Objective To observe the diagnostic value of Omeprazole (Losec) test in gastro-esophageal reflux disease. Methods According to clinical manifestations and results of esophageal 24 h pH monitoring and gastro-esophageal endoscopy, 152 patients with reflux symptoms (123 GERD, 29 non-GERD) were randomly, double-blindly divided into group A (Omeprazole 20 mg/d for 1 week), group B(Omeprazole 40 mg/d for 2 weeks), and group C (placebo at the first week, Omeprazole 40 mg/d at the 2 nd week). Symptom score from heartburn, acid regurgitation, food regurgitation, and substernal pain, was recorded before and after taking Omeprazole or placebo. Results After taking Omeprazole 1 week, the symptom score decreasing from GERD patients of group A, B and C was 5.0?4.8、4.9?4.6、2.3?4.0 respectively, score decreasing 2 was the best critical value for GERD diagnosis. There was no difference between Omeprazole 20 mg/d and 40 mg/d for 1 week, the results showed that Omeprazole test (20 mg/d for 1 week) has the best diagnostic value for GERD, the diagnostic sensitivity was 82.5%, specificity was 40.1%, coincident rate was 76.7%. Conclusion Omeprazole test is reliable for GERD diagnosis.

PurposeTo study the pharmacokinetic characteristics of omeprazole in Chinese extensive and poor metabolizers.Methods The pharmacokinetics of omeprazole was studied in eighteen healthy volunteers. After a single oral dose of omeprazole capsule(40 mg), the plasma concentrations of omeprazole and its two metabolites, 5-hydroxyomeprazole and omeprazole sulfone, were determined with reversed HPLC method. The plasma concentration-time data were analyzed to estimate the pharmacokinetic parameters. Results Both plasma omeprazole concentration and the pharmacokinetic parameters exhibited marked interindividual variation. The metabolic ratio (MR= plasma omeprazole/5-hydroxyomeprazole) obtained 3.5 h after medication was used to distinguish between extensive and pcr)r metabolizers (EMs, PMs). The variances of AUC(0-12) caused by the two metabolizer phenotypes accounted for 75.4 % of the total interindividual variances. AUC(0-12) of omeprazole was (1 971.78 ±1 221.78)ng·h/ml in EMs( n=12) and (8 587.18±2 855.48) ng·h/ml in PMs (n = 6),respectively (P<0.01),and CL in EMs and PMs was estimated as (16.00±9.71) and (4.79±1.32) L/h (P<0.01). Accordingly,significantly lower level of plasma 5-hyclroxyomeprazole was found in PMs, revealing a slower hydroxylation rate compared with EMs. Conclusions The results suggest that individualized dose regimen of omeprazole, based on identification of metabolizer phenotype, can be of great benefit from the viewpoint of pharmacoeconomics.

This study is to investigate the effects of aqueous extract of Schisandra chinensis Baill (WWZ), kadsurin, schisandrin A, schisandrin B and schisandrol B on rat hepatic CYP3A. Rats received a daily gavage of aqueous extract of WWZ for different times. The livers were harvested after gavage and subjected to microsome preparation. Microsomal CYP3A activity was determined by measuring the amount of the metabolite of testosterone (6 beta-hydroxytestosterone) with HPLC. Aqueous extract of WWZ, kadsurin and schisandrin A were incubated with microsomes obtained from rat. Microsomal CYP3A activity was determined by HPLC. Primary hepatocytes were separated and extracted from rat, then were treated with aqueous extract of WWZ, schisandrin A, schisandrin B and schisandrol B. Then, the expression of CYP3A1 mRNA was analyzed by RT-PCR. As for the in vivo assay, aqueous extract of WWZ significantly inhibited the enzyme activity of CYP3A after 12 h gavage. The inhibitory effect was converted to inductive effect after 3-day gavage. Aqueous extract of WWZ could induce the enzyme activity of CYP3A after 6-day gavage. Aqueous extract of WWZ and kadsurin showed a dose-dependent inhibition of CYP3A (IC50 of 487.8 microg mL(-1) and 6.2 micromol L(-1), separately). In rat primary hepatocytes, aqueous extract of WWZ (2.5 mg mL(-1)), schisandrin A (0.1 micromol L(-1)), schisandrin B (0.1 micromol L(-1)) and schisandrol B (10 micromol L(-1)) increased significantly the expression of CYP3A1 mRNA by 23%, 55%, 42% and 27%, respectively. Aqueous extract of WWZ could show dual effect on the enzyme activity of CYP3A in rat in vivo. Meanwhile, kadsurin showed a dose-dependent inhibition of the enzyme activity of hepatic CYP3A in vitro. And schisandrin A, schisandrin B and schisandrol B showed significant inductive effect on the expression of rat CYP3A1 mRNA.

4 was found significantly higher in esomeprazole group than in rabeprazole group during first 4 hours (58.9% vs 32.1%), 24 hours on day 1 (73.7% vs 54.8%) and 24 hours on day 5 (84.2% vs 76.2%) (P 4 for at least 16 hours on day 1 and day 5 was higher in esomeprazole group than in rabeprazole group (day 1 63.9% vs 33.3%, day 5 88.9% vs 61.1%, P