• Biomolecules & Therapeutics
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• v.8 no.4
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• pp.318-324
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• 2000

We have examined inhibitory erects on gasritis using omeprazole-cholestyramine resinate, which has been developed to increase the stability of omeprazole, the well-known proton pump inhibitor, in an acidic condition. To test the pharmacological action of this, we investigated the effect of omeprazole-cholestyramine resinate on indomethacin-induced gastritis in rats. Omeprazole was used as a reference drug. Orally administered omeprazole-cholestyramine resinate inhibited the indomethacin-induced gastritis in a dose-dependent manner. The inhibitory effect of omeprazole-cholestyramine resinate on the gastritis was similar to that of reference drug. In addition, rectal adminstration of the omeprazole-cholestyramine resinate inhibited the indomethacin-induced gastritis in a dose-dependent manner. The inhibitory effect of omeprazole-cholestyramine resinate was equipotent to reference drug. The basal gastric acid secretion was decreased when it was administered either orally or rectally. This inhibition of omfprazole-cholestyramine resinate was similar to that of omeprazole. These data suggest that omeprazole-cholestyramine resinate inhibit the gastritis in rats, and are comparable to omeprazole available in market.

• Journal of Pharmaceutical Investigation
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• v.27 no.1
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• pp.23-27
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• 1997

To investigate the effect of L-arginine as stabilizing agent for omeprazole, the degradation rate constant of omeprazole in aqueous solution was determined at 30, 40 and $50^{\circ}C$ with various ratios of L-arginine to omeprazole. The pH of omeprazole solutions was also determined. As the amount of L-arginine increased, the pH of omeprazole solution also increased, and the solution appeared to be more stable. The omeprazole in aqueous solution could be stabilized by more than 15:1 molar ratio of L-arginine to omeprazole. The stability of omeprazole in commercial products using L-arginine or sodium phosphate dibasic as stabilizing agent was investigated. Among the commercial products, the omeprazole product prepared with L-arginine (molar ratio of L-arginine to omeprazole, 20:1) was most stable.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.334-334
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• 1994

Omeprazole의 약동학적 Parameter는 tmax를 제외하고 두 군간에 유의한 (p<0.001) 차이론 보였다 : AUC의 평균치는 5-mephenytoin hydroxylation poor metabol izer에서 extensive metabol izer에 비해 약 6-7배 컸다. Omeprazole sulfone의 parameter는 omeprazole에서 관찰된 두 군간의 차이와 유사하였다. 그러나 5-hydroxyomeprazole의 경우에는 Cmax, AUC 등이 extensive metabolizer에서 더컸다. Omeprazole의 청소율은 S-mephenytoin hydroxylation 대사능(MR)과 유의한 상잔관계(rs=0.79, p<0.01)를 보였으며, omeprazole과 그 대사물(5-hydroxyomeprazole 및 omeprazole sulfone)의 반감기 또한 S-mephenytoin hydroxylation 대사능과 유의한 상관성을 보였다.

• Journal of Pharmaceutical Investigation
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• v.27 no.2
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• pp.133-137
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• 1997

Buccal absorption test of omeprazole in human was performed to determine the permeability of the drug molecule through oral mucous membrane. Oral mucosal adhesive tablets of omeprazole were prepared by compressing the omeprazole with a mixture of sodium alginate and hydroxypropylmethyl cellulose (HPMC) as bioadhesive polymers, magnesium oxide (MgO) as a stabilizer and sodium carboxymethyl cellulose (Na CMC) or cros-carmellose sodium (Ac-Di-Sol) as disintegrants. The bioadhesive force, stability in saliva and release characteristics of the tablets were evaluated. Omeprazole was absorbed about 23% in 15 min through human buccal mucous membrane. Furthermore, omeprazole was stable in saliva for more than 8 hrs when MgO was added to the tablet as the amount of 2.5 fold of omeprazole. The release rate of omeprazole was increased with increasing the amount of sodium alginate in the tablet. From these results, it is suggested that tablets composed of [omeprazole/HPMC/sodium alginate/MgO/Ac-Di-Sol and/or Na CMC (20/6/24/50/10) (mg/tablet)] are potential candidate for buccal drug delivery system.

• YAKHAK HOEJI
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• v.39 no.4
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• pp.401-410
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• 1995

Pharmacolinetic profiles of omeprazole enteric coated granules including Ramezole$^\circledR$, Losec$^\circledR$, omeprazole-Na and omeprazole-resin salt were studied using the crossover design in rats and rabbits. The absorption variance of the preparations at the altered pH condition of the gastrointestinal tract was also studied. After oral administration of four omeprazole enteric coated pellets (10mg/kg) with and without concomitant administration NaHCO$_{3}$ (5 mg/ml, 60 mM) in the rats, the differences of absorplion rate and extent were evaluated. In the NaHCO$_{3}$, administration group, the T$_{max}$ appeared to be 2~10 times shorter than water administration group, and the $C_{max}$ also increased to about 4 times, and the AUC increased to about 2.5 times. Pharmacokinetic parameters of four omeprazole enteric coated pellets in rats showed no statistical significance (ANOVA, P>0.05) in both groups. In the crossover study, the second dosed drug showed 4~5 times increased bioavailability than first dosed drug, which shows the strong carry-over effect of acid secretion of the first dosed drug. The differences of the pharmacokinetic parameters of the two test formulations (Losec$^\circledR$ and omeprazole-resin) showed no statistical significance.

• Journal of Pharmaceutical Investigation
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• v.23 no.4
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• pp.225-229
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• 1993

The stability of omeprazole in the aqueous solutions containing arginine or sodium phosphate dibasic(SPD) was examined at 30, 40 and $50^{\circ}C$. Arginine or anhydrous SPD was added to omeprazoie solution ($200{\mu}g/\;ml$ in distilled water) to yield $100{\mu}g/\;ml$ concentration of each. Then, the solution was kept at 30, 40 or $50^{\circ}C$ for 90 hrs. Aliquots of the solution were withdrawn at specified time intervals and assayed by HPLC for intact omeprazole. The remaining percentage-time curves revealed that omeprazole was degraded rapidly as funtions of time and temperature following pseudo first-order kinetics. The rate constant in the SPD solution was much higher than in the arginine solution. In other words. the degradation half-lives of omeprazole at $30^{\circ}C$, for example, was 148 and 76 hr in arginine and SPD solutions respectively. The initial pH of the solution containing $100{\mu}g/\;ml$ of arginine or SPD was 9.7 or 8.7, respectively. Since omeprazole is more stable as the pH of its solution becomes more alkaline, the longer half-life of omeprazole in arginine solution could be explained by the more alkaline characteristics of arginine than SPD in the solution. The activation energy necessary for the degradation reaction was almost identical in both solutions, indicating similar degradation mechanisms of omeprazole in the solutions. In conclusion, omprazole was more stable in the presence of arginine than of SPD.

• Korean Journal of Clinical Pharmacy
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• v.11 no.1
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• pp.13-18
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• 2001

Omeprazole is usually administered as encapsulated enteric-coated granules and enteric-coated tablets because of its acid-labile nature. For children and patients who can not swallow, it can be mixed with water or other liquid after a capsule is opened or a tablet is crushed. This study was performed to compare omeprazole liquid formulations of tablet and capsule Omeprazole 20 mg capsule containing enteric coated granules was opened and 20 mg entric-coated tablet was ground to be mixed with sodium bicarbonate solution, orange juice or water. Each liquid formulation was poured into dissolution tester, mixed with first solution (artificial gastric juice; pH 1.2) for two hours, then with second solution (artifical enteric juice; pH 6.8) for thirty minutes. pH was measured periodically for two and half hours. Samples were drawn periodically, mixed with lansoprazole as an internal standard, and injected to HPLC. As results, pH of sodium bicarbonate solution of omeprazole was significantly higher than that of orange juice or water in first solution (6.2-7.4 vs. 1.2, p<0.005). At 150 min, concentrations of omeprazole in three diluents with granules and in sodium bicarbonate solution of tablet powder sustained significantly higher than in other solution of tablet powder (p<0.001). In conclusion, enteric-coated granules from capsule with three diluents and powder from tablet in sodium bicarbonate solution was stable during dissolution test, which would be appropriate and recommended for patient who can not swallow solid preparations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3494-3499
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• 2009

The stability of omeprazole in the aqueous solutions containing loxoprofen or Sodium bicarbonate was examined at room temperature. Loxoprofen or Sodium bicarbonate (60 mg) was added to omeprazole (600 ${\mu}g$/ml) solution to check the stability profile. Then, the solution was kept at room temperature for 80 hours. The concentration was assayed at each concentration by stability-indicating High performance liquid chromatography (HPLC) method. Aliquots of the solution were withdrawn at specified time intervals and assayed by chromatographic analysis for intact omeprazole. The relation between omeprazole concentration and peak area was linear from 5 to 160 ${\mu}g$/ml. The analysis method was precise with relative standard deviation (% RSD) no greater than 3.05 %. The remaining percentage-time curves revealed that omeprazole was degraded rapidly as functions of time and temperature following pseudo first-order kinetics. In conclusion, the stability of omeprazole was significantly affected by liquid solutions mixed with alkalizer (Sodium carbonate) or the NSAIDs (loxoprofen).

• Korean Journal of Bronchoesophagology
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• v.19 no.1
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• pp.11-14
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• 2013

Gastro-esophageal reflux disease (GERD) is a recurrent, long-term gastrointestinal condition characterised by the abnormal reflux of stomach contents into the esophagus. Heartburn is the most dominant symptom, which can be life long and can considerably reduce quality of life. The main goals of treatment are to alleviate symptoms and prevent relapses, esophageal stricture and adenocarcinoma. This paper presents a review comparing the effectiveness of omeprazole with Nissen fundoplication surgery for the treatment of GERD. Nissen fundoplication is more effective in controlling heartburn symptoms, healing esophagitis and preventing relapses than omeprazole. Quality of life, in terms of productivity and ability to work, is difficult to assess in the omeprazole group and, as a result, a comparison of this aspect is limited. Although fundoplication is expensive in the short term, it is more cost-effective than omeprazole. Nurses need to be aware of the effectiveness of omeprazole and fundoplication to provide patients with accurate information, which assists patients in decision making regarding treatment options.

• Clinical and Experimental Pediatrics
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• v.59 no.5
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• pp.226-230
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• 2016

Purpose: Gastroesophageal reflux disease (GERD) occurs in pediatric patients when reflux of gastric contents presents with troublesome symptoms. The present study compared the effects of omeprazole and ranitidine for the treatment of symptomatic GERD in infants of 2-12 months. Methods: This study was a clinical randomized double-blind trial and parallel-group comparison of omeprazole and ranitidine performed at Children Training Hospital in Tabriz, Iran. Patients received a standard treatment for 2 weeks. After 2 weeks, the patients with persistent symptoms were enrolled in this randomized study. Results: We enrolled 76 patients in the present study and excluded 16 patients. Thirty patients each were included in group A (ranitidine) and in group B (omeprazole). GERD symptom score for groups A and B was $47.17{\pm}5.62$ and $51.93{\pm}5.42$, respectively, with a P value of 0.54, before the treatment and $2.47{\pm}0.58$ and $2.43{\pm}1.15$, respectively, after the treatment (P=0.98). No statistically significant differences were found between ranitidine and omeprazole in their efficacy for the treatment of GERD. Conclusion: The safety and efficacy of ranitidine and omeprazole have been demonstrated in infants. Both groups of infants showed a statistically significant decrease in the score of clinical variables after the treatment.