Prevacid
Determination of lansoprazole in biological fluids and pharmaceutical dosage by HPLC.

Avgerinos A, Karidas T, Potsides C, Axarlis S.

Military Pharmaceutical Laboratories, Athens, Greece.

A simple and rapid (extractionless) high-performance liquid chromatographic method with UV detection at 230 nm was developed for the determination of lansoprazole in biological fluids and pharmaceutical dosage. Niflumic acid was added as internal standard. The separation was performed at ambient temperature on a C18 Spherisorb column with acetonitrile + 0.1 M sodium acetate (40:60, v/v, pH 7) as mobile phase. The retention time was 5.2 min for niflumic acid and 6.7 min for lansoprazole. The detection limit was 20 ng/ml using a 100 microl loop. The method was successfully applied to a pharmacokinetic study of lansoprazole in humans.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9725501&dopt=Abstract lansoprazole Prevacid



Prevacid
Effect of proton-pump inhibitor therapy on diagnostic testing for Helicobacter pylori.

Laine L, Estrada R, Trujillo M, Knigge K, Fennerty MB.

University of Southern California School of Medicine, Los Angeles 90033, USA.

BACKGROUND: Proton-pump inhibitor therapy may cause false-negative results on Helicobacter pylori diagnostic testing. OBJECTIVE: To determine the frequency and duration of conversion of urea breath test results from positive to negative in patients given a proton-pump inhibitor. SETTING: Two urban university gastroenterology clinics. PATIENTS: Patients infected with H. pylori who had positive results on urea breath tests. INTERVENTION: Lansoprazole, 30 mg/d for 28 days. MEASUREMENTS: The urea breath test was repeated at 28 days. If the results were negative, testing was repeated 3, 7, 14, and 28 days after completion of therapy until the results reverted to positive. RESULTS: 31 (33%) of 93 patients in whom H. pylori was not eradicated had a negative breath test result while receiving lansoprazole. The proportions of patients whose breath test results were positive after completion of lansoprazole therapy were 91% (95% CI, 83% to 96%) at 3 days, 97% (CI, 90% to 99%) at 7 days, and 100% (CI, 96% to 100%) at 14 days. CONCLUSION: Patients should not receive proton-pump inhibitors for 2 weeks before receiving the urea breath test for H. pylori infection.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9758575&dopt=Abstract lansoprazole Prevacid



Prevacid
Effect of pirenzepine on gastric endocrine cell kinetics during lansoprazole administration.

Omura N, Kashiwagi H, Gang C, Omura K, Aoki T.

Department of Surgery, The Jikei University School of Medicine, Tokyo, Japan.

We studied the effect of pirenzepine on gastric secretion kinetics in rats in a hypochlorhydric state induced by lansoprazole, a proton pump inhibitor. Pirenzepine was administered intramuscularly at a dosage of 20 mg/kg twice daily; and lansorprazole, subcutaneously at 50 mg/kg once daily, both every day for 4 weeks. After the 4-week treatment, serum gastrin and plasma somatostatin levels were determined by radioimmunoassay. In addition, gastrin cells, somatostatin cells, and enterochromaffin-like cells were immunostained and counted. Serum gastrin levels were elevated, and gastrin and enterochromaffin-like cell numbers increased in the group on lansoprazole alone, compared with these values in the control group (which received distilled water). In the group on the lansoprazole and pirenzepine combination, serum gastrin levels decreased, and gastrin and enterochromaffin-like cell numbers were significantly decreased, compared with the respective variables in the group on lansoprazole alone, while the number of somatostatin cells increased in the group on the combination. Plasma somatostatin levels did not vary significantly in any group. It was thus demonstrated that pirenzepine corrects the abnormal gastric secretion kinetics resulting from treatment with lansoprazole alone, such as hypergastrinemia and gastrin and enterochromaffin-like cell hyperplasia.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9773926&dopt=Abstract lansoprazole Prevacid



Prevacid
The pharmacodynamics of lansoprazole administered via gastrostomy as intact, non-encapsulated granules.

Sharma VK, Ugheoke EA, Vasudeva R, Howden CW.

Department of Internal Medicine, University of South Carolina, Columbia, USA.

BACKGROUND: Because of its acid-labile nature, lansoprazole is usually administered as encapsulated enteric-coated granules. The gelatin capsule and acid-resistant coating of the granules have been considered essential for effective drug absorption and optimal bioavailability. Lansoprazole may attain effective plasma levels when given as non-encapsulated intact granules, but effects on intragastric acidity are unknown. AIM: To test the effectiveness of non-encapsulated. intact lansoprazole granules in suppressing intragastric acidity when administered through a gastrostomy. METHODS: Eight men, each with an established gastrostomy, underwent baseline 24 h intragastric pH monitoring while off any acid-suppressing medication. Via the gastrostomy, they then received 7 days of once-daily dosing with 30 mg lansoprazole as intact granules in 3 fl. oz. of orange juice. Intragastric pH monitoring was repeated on day 7. RESULTS: Mean intragastric pH pre-dosing was 1.96+/-0.5 (s.d.). This increased to 4.7+/-0.6 on day 7 (P < 0.0001). Median intragastric pH rose from 1.5 to 5.2 (P < 0.0001). Before lansoprazole, the proportions of time when intragastric pH was above 3, 4 and 5 were 23.2, 13.5 and 7.5%, respectively. Corresponding values after 7 days of lansoprazole were 81.1, 70.2 and 52.3% (P < 0.0001 for each comparison). CONCLUSION: Lansoprazole can effectively suppress intragastric acidity when given through a gastrostomy as intact, non-encapsulated granules in orange juice.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9845407&dopt=Abstract lansoprazole Prevacid



Prevacid
Effect of combined administration of lansoprazole and sofalcone on microvascular and connective tissue regeneration after ethanol-induced gastric mucosal damage.

Nakamura M, Akiba Y, Kishikawa H, Oda M, Ishii H.

Department of Internal Medicine, Tokyo Denryoku Hospital, Japan.

We undertook the present study to clarify the alteration of localization of basic fibroblast growth factor (bFGF), endothelial cells, and myofibroblasts in the healing of ethanol-induced gastric mucosal damage by the combined administration of lansoprazole and sofalcone. Wistar strain male rats were used. Ethanol 50% was given through orogastric intubation. Thirty minutes later, an aqueous solution of lansoprazole, sofalcone, a combination of lansoprazole and sofalcone, or physiologic saline was given orally. The stomach was removed and the localization of bFGF, myofibroblast, and endothelial cells was examined using monoclonal antibodies. Some rats were pretreated with indomethacin to rule out the effect of endogenous prostaglandin. The combined administration of lansoprazole and sofalcone brought about increased concentrations and immunoreactive areas of bFGF and a greater number of endothelial cells, compared with the ethanol-alone treatment. The number of myofibroblasts increased more significantly in the group treated with a combination of agents than in that treated with ethanol alone, ethanol plus sofalcone, or ethanol plus lansoprazole. Indomethacin pretreatment partly abolished the effects of single and combined administration of these agents. In conclusion, the mixed administration of lansoprazole and sofalcone accelerated the microvascular and connective tissue regeneration during the healing of ethanol-induced gastric mucosal damage.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9872517&dopt=Abstract lansoprazole Prevacid