[Healing promoting effect of proamipide, a novel drug that increases gastric defense mechanisms, on acetic acid-induced gastric ulcers in the rat]

Rebamipide increases the amount of mucin-like substances on the conjunctiva and cornea in the N-acetylcysteine-treated in vivo model

PURPOSE

Rebamipide increases the amount of mucin-like substances in the stomach. We aimed to determine the effects of rebamipide on the amount of mucin-like substances in the conjunctiva and cornea of N-acetylcysteine-treated eyes. Furthermore, we attempted to evaluate the effects of rebamipide on the wound healing of N-acetylcysteine-treated eyes.

METHODS

The model was created by instilling 10% N-acetylcysteine solutions into rabbit eyes. Rebamipide was then applied on the day following the completion of N-acetylcysteine treatment. The amount of mucin-like substances on the conjunctiva and cornea was measured using the Alcian-blue binding method. The degree of damage was evaluated using scores based on the areas and densities of the cornea and conjunctival after staining using a rose Bengal solution under blind conditions.

RESULTS

Rebamipide increased the level of mucin-like substances on the conjunctiva of N-acetylcysteine-treated eyes when instilled at concentrations of 0.3% or higher, and 1% rebamipide increased the amount of mucin-like substances covering the cornea. Moreover, 1% rebamipide improved the rose Bengal scores of the cornea and conjunctiva in N-acetylcysteine-treated eyes.

CONCLUSIONS

Rebamipide increased mucin-like substances on the cornea and conjunctiva of N-acetylcysteine-treated eyes. In accordance with the mucin-increasing effects, rebamipide improved the rose Bengal scores for the cornea and conjunctiva of N-acetylcysteine-treated eyes. However, the relevance of these findings to dry eyes is unclear because it is not known whether the change in mucus expression in the N-acetylcysteine model is similar to what occurs in aqueous tear deficiency. Consequently, it may be worth trying on an animal model of keratoconjunctivitis sicca.

Efficacy of rebamipide as adjunctive therapy in the treatment of recurrent oral aphthous ulcers in patients with Behçet's disease: a randomised, double-blind, placebo-controlled study

BACKGROUND

Behçet's disease (BD) is a recurrent inflammatory disease involving chronic recurrent oral aphthous ulcers (aphthae), uveitis, skin lesions and genital ulcers. We prospectively investigated the efficacy of rebamipide, a gastroprotective drug, against oral aphthous ulcers in BD patients.

METHODS

In a multicentre, double-blind, placebo-controlled study, 35 patients with BD, having as the main symptom oral aphthosis, were randomised to receive rebamipide 300 mg/day or placebo for 12 to 24 weeks between August 1994 and December 1996. Oral aphthosis must have occurred within 4 weeks prior to enrolment and must have been visible for at least 7 days during that time. Oral aphthae count and pain scores were recorded daily in a diary by the patients themselves. Monthly aphthae count and pain scores were defined as the sum of aphthae count and pain scores for a month, respectively. Investigators rated the global improvement in aphthae count and pain using a 6-point scale. The rate of change in monthly aphthae count and pain scores in the first 3 and last 3 months of treatment were assessed in patients with more severe symptoms whose aphthae count and pain score were >28 at baseline (trial entry).

RESULTS

The rate of moderate or marked improvement in aphthae count and pain was 36% (5 of 14 subjects) in the placebo group and 65% (11 of 17 subjects) in the rebamipide group. During months 2 to 6 of treatment, aphthae count tended to increase and reached a peak at month 4 in the placebo group but decreased in the rebamipide group. Pain score decreased to the same extent in both groups for the first 3 months of treatment; however, in the fourth to sixth months of treatment, the pain score tended to increase in the placebo group but decreased in the rebamipide group. In patients with a monthly aphthae pain score >28 at baseline, pain and count scores decreased throughout the 6 months of rebamipide treatment but increased during the last 3 months of treatment in the placebo group (p < 0.01 for the between-group comparisons).

CONCLUSIONS

Rebamipide is well tolerated and improves the aphthae count and pain score in BD patients. It may therefore be useful in the treatment and prevention of frequently recurrent oral aphthous ulcers (not restricted to BD). Administration of rebamipide is not cumbersome, and it does not cause any discomfort, which corticosteroid ointments for example may do; furthermore, there are no specific adverse drug reactions. Rebamipide is therefore recommended as a long-term treatment for recurrent oral aphthous ulcers.

Bioequivalence of Rebamipide Granules and Tablets in Healthy Adult Male Volunteers

OBJECTIVE

Rebamipide tablets, which are used in the treatment of patients with gastric ulcers or gastritis, can be difficult to administer in subjects with reduced swallowing ability or impaired swallowing. The granule formulation may be more easily administered in these patients. The bioequivalence between rebamipide granules (20%/0.5g) and tablets (100mg) was determined in healthy male adult volunteers, in accordance with the Partially Revised Guidelines for Bioequivalence Studies of Generic Products.

STUDY DESIGN

In a randomised, nonblind, crossover design, 28 individuals were allocated into two groups of 14 to receive either rebamipide granules or rebamipide tablets. Each individual, under fasting conditions, was administered a single oral dose of rebamipide 100mg followed by a 7-day washout period. Individuals then received a single oral dose of the other rebamipide formulation. Blood samples were collected at 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12 and 24 hours. Plasma rebamipide concentrations were measured by validated high-performance liquid chromatography with tandem mass spectrometry.

RESULTS

The plasma concentration-time profiles and pharmacokinetic parameters of rebamipide after administration of the granule formulation were similar to those of the tablet in 27 healthy male volunteers. Following administration of the granule formulation, the area under the plasma concentration-time curve from time 0-24 hours (AUC(24h)) was 912.82 mug/L . h, the maximum plasma concentration (C(max)) was 241.82 mug/L, time to maximum plasma concentration (t(max)) was 2.5 hours, and plasma elimination half-life (t((1/2))) was 1.97 hours. Corresponding values for the tablet formulation were 873.55 microg/L . h, 216.19 mug/L, 2.4 hours, and 1.94 hours. The difference in mean log values was 1.01 for AUC(24h) and 1.09 for C(max) after granule and tablet administration. The 90% confidence interval of this difference in mean log value was 0.93-1.10 for AUC(24h), and 0.97-1.21 for C(max). This satisfies the criteria for bioequivalence in the guidelines [within log (0.8) to log (1.25)].

CONCLUSIONS

Rebamipide granules (20%/0.5g) and tablet (100mg) were bioequivalent. Rebamipide granules may therefore be a more practical treatment option in patients with gastric ulcers or gastritis who have difficulty swallowing tablets.

Positive effect of rebamipide on gastric permeability in mice after eradication of Helicobacter felis

BACKGROUND

Despite Helicobacter pylori eradication, gastric inflammation persists for months or years. Preliminary results have indicated that an increase in gastric permeability could be one reason. Our aim was to evaluate the effect of a mucosal protective drug, rebamipide, on gastric permeability in a model of H. felis-infected mice.

METHODS

Thirty-three C57/BL6 mice were inoculated with H. felis, and seven controls were kept non-inoculated. After 2 months 20 infected mice were treated with omeprazole, amoxicillin, and clarithromycin for 1 week and then for 4 weeks with either rebamipide (n = 9) or placebo (n = 11). The 13 remaining mice were kept untreated. After cessation of treatment, a fragment of antrum obtained from each mouse was mounted in a small Ussing chamber to study the electric resistance of the tissue (R) and antral permeability.

RESULTS

No modification of the paracellular permeability (R, JNa, JMan) was observed in either group. However, the transcellular permeability to horseradish peroxidase (HRP) was significantly increased in H. felis-infected non-treated mice (1131 +/- 463, 948 +/- 339, and 182 +/- 312 ng/h x cm2) as compared with non-infected controls (469 +/- 262, 458 +/- 261, and 10 +/- 6 ng/ h x cm2, for J3H-HRP, JD, and JHRPi, respectively) (P < 0.003). Eradication of the bacteria by antibiotics without subsequent treatment with rebamipide led to a non-significant decrease in the HRP fluxes. However, when rebamipide was used after the antibiotic treatment, a significant (P < 0.01) decrease in HRP fluxes as compared with non-treated mice was observed.

CONCLUSIONS

These results confirm that gastric permeability to macromolecules remains increased despite H. felis eradication and show that rebamipide can facilitate the normalization of gastric permeability to macromolecules after bacterial eradication.