In vitro and in vivo evaluation of seven 50 mg and 100 mg nitrofurantoin tablets

Four 50 mg and three 100 mg marketed nitrofurantoin tablets were studied in 14 healthy male subjects. Urine was collected 1, 2, 3, 4, 6, 8, 12, and 23 h after each dose, and nitrofurantoin was assayed by HPLC. The in vitro dissolution of the tablets was determined using USP Apparatus 1 and 2, with 0.1 N hydrochloric acid and pH 7.2 buffer as the dissolution fluids. One of the 50 mg tablets was more rapidly and completely absorbed than the other six products. The incidence of side-effects for this product was as low or lower than the other products. It was determined that the use of the USP Apparatus 1, at 100 rev min-1, with sampling of the pH 7.2 fluid at 30 min, provided for the best overall relationship between the urinary excretion and in vitro dissolution.     

二阶导数光谱法测定尿中呋喃妥因浓度

本文采用有酸性条件下用乙酸乙酯萃取呋喃妥因后，通过二阶导数光谱法测定尿中呋喃妥因的浓度。该法定量信息为３７４￣３７７ｎｍ处的峰谷之间距离，最低检出浓度为１．５ｍｇ／Ｌ，回收率为９８％，相对标准差小于３％；本法与ＨＰＬＣ法进行了对照性研究。两法具有明显的相关性（ｒ＝０．９９９１）。本法可用于呋喃妥因药动学的研究。     

33 factorial design-based optimization of the formulation of nitrofurantoin microcapsules

A microcapsule form of nitrofurantoin was prepared by a simple coacervation method with carboxymethylcellulose and aluminium sulfate. 3³ factorial design was performed for three independent variables, namely, the particle size of the drug, the size of the microcapsules and the pH of the dissolution medium. The dissolution tests with the formulated microcapsules were carried out according to the United States Pharmacopeia XXII rotating basket method at pH 1.2, 5 and 7.5, which represent the pH of gastrointestinal fluids. Release data were examined kinetically and the ideal kinetic models were estimated and t _63.2 values obtained from RRSBW distribution were used in the factorial design experiment. The influence of the independent variables on the dissolution of nitrofurantoin microcapsules could be expressed as the pH of the dissolution medium > particle size of the microcapsule > particle size of nitrofurantoin. The other aim of this study was to evaluate microcapsule formulation in terms of the United States Pharmacopeia criteria with a minimum of experiments. Our findings suggest that dosage forms which comply with the pharmacopoeia criteria for dissolution can be prepared and selected by factorial design.     

Empirical treatment of lower urinary tract infections in the face of spreading multidrug resistance: in vitro study on the effectiveness of nitroxoline

The spread of antimicrobial resistance challenges the empirical treatment of urinary tract infections (UTIs). Among others, nitrofurantoin is recommended for first-line treatment, but acceptance among clinicians is limited due to chronic nitrofurantoin-induced lung toxicity and insufficient coverage of Enterobacteriaceae other than Escherichia coli. Nitroxoline appears to be an alternative to nitrofurantoin owing to its favourable safety profile, however data on its current in vitro susceptibility are sparse. In this study, susceptibility to nitroxoline was tested against 3012 urinary clinical isolates (including multidrug-resistant bacteria and Candida spp.) by disk diffusion test and/or broth microdilution. At least 91% of all Gram-negatives (n?=?2000), Gram-positives (n?=?403) and yeasts (n?=?132) had inhibition zone diameters for nitroxoline ≥18?mm. Except for Pseudomonas aeruginosa, nitroxoline MIC₉₀ values were ≤16?mg/L and were 2- to >16-fold lower compared with nitrofurantoin. In extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae and methicillin-resistant Staphylococcus aureus (MRSA), MIC₉₀ values of nitroxoline were two-fold higher compared with non-ESBL-producing enterobacteria and methicillin-susceptible S. aureus (MSSA). The in vitro efficacies of nitroxoline and nitrofurantoin against ATCC strains of E. coli, Enterococcus faecalis and Proteus mirabilis were compared by time–kill curves in Mueller–Hinton broth and artificial urine. Nitroxoline was non-inferior against E. coli, P. mirabilis and E. faecalis in artificial urine. In conclusion, nitroxoline showed a broad antimicrobial spectrum, with inhibition zone diameters and MICs of nitroxoline well below the EUCAST breakpoint for E. coli for most organisms, and thus may also be a target for therapy of uncomplicated UTIs.     

呋喃妥因肠溶片中邻苯二甲酸酯类物质的定性分析及定量检测

目的建立呋喃妥因肠溶片中邻苯二甲酸酯类物质定性分析及定量检测的方法。方法采用气质联用色谱法进行定性分析。采用高效液相色谱法对筛查出的5种邻苯二甲酸酯类物质进行定量检测,色谱柱为Phenomenex C18色谱柱(250mm×4.6mm,5μm),以乙腈-水(90∶10)为流动相,流速1.0mL·min-1,检测波长为224nm,柱温为30℃。结果对用气质联用色谱法筛查出的5种邻苯二甲酸酯类物质,建立了高效液相色谱法测定方法。DMP,DEP,DBP,DPP和BBP质量浓度在1²50μg·mL-1范围内线性关系良好,回收率在87%250μg·mL-1范围内线性关系良好,回收率在87%¹07%范围内。结论该法简便、快速、准确,可用于呋喃妥因肠溶片中邻苯二甲酸酯类化合物的定性分析及定量检测。     

呋喃妥因的合成

目的合成标题化合物，并进行工艺改进。方法以5-硝基呋喃醛二乙酯和盐酸氨基海因为原料缩合得到呋喃妥因。结果总收率为87．8％，所得产物经元素分析、紫外光谱、红外光谱、核磁共振谱及质谱等确证了结构。结‘论该合成工艺具有原料易得。操作简便．易于工业化生产等特点。     

Nitrofurantoin Neuropathy

Abstract: Four cases of severe peripheral neuropathy directly attributable to nitrofurantoin are reported. The neuropathy was not dose-related and not necessarily associated with abnormal renal function. Recovery was slow, and neither severity nor recovery was related to the total dose of the drug. The pathological changes seen on light microscopy and electron microscopy were those of acute, severe axonal degeneration. It is emphasised that nitrofurantoin is a neurotoxic drug and should not be prescribed to the elderly nor to anyone with impairment of renal function.     

胶体金试纸法研究及在硝基呋喃类代谢物应用

目的:通过对胶体金试纸条的研究,并用该方法对硝基呋喃类代谢物残留量中呋喃妥因代谢物(AHD)进行测定。方法:用胶体金试纸法测定牛奶中硝基呋喃类代谢物残留量中呋喃妥因,与ELISA法进行比较。结果:本方法的测定结果与ELISA法检测结果相符,总符合率达100%;另外,两种方法的测定结果经配对t检验,结果差异无显著性(P>0.05);回收率在85%～92%之间,相对标准偏差14.5%。结论:胶体金试纸条法的建立与研究,并在牛奶中硝基呋喃类代谢物呋喃妥因残留量的应用;具有快速、准确、省时、灵敏与简便的特点。     

二阶导数光谱法测定尿中呋喃妥因浓度

本文采用在酸性条件用乙酸乙酯萃取呋喃妥因后,通过二阶导数光谱法测定尿中呋喃妥因的浓度。该法定量信息为374～377nm处的峰谷之间距离,最低检出浓度为1.5mg/L,回收率为98％,变异系数小于3％,本法与HPLC法进行了对照性研究,两法具有明显的相关性(r=o.9991)。本法可用于呋喃妥因药动学的研究。     

Effects of exogenous factors on the cerebral glutathione in rodents

Since glutathione is thought to be involved in cerebral functions, changes in the glutathione level imply modulations of the neurotransmission in addition to all the known effects of GSH. It was investigated whether alterations of the cerebral glutathione can be induced by consumption of GSH, by inhibition or stimulation of the synthesis of GSH, or by an inhibition of the re-reduction of the oxidized glutathione. Aminophenazone, propyphenazone, acetaminophen, phenytoin, morphine and nitrofurantoin, known to deplete hepatic GSH, had no effects on cerebral GSH. Diethyl maleate (0.6 ml/kg) decreased the cerebral content of GSH and GSSG in adult rats as well as in fetuses. The depletion of the cerebral GSH caused by diethyl maleate treatment for 4 days was followed by an increase up to 125% and a subsequent return to the normal level after 1 week. In rats starved up to 71 h deficiency of exogenous amino acids caused only a minimal or no decrease in cerebral GSH. The specific inhibitor of the gamma-glutamylcysteine synthetase BSO only depleted GSH in the brain of young mice following the repeated s. c. administration of a high dose (890 mg/kg). After cobaltous chloride (20 mg/kg; twice a day for 2 or 4 days) the GSH level in the brain was unchanged. In vivo inhibition of the cerebral glutathione reductase was caused by ammonium metavanadate (12.5 mg/kg; three times a week for 6 weeks). Nitrofurantoin (150 mg/kg) had no effect. After lomustine (10 mg/kg) a minimal increase in glutathione reductase was found, but simultaneously also an increase in GSSG and of the ratio GSSG/total glutathione.