[Helicobacter pylori resistance to metronidazole and clarythromicin: descriptive analysis 1997-2000]

Gastroretentive drug delivery systems for the treatment of Helicobacter pylori

Helicobacter pylori (H. pylori) is one of the most common pathogenic bacterial infections and is found in the stomachs of approximately half of the world's population. It is the primary known cause of gastritis, gastroduodenal ulcer disease and gastric cancer. However, combined drug therapy as the general treatment in the clinic, the rise of antibiotic-resistant bacteria, adverse reactions and poor patient compliance are major obstacles to the eradication of H. pylori. Oral site-specific drug delivery systems that could increase the longevity of the treatment agent at the target site might improve the therapeutic effect and avoid side effects. Gastroretentive drug delivery systems potentially prolong the gastric retention time and controlled/sustained release of a drug, thereby increasing the concentration of the drug at the application site, potentially improving its bioavailability and reducing the necessary dosage. Recommended gastroretentive drug delivery systems for enhancing local drug delivery include floating systems, bioadhesive systems and expandable systems. In this review, we summarize the important physiological parameters of the gastrointestinal tract that affect the gastric residence time. We then focus on various aspects useful in the development of gastroretentive drug delivery systems, including current trends and the progress of novel forms, especially with respect to their application for the treatment of H. pylori infections.

Ten-day sequential treatment for Helicobacter pylori eradication in clinical practice

BACKGROUND

Cure rates of Helicobacter pylori infection with standard triple therapy are disappointingly low. A very effective, new sequential treatment schedule has recently been described. However, all studies published to date were performed in Italy; it is mandatory to confirm these results in other settings.

AIM

To assess the cure rate and the acceptability of a new sequential treatment regimen through a pilot study.

METHODS

A hundred and thirty-nine patients (60% men, mean age 49.6 +/- 15.7 yr) were recruited from six centers. H. pylori status was assessed by histology, urease test or urea breath test. Sequential regime consisted of a 10-day treatment including a proton pump inhibitor (PPI) b.d. plus amoxicillin 1 g b.d. for the first 5 days, followed by a PPI b.d. clarithromycin 500 mg b.d. and metronidazole 500 mg b.d for the next 5 days. Eradication was determined 8 wk after the end of treatment by urea breath test or histology. Eradication rates were calculated both per protocol and by intention-to-treat.

RESULTS

Eradication was achieved in 117 out of 129 patients who returned for a follow-up test. The intention-to-treat eradication rate was thus 84.2% (95%CI: 77%-90%) and the per-protocol cure rate 90.7% (95%CI: 84%-95%). The treatment was well tolerated. Only 14 patients complained of mild side effects.

CONCLUSIONS

Sequential treatment seems highly effective for eradicating H. pylori.

Clinical trial evaluating amoxicillin and clarithromycin hydrogels (Chitosan-polyacrylic acid polyionic complex) for H. pylori eradication

AIM

It has been suggested that enhancement of amoxicillin or clarithromycin concentration at the gastric tissue may improve the anti-Helicobacter pylori effect of these drugs. This could be achieved by allowing the drug to remain longer in the stomach using dried hydrogels. Our aim was to evaluate the efficacy of an H. pylori eradication regimen including both amoxicillin and clarithromycin hydrogels.

DESIGN

prospective clinical trial.

PATIENTS

with peptic ulcer or functional dyspepsia.

INTERVENTION

7-day rabeprazole-amoxicillin-clarithromycin regimen. In addition, amoxicillin and clarithromycin hydrogels were administered twice daily during the 7 days. The polyionic complex hydrogel was prepared with Chitosan and polyacrylic acid.

OUTCOME

H. pylori eradication was defined as a negative C-urea breath test 8 weeks after completing therapy.

RESULTS

Forty patients were included. One patient did not return for follow-up. Ninety percent of the patients took all the medications correctly. Per-protocol and intention-to-treat eradication rates were 74% (95% CI=58%-86%) and 70% (55%-82%). Mild adverse effects were reported in 4 (10%) patients (diarrhea in 3, and nausea/heartburn in 1).

CONCLUSIONS

Although dried polyionic complexes could serve as suitable candidates for amoxicillin and clarithromycin site-specific delivery in the stomach, its addition does not increase the eradication efficacy of the generally prescribed proton pump inhibitor plus amoxicillin and clarithromycin regimen.