高效液相色谱法同时测定复方对乙酰氨基酚维生素C泡腾片中2组分含量

目的 :建立同时测定复方对乙酰氨基酚维生素C泡腾片中对乙酰氨基酚和维生素C含量的高效液相色谱法。方法 :色谱柱 :YWG -C18柱 (10 μm,2 5 0mm× 4 .6mm) ;流动相 :甲醇 乙腈 0 .0 5mol·L-1磷酸二氢铵 磷酸缓冲液 (5 0∶11∶2 5 0 ) ;流速 :1.0mL·min-1;检测波长 :2 5 4nm。结果 :对乙酰氨基酚线性范围为 8～ 16 0mg·L-1;维生素C线性范围为 5～ 10 0mg·L-1。对乙酰氨基酚回收率为 10 0 .4 % (RSD =2 .4 0 % ) ,维生素C回收率为 10 1.2 % (RSD =1.90 % )。结论 :应用本法同时测定对乙酰氨基酚和维生素C含量 ,具有简便、快速、准确、可靠的特点     

HPLC测定力度申泡腾片中维生素C的含量

目的建立HPLC测定力度申泡腾片中维生素C的含量.方法用Hypersil BDS (5 μm,4.6 mm×250 mm) C18柱;以磷酸盐缓冲液(取磷酸氢二钠15.6 g和磷酸二氢钾12.2 g,加煮沸过的冷水溶解并稀释至2000 ml,用磷酸调pH值至2.5)为流动相;流速0.6 ml/min;检测波长为245 nm;进样量20 μl.结果维生素C进样量在1.62～2. 63 μg范围内与峰面积呈良好的线性关系,相关系数为0.9999.回收率为101.0%,RSD=0.40%(n=9),检测限为10.0 ng.结论方法简便,结果准确,重复性好.     

HPLC测定力度申泡腾片中维生素C的含量

目的 建立HPLC测定力度申泡腾片中维生素C的含量。方法 用Hypersil BDS(5μm,4.6 mm×250 mm)C18柱;以磷 酸盐缓冲液(取磷酸氢二钠15.6 g和磷酸二氢钾12.2 g,加煮沸过的冷水溶解并稀释至2000 ml,用磷酸调pH值至2.5)为流 动相;流速0.6 ml／min;检测波长为245 nm;进样量20μl。结果 维生素C进样量在1.62-2.63μg范围内与峰面积呈良好 的线性关系,相关系数为0.9999。回收率为101.0％,RSD=0.40％(n=9),检测限为10.0 ng。结论 方法简便,结果准确, 重复性好。     

VitC生产技术的研究进展

综述了Vit C（Vit C）生产技术的发展过程和趋势，着重介绍了二步发酵法和葡萄糖直接发酵法的研发现状，并对我国Vit C生产技术的前景进行了展望。     

维生素C注射液抗氧剂的选择

目的　选择维生素 C注射液中的抗氧剂。方法　将 3种抗氧剂 ,分别单用、合用于维生素 C注射液中 ,通过测定维生素 C吸收度 (A)予以比较。结果与结论　复合使用焦亚硫酸纳、L-半胱氨酸、甲醛合次亚硫酸钠等多种抗氧剂有利于药液稳定     

Large scale studies with vitamin C.

The combination of a regular daily supplement of vitamin C with extra dosage at the time of illness has been shown to reduce the disability due to common colds and other winter illness, but we have seen little effect on frequency of infections, sense of (well-being), or levels of serum cholesterol. The variable results that have been obtained from some other trials of vitamin C may be due in part to variation in the initial nutritional state of the subjects, with the greatest effects to be expected where there is most room for improvement. Because of the great variation in individual susceptibility to infection large numbers of subjects are required in these trials and they must be strictly double-blind. Although we have seen no clear evidence of harmful side-effects, occasional sensitivity to large doses of vitamin C cannot be ruled out, and the withdrawal depression of blood levels could conceivably interfere with a patient's ability to handle stress.     

Effect of vitamin C on paracetamol hepatotoxicity

Vitamin C and paracetamol are known to compete for the sulphate pool in the body. Hence the effect of vitamin C on paracetamol hepatotoxicity was studied. In therapeutic doses, simultaneous administration of Vitamin C and paracetamol did not result in liver dysfunction in undernourished subjects as judged by serum GOT and γ-GT levels. On the other hand, even after toxic doses of paracetamol, Vitamin C may have a protective role in mice possibly through its antioxidant property.     

维生素C阴道缓释片的研制

目的:制备维生素C阴道缓释片,并全面考察其质量。方法:以羟丙甲纤维素为缓释材料制备维生素C阴道缓释片,采用紫外分光光度法测定其释放度,高效液相色谱法测定其有关物质和含量,并对其稳定性和局部刺激性进行考察。结果:样品在0.5,1,2 h的释放量分别为标示量的45%~75%,75%~90%,90%以上。高效液相色谱法测定维生素C的平均回收率为99.8%,RSD为0.78%。在各种试验条件下样品的性质稳定。局部无刺激性。结论:该处方工艺合理,质量可控,所得产品质量稳定,局部使用安全性良好。     

维生素C对TRINDER反应的干扰

目的 分析Vitc干扰Trinder反应的原因.方法 采用比较分析法,分析干扰类型.结果 Vitc对Trinder反应的干扰来自于两个方面:1.Vitc与Trinder色原的反应.2.Vitc与H_2O_2的反应.均造成明显的负干扰.结论 实验室克服其干扰有一定困难.建议临床医师选择适当时间测定病人血糖(GLU)、胆固醇(CHOL)、甘油三脂(TG)、高密度脂蛋白胆固醇(HDL-C)、尿酸(UA)等生化检验项目.     

维生素C包衣微丸的制备及稳定性研究

目的制备维生素C微丸 ,并评价其稳定性。方法采用悬浮包衣制剂技术 ,通过均匀设计试验筛选出制备维生素C微丸的处方工艺参数 ,并通过加速试验和长期试验考察其稳定性。结果以枸橼酸及微粉硅胶等为辅料制备维生素C丸芯 ,以丙烯酸树脂为包衣材料 ,包衣液浓度为 4 % ,在进风温度为 5 0℃ ,喷雾压力为 1 4 7× 1 0 5Pa,输液速度为 9 0mL/min的条件下进行悬浮包衣 ,可以制得稳定性良好的维生素C微丸。结论本文研制的包衣微丸为解决维生素C制剂的变色问题作了有益的探索     

Changes in vitamin C and vitamin E during oxidative stress in myocardial reperfusion

Injury to the myocardial tissue due to ischemia and reperfusion occurs because of imbalance between the formation of oxidants and available antioxidants in the heart. Levels of vitamin C (ascorbic acid) and vitamin E (alpha--tocopherol) were evaluated in 52 patients of acute myocardial infarction (AMI) treated by streptokinase. They were further divided into reperfused group (39 patients) and non-reperfused group (13 patients). Twenty normal healthy subjects served as controls. Vitamin C and vitamin E were estimated in study group before and after thrombolytic therapy and in controls. Vitamin C levels were low in AMI cases as compared to controls (8.74 +/- 1.87 and 10.63 +/- 3.26 mg/L, respectively, P < 0.001). Trend of fall in vitamin C levels in the two study groups was not statistically significant. Vitamin E levels declined from 12.19 +/- 6.71 to 9.96 +/- 6.50 mg/L by 4 hours which was significant (P < 0.01) in the reperfused group, but the change in non-reperfused group (9.28 +/- 6.37 to 9.35 +/- 6.07 mg/dL by 4 hours) was non-significant. This is because of increased consumption of this antioxidant in suppressing the oxidative stress which occurs with reperfusion. Vitamin E can be proposed as a valid marker for reperfusion.     

Effect of vitamin E and vitamin C combination on experimental influenza virus infection

Successful antioxidant treatment of the so-called "free radical diseases" has been reported in the literature. In this study we examined the preventive effect of vitamin E and vitamin C, alone and in combination, on the damage caused by influenza virus infection (IVI). Male mice (ICR), infected with influenza virus A/2/68/(H3N2) (1.5 of LD(50)), were administered single once-daily doses of vitamin E (60 mg/kg b.w.) and vitamin C (80 mg/kg b.w.) intraperitoneally (3 days before virus inoculation). On the 5th and 7th day, respectively, after virus inoculation, animals were decapitated. Monooxygenase enzyme activity (ethylmorphine N-demethylase, amidopyrin N-demethylase, analgin N-demethylase, aniline hydroxylase, cytochrome P-450 content and NADPH-cytochrome C reductase [CCR]) was determined in liver 9000 x g supernatant. Primary and secondary products of lipid peroxidation (LPO; conjugated dienes [CD] and TBA-reactive substances) were measured in blood plasma, lung and liver 9000 x g supernatant. Vitamin E effectively restored LPO-levels increased by IVI. The effect of vitamin C was similar, but slighter. The combination (vitamin E + C) had greater effect on LPO levels than their separate administration. P-450-dependent monooxygenase activity was significantly restored and more pronounced cytochrome P-450 content and NADPH-CCR activity was noted. The preventive effect of vitamin E was stronger than the effect of vitamin C, but the combination (vitamin E + C) had the strongest effect. The superior protective effect of the combination is probably due to vitamin C's repairing effect on vitamin E's tocopheroxyl radical.     

Combination treatment with high-dose vitamin C and alpha-tocopherol does not enhance respiratory-tract lining fluid vitamin C levels in asthmatics

Oxidative stress plays a significant role in allergic airway inflammation. Supplementation with alpha-tocopherol (alone or combined with ascorbate/vitamin C) has been assessed as an intervention for allergic airway diseases with conflicting results. Enhancing levels of airway antioxidants with oral supplements has been suggested as an intervention to protect individuals from the effect of inhaled oxidants, although it is unclear whether supplementation changes tocopherol or vitamin C levels in both serum and airway fluids. Our objective was to obtain pilot safety and dosing data from 14 allergic asthmatic volunteers examining the effect of daily combination oral therapy with 500 mg alpha-tocopherol (alpha T) and 2 g vitamin C for 12 wk. We examined serum and airway fluid and cellular levels of alpha- and gamma-tocopherol (gamma T) and vitamin C to plan for future studies of these agents in asthma and allergic rhinitis. Six volunteers completed 12 wk of active treatment with alpha T and vitamin C and 8 completed placebo. Blood and sputum samples were obtained at baseline and at 6 wk and 12 wk of therapy and were analyzed for alpha T, gamma T, and vitamin C levels in the serum, sputum supernatant, and sputum cells. Combination treatment increased serum vitamin C and significantly decreased sputum alpha T and serum gamma T levels. No changes were found in sputum supernatant or sputum cell vitamin C or serum alpha T levels in the active treatment group. In conclusion, supplementation with alpha T and high-dose vitamin C does not augment vitamin C levels in the respiratory-tract lining fluid.     

红外分光光度法鉴别维生素C片

目的建立维生素C片快速、专属的鉴别方法。方法以无水乙醇为溶剂进行提取,采用红外分光光度法(溴化钾压片)进行定性鉴别。结果维生素C片与维生素C对照品的红外吸收光谱完全一致,并与国家药典委员会颁布的《药品红外光谱集》中的维生素C光谱一致。结论本法专属性强、快速、简便。