In Vitro and In Vivo Trypanocidal Efficacy of Synthesized Nitrofurantoin Analogs.

African trypanosomes cause diseases in humans and livestock. Human African trypanosomiasis is caused by Trypanosoma brucei rhodesiense and T. b. gambiense. Animal trypanosomoses have major effects on livestock production and the economy in developing countries, with disease management depending mainly on chemotherapy. Moreover, only few drugs are available and these have adverse effects on patients, are costly, show poor accessibility, and parasites develop drug resistance to them. Therefore, novel trypanocidal drugs are urgently needed. Here, the effects of synthesized nitrofurantoin analogs were evaluated against six species/strains of animal and human trypanosomes, and the treatment efficacy of the selected compounds was assessed in vivo. Analogs 11 and 12, containing 11- and 12-carbon aliphatic chains, respectively, showed the highest trypanocidal activity (IC50 < 0.34 µM) and the lowest cytotoxicity (IC50 > 246.02 µM) in vitro. Structure-activity relationship analysis suggested that the trypanocidal activity and cytotoxicity were related to the number of carbons in the aliphatic chain and electronegativity. In vivo experiments, involving oral treatment with nitrofurantoin, showed partial efficacy, whereas the selected analogs showed no treatment efficacy. These results indicate that nitrofurantoin analogs with high hydrophilicity are required for in vivo assessment to determine if they are promising leads for developing trypanocidal drugs.

Single-step synthesis and in vitro anti-mycobacterial activity of novel nitrofurantoin analogues.

The emergence of drug-resistant tuberculosis (DR-TB) as well as the requirement for long, expensive and toxic drug regimens impede efforts to control and eliminate TB. Therefore, there's a need for effective and affordable anti-mycobacterial agents which can shorten the duration of therapy and are active against Mycobacterium tuberculosis (Mtb) in both active and latent phases. Nitrofurantoin (NFT) is a hypoxic agent with activity against a myriad of anaerobic pathogens and, like the first-line TB drug, rifampicin (RIF), kills non-replicating bacilli. However, the poor ability of NFT to cross host cell membranes and penetrate tissue means that it does not reach therapeutic concentrations. To improve TB efficacy of NFT, a series of NFT analogues was synthesized and evaluated in vitro for anti-mycobacterial activity against the laboratory strain, Mtb H37Rv, and for potential cytotoxicity using human embryonic kidney (HEK-293) and Chinese hamster ovarian (CHO) cells. The NFT analogues showed good safety profiles, enhanced anti-mycobacterial potency, improved lipophilicity, as well as reduced protein binding affinity. Analogue 9 which contains an eight carbon aliphatic chain was the most active, equipotent to isoniazid (INH), a major front-line agent, with MIC90 = 0.5 µM, 30-fold more potency than the parent drug, nitrofurantoin (MIC90 = 15 µM), and 100-fold more selective towards mycobacteria. Therefore, 9 was identified as a validated hit for further investigation in the urgent search for new, safe and affordable TB drugs.

Antibacterial organophosphorus compounds: phosphoranilidohydrazones of 5-nitro-2-furaldehyde.

A series of phosphoranilidohydrazones of 5-nitro-2-furaldehyde was synthesized and evaluated for antibacterial activity. The series was prepared to examine the applicability of phosphoramidic hydrazones as carriers for the antibacterial nitrofuran moiety. Designed as analogues of nitrofurantoin, members of the series were chosen according to the Topliss approach to analogue design. The title compounds were devoid of gram-negative activity but possessed moderate antistaphylococcal activity. The most potent members of the series were equipotent with nitrofurantoin against Staphylococcus aureus. The relationship between structure and antistaphylococcal activity is discussed.

Prophylactic chemotherapy with fosfomycin trometamol versus placebo during transurethral prostatic resection.

A prospective randomized controlled double-blind study was performed on 61 patients undergoing transurethral resection of the prostate. The first group of 31 patients received 3 g fosfomycin trometamol p.o. each on the evening before and after the operation; the second group of 30 patients received a placebo. Urine samples were taken by catheter puncture 24 and 48 h postoperative. After removal of the catheter (day 5) the first midstream urine was collected for culture, and from that moment on all patients were treated with a nitrofurantoin derivative for two weeks. Although the same strict antiseptic measures were standard practice for both groups, the incidence of early postoperative urinary tract infections was significantly lower for the fosfomycin trometamol group (0/31 versus 6/30 in placebo recipients). None of the patients suffered from a major symptomatic or complicated infection. There were no side effects registered.

Comparative human bioavailability study of macrocrystalline nitrofurantoin and two prolonged-action hydroxymethylnitrofurantoin preparations.

This single-blind crossover study compared the human bioavailability of macrocrystalline nitrofurantoin (Furadantine MC) and two prolonged-action hydroxymethylnitrofurantoin formulations (Urfadyn PL, bid, and Uridurine, tid), based on plasma nitrofurantoin concentrations and urinary nitrofurantoin excretion. The drugs were administered to 16 healthy females for a single day according to the recommended daily dosages. For comparison, Furadantine MC was administered both at the qid dosage recommended by the manufacturer and at tid dosage. Pharmacokinetic parameters determined were maximum plasma concentration after first dose, minimum plasma concentration after first dose, area under the plasma concentration-time curve (AUC), cumulative renal excretion over 30 hours (ARE), overall renal clearance, total body clearance, and bioavailability relative to Furadantine MC qid, based on plasma AUC (F) and ARE (Fren). F for Furadantine MC 100 mg tid was 108 +/- 25 percent (mean +/- SD); for Uridurine 100 mg tid and Urfadyn PL 100 mg bid, F equalled 86 +/- 33 percent and 53 +/- 20 percent (p less than 0.05), respectively. A similar relationship was observed between Fren for Furadantine MC 100 mg qid and the respective Fren of Furadantine MC 100 mg tid, Uridurine 100 mg tid, and Urfadyn PL 100 mg bid. No significant difference was found between the respective F and Fren of each of the drugs studied. Although bioavailability was comparable for Furadantine MC tid and qid, the single-day design of these studies precludes inferring that these dosage schedules are therapeutically equivalent. However, the significantly lower relative bioavailabilities for the prolonged-action hydroxymethylnitrofurantoin formulations suggest that Urfadyn PL 100 mg bid and Uridurine 100 mg tid are not pharmacokinetically equivalent to Furadantine MC.

Hepatic injury associated with the use of nitrofurans: a clinicopathological study of 52 reported cases.

Fifty cases of nitrofurantoin-associated hepatic injury and two cases of nifurtoinol (hydroxymethylnitrofurantoin)-associated hepatic injury reported to the Netherlands Centre for Monitoring of Adverse Reactions to Drugs were analyzed in detail. In 38 cases, a causal relationship was considered likely [i.e., "highly probable" (n = 4), "probable" (n = 23) or "possible" (n = 11)]. In 25 cases, hepatic injury was of the acute type whereas 13 cases presented a chronic type of reaction. Both types were more common in the elderly. Eighty per cent of the acute reactions appeared within the first 6 weeks of treatment and were sometimes accompanied by fever (28%), rash (12%) and eosinophilia (16%). Biochemically, the pattern was mainly hepatocellular (32%), whereas mixed cholestatic-hepatocellular (4%) and cholestatic (4%) patterns were uncommon. Although mild to moderate liver enzyme elevations (60%) were common, these were primarily symptomatic. The reaction was fatal in one "acute" and one "chronic" case. In the chronic cases, nuclear (82%) and smooth muscle (73%) antibodies and LE cells (50%) were frequently present. HLA typing showed no increase of the HLA B8 or HLA DRw3 haplotype. HLA DR2 (56%) and HLA DRw6 (56%) were more frequent than in controls (both 29%), but this was not statistically significant. Histology showed mainly necrosis, varying from spotty to massive, in the acute cases and a pattern consistent with chronic active hepatitis in the chronic cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Oxidative metabolites of 5-nitrofurans.

We synthesized the 4-hydroxy derivatives of nitrofurazone, furazolidone and nitrofurantoin. Then we dosed rats orally with these antibiotics and isolated the intensely yellow, polar metabolites from their urine. A comparison of the ultraviolet and nuclear magnetic resonance spectra of these metabolites with the corresponding synthetic derivatives confirmed that the metabolites are 4-hydroxynitrofurazone, 4-hydroxyfurazolidone and 4-hydroxynitrofurantoin.

Inhibition of platelet aggregation by 5-nitro-2-furaldehyde diacetate with observations on structure-activity relationships.

Nitrofurantoin [1-(5'-nitro-2'-furfurylideneamino)-2, 4-diketoimidazole] is a potent inhibitor of primary ADP-induced platelet aggregation. The nitro group on the furan ring and the specific arrangement of the two keto groups on the imidazole ring are the molecular characteristics of nitrofurantoin critical to its inhibitory effect. The present studies report that 5-nitro-2-furaldehyde diacetate is also a potent inhibitor of primary ADP-induced platelet aggregation. 5-Nitro-2-furaldehyde diproprionate, 5-nitro-2-furaldehyde dibutyrate, and 5-nitro-2-furfuryl acetate are essentially inactive. These results indicate that a diacetate moiety can replace the diketoimidazole moiety of nitrofurantoin and form a compound that fully retains the inhibitory effect upon primary ADP-induced platelet aggregation.