 0.3 mg/kg bw/day. Our results suggest that natamycin may not potentiate the toxicity of many xenobiotics via metabolic activation and/or accumulation of reactive metabolites but also might affect the clearance of other xenobiotics detoxified by the studied CYP enzymes.     

那他霉素滴眼液治疗角膜外伤后真菌性角膜炎

目的观察5％那他霉素滴眼液治疗角膜外伤后真菌性角膜炎的临床疗效。方法经角膜刮片确诊的真菌性角膜炎的37例（37眼）进行病灶刮除并碘酊烧灼联合国产5％那他霉素滴眼液滴眼,观察疗效。结果37例中30例痊愈,7例好转。结论病灶刮除并碘酊烧灼联合国产5％那他霉素滴眼液治疗轻中度外伤性真菌性角膜炎有效。     

5%那他霉素联合0.2%氟康唑治疗真菌性角膜炎疗效观察

目的探讨5%那他霉素联合0.2%氟康唑治疗真菌性角膜炎的临床疗效。方法真菌性角膜炎患者45例（45只眼）按照患者角膜炎侵润程度的不同将其分为非严重的中轻度组（A组）和严重的重度组（B组）,两组患者均给予5%那他霉素联合0.2%氟康唑治疗,对比分析两组疗效。结果 A组总有效率为100.00%明显高于B组的57.14%（χ2=54.7771,P=0.0000）;A组发病至诊治时间为（16.5±6.9）d明显短于B组的（29.8±8.7）d（P〈0.05）;A组经治疗后视力改善明显优于B组（P〈0.05）,差异均有统计学意义。结论 5%那他霉素联合0.2%氟康唑治疗真菌性角膜炎,尤其是治疗非严重的中轻度患者具有显著性效果,能有效地缩短治疗时间。     

角膜基质内注射氟康唑联合匹马霉素滴眼液治疗真菌性角膜炎的疗效观察

目的观察角膜基质内注射氟康唑联合匹马霉素滴眼液治疗真菌性角膜炎的疗效。方法选择常规用药方式治疗无效的真菌性角膜炎患者42例（42只眼）,在匹马霉素滴眼液点眼治疗的基础上采用0.2%氟康唑角膜基质内注射,观察其疗效及不良反应发生情况。结果 42例中36例（85.7%）痊愈,治愈时间为12~30 d,平均（19.3±4.9）d,5例经手术治愈,1例最终摘除眼球。1例患者在第5次注射后突然出现眼部刺激症状,给予双氯酚酸钠滴眼液点眼,2d后症状消失。所有病例随访1~3个月,无穿刺道瘢痕形成,治愈者无复发。结论对常规治疗无效的真菌性角膜炎患者采用角膜基质内注射氟康唑联合匹马霉素滴眼液点眼可取得良好的治疗效果。