硝酸钾浓度对发酵法生产利福平-SV的效价影响的研究

利福霉素-SV(Rifanmycin)是广谱抗生素之一，也是合成利福平、利福定等抗结核药的中间体，它是由地中海诺卡氏菌经液体发酵提取纯化而制得，在发酵中的培养基中，硝酸钾对地中海诺卡氏菌生物合成利福霉素SV有刺激作用。培养基中加入定量的硝酸钾有利于提高利福霉素SV的产量。过去我厂50m^3发酵罐培养基配方中硝酸钾的浓度是6g／100ml。在生产中发现120小时以后出现了利福霉素SV的发酵单位增长缓慢甚至下降的情况。     

利福霉素产生菌发酵培养基的研究

本文考查了各种无机、有机氮源和黄豆饼粉酶解液对地中海诺卡氏菌(Nocardiamediterranei)C_(?)-8菌株生物合成利福霉素SV的影响。结果以蛋白胨、硝酸钾的效果为最佳。通过均匀设计的实验,获得了最佳发酵培养基的组成,使利福霉素SV的产量提高30%.     

利福霉素SV发酵工艺优化的研究

本文通过对影响利福霉素SV发酵因素一温度、溶氧和补料方式的研究，得出结论：在控制培养温度28．5℃、溶氧25％以上的条件下，采用流加方式补料工艺，利福霉素SV的发酵效价较原工艺有明显提高，此工艺已在20T发酵罐上进行工业化生产，发酵效价比原生产工艺有较大提高。     

利福霉素和利福平

1957年意大利米兰的莱佩蒂研究所Sensi等氏在链丝菌属Streptomyces Me-ditterranei发酵的培养基肉汤中发现一组天然抗菌素(利福霉素Rifamycin),其中利福霉素B活性最强,以后用人工方法改变其化学结构,先后获得O、S、SV三种衍化物,利福霉素S和SV的制菌力比利福霉素B和O强,而利福霉素SV的毒性又比利福霉素S小,故利福霉素SV在1962年就开始应用于临床。1962-1964年中已有很多学者报告了关于利福霉素实验研究和临床研究的结果,1965年Bergamin和Fowst两氏系统地报告了它们的化学结构,试管内的活性,药理及临床应用价值。利福霉素SV在试管内能抑制革兰氏阳性菌和抗酸菌的生长,尤其对结核菌和麻风杆菌显示有极强的制菌力,但口服疗效很不理想。1966年Maggi等氏又从几百个半合成的利福霉素衍化物中找到了利福平,它口服吸收很好,治疗结核病相当理想。     

利福霉素B发酵放大I．从摇瓶到15L发酵罐的发酵放大

研究了溶氧和剪切力对地中海拟分枝酸菌XC－925发酵产生利福霉素B的影响，并对利福霉素B从摇瓶到15L发酵罐的发酵放大及15L发酵罐流加补料发酵进行了研究。利用摇瓶研究结果表明地中海拟分枝酸菌XC－925发酵产生利福霉素B时对溶氧要求较高，而对剪切力不太敏感。以溶氧为依据，在15L发酵罐间歇发酵过程中，控制溶氧不低于25％，利福霉素B的发酵效价可达到1000u/ml左右，发酵周期（6d）较摇瓶发酵缩短了1d。15L发酵罐如采用流加补料发酵工艺，利福霉素B的发酵效价还会有较大幅度提高。     

无机氮对利福霉素B生物合成的影响

用于生物合成过程培养基的氮的形式,对生物合成抗生素影响很大。有机氮和无机氮对微生物的生长和抗生素的大量合成作用极大。无机氮在培养基中的形式,取决于产生抗生素的微生物特性。所以,铵氮用于链霉素、庆大霉素生产菌,氧化形氮用于albo·mycin和新生霉素生产菌,而无机氮源对林可霉素生产菌则起抑制作用。利福霉素B通常使用的无机氮源为硫酸铵。本文研究各种形式的无机氮源对利福霉素B生物合成的影响。利福霉素B生产菌为Nocardia medite-rranei1536菌株。实验培养基用豆粉作有机氮     

利福霉素B发酵放大Ⅰ.从摇瓶到15L发酵罐的发酵放大

研究了溶氧和剪切力对地中海拟分枝酸菌XC-925发酵产生利福霉素B的影响,并对利福霉素B从摇瓶到15L发酵罐的发酵放大及15L发酵罐流加补料发酵进行了研究.利用摇瓶研究结果表明地中海拟分枝酸菌XC-925发酵产生利福霉素B时对溶氧要求较高,而对剪切力不太敏感.以溶氧为依据,在15L发酵罐间歇发酵过程中,控制溶氧不低于25%,利福霉素B的发酵效价可达到10000u/ml左右,发酵周期(6d)较摇瓶发酵缩短了1d.15L发酵罐如采用流加补料发酵工艺,利福霉素B的发酵效价还会有较大幅度提高.     

利福霉素SV生物合成的代谢调节的研究

利福霉素作为一类抗生素,由地中海链霉菌(Streptomyces mediterranei)(现在称为地中海诺卡氏菌(Nocardia mediterranei)产生,它首先在1959年为Sensi等报道。有关利福霉素的生产、生物合成和发酵方面的综述已经发表。我们对于利福霉素SV的研究工作几年前就开始,主要集中在它的生物合成的调节机制方面。本文主要侧重报道了近来的进展。一、硝酸盐和无机磷的调节影响 (一)硝酸盐的影响在丰富培养基中,硝酸盐明显促进地中海诺卡氏菌NG12-4产生利福霉素SV(增加     

地中海诺卡氏菌发酵培养末期利福霉素SV失活原因初探

利福霉素SV(Rifamycin SV)具有抗革兰氏阳性菌及分枝杆菌活性,又是合成利福平的中间体,有广泛的应用价值。但地中海诺卡氏菌在发酵培养末期,发酵液突然起泡,由棕黄色转变为紫色,发酵液效价大幅降低,因此生产中要求严格控制放罐时     

利福霉素B发酵工艺研究

研究温度、溶氧、巴比妥、磷酸盐及补料方式对利福霉素B发酵的影响。结果表明在控制培养温度27℃，溶氧25％以上的条件下，采用流加补料工艺，利福霉素B的发酵效价较原工艺有明显提高，此工艺已在60m^3发酵罐中进行工业化生产，发酵效价比朱生产工艺提高了一倍以上。     

The interaction of rifamycin SV with hepatic transport of taurocholic acid in the isolated perfused rat liver

Summary The effect of rifamycin SV on hepatic transport of taurocholic acid was investigated using isolated perfused rat liver technique. In all experiments, the perfused liver was maintained at taurocholic acid steady state by infusing constant amount of taurocholic acid.Infusion of rifamycin SV at various rates decreased biliary secretion of bile acids in a dose-dependent manner. Replacement of rifamycin SV by perfusion medium reversed this effect.To determine the site of action of rifamycin SV, kinetic experiments with ¹⁴C-taurocholic acid were undertaken. Rifamycin SV elevated the half-life of the medium disappearance of ¹⁴C-taurocholic acid. Furthermore, the antibiotic delayed the biliary appearance of ¹⁴C-taurocholic acid.The analysis of the results gave indications that the antibiotic interferred with hepatic uptake as well as biliary secretion of taurocholic acid.Part of this publication was presented in the 18. Frühjahrstagung der Deutschen Pharmakologischen Gesellschaft (1977)     

含利福霉素钠注射液方案治疗肺结核的有效性和安全性评价

目的 :评价含利福霉素钠注射液 (SV)方案治疗肺结核的疗效和安全性。方法 :按随机配对法将44例肺结核患者分为利福霉素钠组 2 1例和常规治疗组 2 3例。化疗方案 :治疗组 2 1例采用 2HZE +SV 7HR方案治疗 ,对照组采用 2HRZE 7HR方案治疗。结果 :疗程结束时 ,治疗组痰菌转阴率 85 .7% ,病灶吸收好转率 90 .5 % ,对照组痰菌阴转率60 .9% ,病灶吸收好转率 60 .9% ,两组比较有统计学意义 (P <0 .0 5 )。结论 :含利福霉素钠注射液方案治疗肺结核有助于痰菌转阴和病灶吸收 ,疗效满意     

The effect of rifamycin SV on the wound-healing process.

The influence of rifamycin SV on the healing process of a wound was studied in animal experiments. Measurement of the degree of cicatrization, determination of the free hydroxyproline in serum, and histological findings helped to demonstrate that local application of rifamycin SV leads to an increased fibrinous conglutination of the lips of the wound at an early phase of the healing process and the subsequent formation of fibres in the regenerative tissue is not impaired.     

Oxygen radical damage to DNA by rifamycin SV and copper ions

The hydroquinone moiety of the antibiotic rifamycin SV reacts with molecular oxygen to form reduced oxygen intermediates such as superoxide (O2-.) and hydrogen peroxide (H2O2). The antibiotic semiquinone is also formed. Rifamycin SV in the presence of iron and copper salts can lead to the formation of the highly reactive hydroxyl radical (OH) which degrades the sugar deoxyribose. This damage is substantially inhibited by the enzyme catalase and scavengers of the hydroxyl radical such as formate, mannitol and thiourea. When linear duplex DNA is substituted for deoxyribose only rifamycin SV and copper ions substantially degrade DNA with release from the DNA molecule of thiobarbituric acid-reactive products. Damage to DNA by rifamycin and copper ions is significantly inhibited by catalase but poorly inhibited by scavengers of the hydroxyl radical consistent with a site-specific radical reaction of the DNA molecule. Several biological properties of rifamycin SV are known to resemble those of the metal chelating agent 1,10-phenanthroline. Here, we show that similarities extend to an unusual chemical property whereby thiobarbituric acid-reactive material is released from DNA in the presence of a copper salt.     

Rifamycins as inhibitors of collagenase activity: Their possible pharmacological role in collagen degradative diseases

The interaction of commercial rifamycin SV, rifamycin B, rifampicin and some other semi-synthetic analogous with collagenase in vitro was studied by using the fluorogenic substrate Mca-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH₂. Increased fluorescence, due to the removal of the NH₂-terminal dinitrophenyl group, after cleavage of the probe by collagenase was monitored and related to the enzyme activity. The peptide was an efficient substrate for collagenase with a K_m of 0.83 µM at 20°C in the presence of 10 µM Ca^{2 +}, pH= 7.5. In the same conditions, in the presence of rifamycin SV, rifampicin and rifamycin B or their semi-synthetic analogues AM₄₁, MC₁₁ and MC₃₀, a marked inhibition of the enzyme activity was observed and an IC₅₀ ranging from 13.1 to 20.7 µM was calculated. The inhibitory effect was reversible as demonstrated by restoration of enzyme activity by dialysis. These results may support the hypothesis that drugs based upon inhibitors of collagenase activity will provide a therapeutical tool for the underlying pathological destruction of extracellular matrix observed for instance in rheumatoid arthritis as reported by several authors.     

Electrochemical behavior and differential pulse polarographic determination of rifampicin in the pharmaceutical preparations

Differential pulse polarographic (DPP) analytical procedure for the rifampicin antibiotic, which can be applied to monitor its synthetic process from the starting antibiotic of rifamycin B or rifamycin SV, has been developed based on the electrochemical reduction of an azomethine group. Rifampicin exhibited a cathodic peak due to the azomethine group in the side chain of 3-[(4-methyl-1-piperazinyl)imino]methyl moiety and another cathodic peak due to the carbonyl group in rifamycin SV by DPP The experimental peak potential shift of an azomethine reduction was -73 mV/pH in the pH range between 3.0 and 7.5, agreeing with involvement of 4 e- and 5 H+ in its reduction. By the cyclic voltammetric(CV) studies, the azomethine and the carbonyl reductions in rifampicin were processed irreversibly on the mercury electrode. The plot of peak currents vs. concentrations of rifampicin ranging 1.0 x 10(-7) M tp approximately 1.0 x 10(-5) M yielded a straight line with a correlation coefficient of 0.9996. The detection limit was 1.0 x 10(-8) M with a modulation amplitude of 50 mV. DPP has been successfully applied for the determination of rifampicin in the pharmaceutical preparations.     

Pharmacokinetics and tissue distribution of rifametane, a new 3-azinomethyl-rifamycin derivative, in several animal species

Single and repeated dose experiments in mice, rats, dogs and monkeys are reported in this study to assess the pharmacokinetics and tissue distribution of rifametane, a new semi-synthetic rifamycin with the chemical formula 3-[(1-diethylaminoethylidene)azinomethyl]rifamycin SV (CAS 94168-98-6, SPA-S-565). All the kinetic tests were carried out in comparison with known rifamycin derivatives, as rifampicin (CAS 13292-46-1) or rifamycin SV (CAS 6998-60-3). Mice received single i.v. and oral administration of 10 mg/kg of rifametane or of rifampicin and serum samples were obtained up to 96 h after dosing. The two antibiotics showed similar peak of serum concentrations, but rifametane showed a longer half-life and higher AUC values. In an additional experiment, the tissue/serum ratio after the 10 mg/kg oral dose was lower than unity for lungs and kidneys, while the liver/serum ratio exceeded the unity at all sampling times. After 4 weeks of once weekly administration measurable serum and tissue concentrations were observed, and after twice weekly administration for the same time period some blood and tissue accumulation was seen. Rats were treated with a single intravenous injection of 20 mg/kg of rifametane or rifampicin and with single oral or i.m. administration of 60 mg/kg of rifametane or reference standards (rifampicin and rifamycin SV resp.), in two separate trials. The serum half-life of the test antibiotic after i.v. dose was 6 times longer than that of rifampicin and the serum concentrations of rifametane after oral and i.m. doses were higher and longer-lasting than those of the reference compounds. Repeated daily administrations of rifametane at three dose levels (3, 10, 30 mg/kg p.o.) for 4 weeks induced very high serum and liver concentrations. Dogs received a single oral dose of 1.25 mg/kg of rifametane or 2.5 mg/kg of rifampicin. The serum half-life of rifametane resulted 3 times longer than that of rifampicin. Remarkable serum and tissue concentrations were observed after 3-4 weeks of daily oral administration of rifametane at 3, 10, 30 mg/kg dose. Monkeys were given single oral or i.m. administration of 30 mg/kg of rifametane or reference standards (oral rifampicin and i.m. rifamycin SV). The serum concentrations after rifametane were higher and more sustained than those of reference compounds and the half-lives of the test antibiotic were about 2.5 (p.o.) to 6 times (i.m.) longer. The urine excretion of rifametane after a single intravenous dose in rats and a single oral dose in dogs was very low, while rifampicin had a little higher urine concentrations.     

3-N-Substituted aminomethyl derivatives of rifamycin SV. A convenient method of synthesis, cyclization of certain derivatives, and anticellular and antiviral activities of several derivatives.

A new synthesis of Mannich bases of rifamycin SV using the Borch2 procedure with rifaldehyde is described. This new synthesis offers two advantages over the previously published method. It provides a route to monoalkyl-aminomethylrifamycins (le-h) and to unsubstituted aminomethylrifamycins that were not accessible by the old procedure. The new method also offers a preparative route to Mannich bases 1a and 1b were needed in multigram quantities for biological testing. In addition, the cyclization of certain of the monoalkylaminomethylrifamycins to the novel N,15-didehydro-15-epi[methano(alkylimino)]rifamycin SV derivatives (2) is described. The anticellular and antiviral effects of representatives of both series of compounds against cultured mouse cells and murine oncornavirus are are discussed.     

Rifamycin SV MMX for the treatment of traveler’s diarrhea

Introduction: Rifamycin SV MMX®, a non-absorbable rifamycin antibiotic formulated using the multi-matrix system, was designed to exhibit its pharmacological action on the distal small intestine and colon. Its clinical efficacy and safety profile in the treatment of traveler’s diarrhea were evaluated in several clinical studies.

Areas covered: This review summarizes all available evidence regarding clinical trials of the efficacy and safety profile of rifamycin SV MMX for the treatment of traveler’s diarrhea.

Expert opinion: Rifamycin SV MMX demonstrated an excellent pharmacokinetic profile with decreased systemic toxicity similar to rifaximin. In phase II and phase III clinical trials, concerns have been raised regarding the medicine’s efficacy in terms of the time to last unformed stool and cure rate compared to current recommended antibiotics in the treatment of acute diarrhea caused by diarrheagenic Escherichia coli and invasive pathogens. The significance of the increase in MICs after the use of rifamycin SV MMX warrants further examination.