Molecular imprinted polymer-based potentiometric approach for the assay of the co-formulated tetracycline HCl, metronidazole and bismuth subcitrate in capsules and spiked human plasma

BACKGROUND

An anti-H-pylori co-formulated mixture of tetracycline HCl (TET), metronidazole (MET), and bismuth subcitrate (BSC) is recently available. Only two chromatographic and spectrophotometric methods are reported for determining those drugs simultaneously where the effect of impurities that could be present as well as the biological fluids matrix influence do not be taken into consideration. There is a need to develop an easy-to-use potentiometric technique for analysis of TET, MET, and BSC in their co-formulated capsules, in presence of some official impurities and in spiked human plasma.

RESULTS

Three carbon paste electrodes (CPEs) were fabricated for this purpose. Being a solid contact ion-selective electrode, CPE suffers from the creation of a water layer affecting its stability and reproducibility. Besides, it has a common problem in differentiation between two drugs carrying the same charge (positively charged TET and MET). Water layer formation was prevented through inserting polyaniline nanoparticles (≈10.0 nm diameter) between solid contact and ion-sensing membrane in the three proposed sensors. TET and MET interference was overcome by synthesizing a corresponding molecular imprinted polymer (MIP) for each drug. The synthesized MIPs were inserted in equivalent sensing membranes and characterized using several techniques. The suggested MIPs have a noticeable enhanced sensitivity in potentiometric determination. The obtained LODs were 5.88 × 10-8, 5.19 × 10-7, and 1.73 × 10-6 M for TET, MET and BSC proposed CPEs, respectively, with corresponding slopes of 57.37, 56.20, and -57.40 mV decade-1.

SIGNIFICANCE

The proposed potentiometric method makes the detection of the three cited drugs simple, fast, and feasible. This approach is the first for determining three drugs potentiometrically in one combined formulation. The obtained results were compared favorably with previously reported potentiometric methods.

Therapeutic Effects of Low-dose Bismuth Subcitrate on Symptoms and Health-related Quality of Life in Adult Patients with Irritable Bowel Syndrome: A Clinical Trial

Objective:

Irritable bowel syndrome (IBS) is a chronic functional disorder of the gastrointestinal tract that causes abdominal pain or discomfort and alters bowel with no organic abnormalities. Treatment options for IBS have increased in number in the past decade, and clinicians should not be limited to use only conventional treatments to cure it. This article is a placebo-controlled clinical trial to assess the therapeutic effects of low-dose bismuth subcitrate on symptoms and the health-related quality of life in adult patients with IBS.

Methods:

This clinical trial was done during July 2015 to January 2016 in Isfahan, Iran. For each of three subtypes (IBS-constipation dominant, IBS-diarrhea dominant [IBS-D], and IBS-mixed), we included patients with IBS aged 18–70 years, diagnosed according to the Rome III criteria. In this study, 129 eligible patients were enrolled, of which 119 continued on the protocol to the end of study. They were allocated in placebo group (Group A) and intervention group (Group B). The medication for Group B was mebeverine and bismuth subcitrate and for Group A was mebeverine and placebo of bismuth subcitrate. Initially, the patients of both groups completed IBS-related questionnaires (IBS-quality of life, IBS-severity scoring system), then given drugs for a 4-week period (1^st on-drug period). Then, both groups were given only mebeverine hydrochloride 200 mg capsule for another 4 weeks (off-drug period). At last, Group A and Group B were given medication (2^nd on-drug period), the same as 1^st on-drug period.

Findings:

With respect to quality of life, the trend of IBS-QOL score changed significantly during the study period in both the intervention and placebo groups; however, no significant differences were observed between the two groups (P < 0.005). In subgroups analysis, quality of life significantly improved in IBS-D during the study from the first measurement to the end of study (P = 0.004). The trends of changes in the severity of pain during the study between the intervention and control group were significantly different (P = 0.018).

Conclusion:

According to our study, IBS-D patients' symptoms improved significantly with bismuth therapy. We found that adding low-dose bismuth to mebeverine in nonresponsive IBS patients in conventional treatment could be helpful.

Quadruple therapy with moxifloxacin and bismuth for first-line treatment of Helicobacter pylori

AIM: To compare triple therapy vs quadruple therapy for 10 d as first-line treatment of Helicobacter pylori (H. pylori) infection.

METHODS: Consecutive H. pylori positive patients never treated in the past for this infection were randomly treated with triple therapy of pantoprazole (PAN) 20 mg bid, amoxicillin (AMO) 1 g bid and moxifloxacin (MOX) 400 mg bid for 10 d (PAM) or with quadruple therapy of PAN 20 mg bid, AMO 1 g bid, MOX 400 mg bid and bismuth subcitrate 240 mg bid for 10 d (PAMB). All patients were found positive at 13 C-Urea breath test (UBT) performed within ten days prior to the start of the study. A successful outcome was confirmed with an UBT performed 8 wk after the end of treatment. χ² analysis was used for statistical comparison. Per protocol (PP) and intention-to-treat (ITT) values were also calculated.

RESULTS: Fifty-seven patients were enrolled in the PAM group and 50 in the PAMB group. One patient in each group did not return for further assessment. Eradication was higher in the PAMB group (negative: 46 and positive: 3) vs the PAM group (negative: 44 and positive: 12). The H. pylori eradication rate was statistically significantly higher in the PAMB group vs the PAM group, both with the PP and ITT analyses (PP: PAMB 93.8%, PAM 78.5%, P < 0.02; ITT: PAMB 92%, PAM 77.1 %, P <0.03).

CONCLUSION: The addition of bismuth subcitrate can be considered a valuable adjuvant to triple therapy in those areas where H. pylori shows a high resistance to fluoroquinolones.