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Effective Helicobacter pylori (H. pylori) eradication is a major public health concern; however, eradication failure rates with the standard triple therapy remain high. We aimed to investigate the effectiveness and tolerability of ranitidine bismuth citrate (RBC) pretreatment before standard triple therapy for H. pylori eradication. A prospective, randomized, controlled, and open-label clinical trial was conducted from June to December 2019. H. pylori eradication rate, safety, and tolerability were compared between the standard treatment group (esomeprazole, amoxicillin, and clarithromycin for 7 days) and RBC pretreatment group (RBC for 2 weeks before standard triple therapy). This trial ended earlier than estimated owing to the N-nitrosodimethylamine concerns with ranitidine. Success rates of H. pylori eradication were 80.9% and 67.3% in the RBC pretreatment (n = 47) and standard treatment (n = 52) (p = 0.126) groups, respectively. Our trial was discontinued earlier than planned; however, a statistical significance would be achieved by expansion of our data (p = 0.031) if patient enrollment numbers reached those initially planned. Adverse event rates were comparable between groups (25.5% in the pretreatment group vs. 28.8% in the standard treatment group), without serious event. Tolerability was excellent in both groups, recorded as 97.9% and 100% in the pretreatment and standard treatment groups, respectively. Compared with the standard triple regimen, RBC pretreatment for 2 weeks may achieve higher H. pylori eradication rates, with excellent safety and tolerability. However, this study necessitates further validation as it was discontinued early owing to the N-nitrosodimethylamine issues of ranitidine.

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Sulfate-reducing bacteria have been implicated in inflammatory bowel diseases and ulcerative colitis in humans and there is an interest in inhibiting the growth of these sulfide-producing bacteria. This research explores the use of several chelators of bismuth to determine the most effective chelator to inhibit the growth of sulfate-reducing bacteria. For our studies, Desulfovibrio desulfuricans ATCC 27774 was grown with nitrate as the electron acceptor and chelated bismuth compounds were added to test for inhibition of growth. Varying levels of inhibition were attributed to bismuth chelated with subsalicylate or citrate but the most effective inhibition of growth by D. desulfuricans was with bismuth chelated by deferiprone, 3-hydroxy-1,2-dimethyl-4(1H)-pyridone. Growth of D. desulfuricans was inhibited by 10 µM bismuth as deferiprone:bismuth with either nitrate or sulfate respiration. Our studies indicate deferiprone:bismuth has bacteriostatic activity on D. desulfuricans because the inhibition can be reversed following exposure to 1 mM bismuth for 1 h at 32 °C. We suggest that deferiprone is an appropriate chelator for bismuth to control growth of sulfate-reducing bacteria because deferiprone is relatively nontoxic to animals, including humans, and has been used for many years to bind Fe(III) in the treatment of ß-thalassemia.

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BACKGROUND: Widespread use of antibiotics has resulted in increased rates of antibiotic resistance and decreased rates of Helicobacter pylori (H. pylori) eradication, leading to a search for newer therapeutic options. This study aimed to examine the efficacy, tolerability, and patient compliance of a first-line bismuth-containing 5-day concomitant quintuple therapy. MATERIALS AND METHODS: This prospective study included 144 eradication treatment naïve H. pylori positive patients with dyspeptic complaints. Patients received the following concomitant quintuple therapy for 5 days: bismuth subcitrate 300 mg q.i.d, omeprazole 20 mg b.i.d, clarithromycin 500 mg b.i.d., amoxicillin 1 g b.i.d., and metronidazole 500 mg t.i.d. Eradication was assessed with H. pylori stool antigen test or urea-breath test 6 weeks after the completion of therapy. RESULTS: Treatment compliance rate in this study was 97.2%. Intention to treat and per-protocol eradication rates were 134/144 (93.1%, 95% CI, 88.9-97.2) and 134/140 (95.7%, 95% CI, 92.2-98.6), respectively. Side effect was reported by 8.5% of the patients that attended follow-up visits, including epigastric pain (2.8%), nausea/vomiting (2.1%), diarrhea (1.4%), taste disturbance (1.4%), and fatigue (0.7%). CONCLUSIONS: Bismuth-containing, short course, quintuple concomitant therapy appears to be an effective and safe therapeutic option for the first-line H. pylori eradication, particularly in populations with high resistance.

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Galloyl- and caffeoylquinic acids are among the most important pharmacological active groups of natural compounds. This study describes a pre-step in isolation of some selected representatives of these groups from biological samples. A selective solid-phase extraction (SPE) method for these compounds may help assign classes and isomer designations within complex mixtures. Pure zirconium silicate and bismuth citrate powders (325 mesh) were employed as two new sorbents for optimized SPE of phenolic acids. These sorbents possess electrostatic interaction sites which accounts for additional interactions for carbon acid moieties as compared to hydrophilic and hydrophobic sorbents alone. Based on this principle, a selective SPE method for 1,3,4,5-tetragalloylquinic acid (an anti-HIV and anti-asthamatic agent) as a starting compound was developed and then deployed upon other phenolic acids with success. The recoveries and selectivities of both sorbents were compared to most commonly applied and commercially available sorbents by using high performance liquid chromatography. The nature of interaction between the carrier sorbent and the acidic target molecules was investigated by studying hydrophilic (silica), hydrophobic (C18), mixed-mode (ionic and hydrophobic: Oasis(®) MAX) and predominantly electrostatic (zirconium silicate) materials. The newly developed zirconium silicate and bismuth citrate stationary phases revealed promising results for the selective extraction of galloyl- and caffeoylquinic acids from natural sources. It was observed that zirconium silicate exhibited maximum recovery and selectivity for tetragalloylquinic acid (84%), chlorogenic acid (82%) and dicaffeoylquinic acid (94%) among all the tested sorbents.

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BACKGROUND: Helicobacter pylori infection is the main cause of gastritis, gastroduodenal ulcer disease, MALT lymphoma, and adenocarcinoma of the stomach. The reported prevalence of H. pylori in the adult population in Turkey is 67.6%-81.3%. A national meta-analysis showed that the average H. pylori eradication rate with proton pump inhibitor-based triple regimens in Turkey had decreased from 84% in 1997 to 55.3% in 2004, suggesting a need to evaluate alternative regimens. MATERIALS AND METHODS: The study was a prospective, single-center trial with a parallel group design. After the selection procedure, consecutive out-patients were assigned to one of six study groups using random sampling numbers. All patients received amoxicillin 1,000 mg b.i.d. and clarithromycin 500 mg b.i.d. along with ranitidine bismuth citrate 400 mg b.i.d., or omeprazole 20 mg b.i.d., or lansoprazole 30 mg b.i.d., or rabeprazole 20 mg b.i.d., or pantoprazole 40 mg b.i.d., or esomeprazole 40 mg b.i.d. for 14 days. RESULTS: When we look at the eradication rates of the treatment groups, only two groups (ranitidine bismuth citrate and rabeprazole groups) had eradication rates greater than 80%, both at intention to treat and per protocol analyses. The other four groups (omeprazole, lansoprazole, pantoprazole, and esomeprazole groups) showed statistically significant lower eradication rates both at intention to treat (between 57.6 and 66.7%) and per protocol (between 60.3 and 72.1%) analyses when compared with ranitidine bismuth citrate and rabeprazole groups (p<.05). CONCLUSION: Ranitidine bismuth citrate and/or rabeprazole based triple therapies must be preferred for the first-line treatment of H. pylori infection.

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Four bismuth complexes, (H2En)[Bi2(cit)2(H2O)4/3]·(H2O) x (1), (H2En)3[Bi2(cit)2Cl4]·(H2O) x (2), (HPy)2[Bi2(cit)2(H2O)8/5]·(H2O) x (3) and (H2En)[Bi2(cit)2](H2O) x (4) [cit = citrate4-; En = ethylenediamine; Py = pyridine] have been synthesized and crystallized. The crystal structures reveal that the basic building blocks in all of these complexes are bismuth citrate dimeric units which combine to form polymeric architectures. The embedded protonated ethylenediamine and pyridine moieties in the polymeric frameworks have been identified by X-ray crystallography and solid-state cross polarization/magic angle spinning (CP/MAS) 13C NMR. Based on the framework of complex 1, a structural model of a clinically used antiulcer drug, ranitidine bismuth citrate (RBC) was generated. The behavior of the protonated amine-bismuth citrate complexes in acidic aqueous solution has been studied by electrospray ionization-mass spectrometry (ESI-MS). ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available for this article at 10.1007/s11426-010-4113-x and is accessible for authorized users.

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Objective To systematically review the Helicobacter pylori eradication efficacy with ranitidine bismuth citrate(RBC) and two antibiotics,and to conduct a meta-analysis of randomized clinical trials comparing the efficacy of proton pump inhibitor(PPI)vs RBC with two antibiotics for 1 week.Methods Selection of studies:studies evaluating RBC plus two antibiotics were considered.For the meta-analysis,randomized controlled trials comparing PPI vs.RBC plus two antibiotics for 1 week were included.Data Source:RCTs were identified from CBM,handsearching,and personal contact with pharmaceutical companies.Inclusion criteria:data were extracted independently by two reviewers.The methodological quality of trials was assessed by the Jadad-scale.Statistics analysis was managed by using RevMan 4.2.Results Twelve randomized clinical trials including 1254 patients were included.The meta-analysis showed comparable efficacy with RBC and PPI (OR=1.30,95% CI:0.94～1.81,P=0.12).Conclusion The efficacy of RBC and PPI-based triple regimens were comparable.