Highly sensitive determination of 2-hydroxy-N-(3-[m-(1-piperidinylmethyl) phenoxy]propyl)acetamide (desacetyl TZU-0460) in rat plasma by high-performance liquid chromatography

Determination of roxatidine in human plasma by liquid chromatography/electrospray mass spectrometry and application to a clinical pharmacokinetic study

A rapid and sensitive liquid chromatography/mass spectrometry (LC/MS) method was developed and validated for the determination of roxatidine in human plasma. Roxatidine was extracted by single liquid-liquid extraction with tert-butyl methyl ether, and the chromatographic separation was performed on a C8 column. The total analytical run time was relatively short (5 min), and the limit of assay quantification was 2 ng/mL using 0.1 mL of human plasma. Roxatidine and the internal standard, propranolol, were monitored in selected ion monitoring (SIM) mode at m/z 307.3 and 260.3, respectively. The standard curve was linear over a concentration range from 2-500 ng/mL, and the correlation coefficients were >0.999. The mean intra- and inter-day assay accuracy ranged from 103.4-108.8% and 102.3-110.0%, respectively, and the mean intra- and inter-day precision was between 3.3-8.8% and 5.3-6.2%, respectively. The developed assay method was successfully applied to a pharmacokinetic study in human volunteers after oral administration of roxatidine acetate hydrochloride at a dose of 75 mg.

Roxatidine acetate. A review of its pharmacodynamic and pharmacokinetic properties, and its therapeutic potential in peptic ulcer disease and related disorders

Roxatidine acetate is a histamine H2-receptor antagonist which, after almost complete oral absorption (greater than 95%), is rapidly converted to its active metabolite, roxatidine, by esterases in the small intestine, plasma and liver. Roxatidine is a potent inhibitor of basal and stimulated gastric acid secretion in animals and humans and, like most other H2-receptor antagonists, has no anti-androgenic effects and does not interfere with the hepatic metabolism of other drugs. Large-scale trials have shown that roxatidine acetate 150mg per day is as effective as standard doses of cimetidine and ranitidine in the treatment of patients with duodenal or gastric ulcer, and that roxatidine acetate 75mg in the evening is likely to become a 'standard' regimen for the prevention of peptic ulcer recurrence. Preliminary data also suggest that roxatidine acetate may be useful in the treatment of reflux oesophagitis and stomal ulcer, and in the prevention of pulmonary acid aspiration. Roxatidine acetate is an H2-receptor antagonist which has been well tolerated in clinical trials. However, broader experience is required before definitive statements about tolerability relative to other H2-receptor antagonists can be made, and before the role of roxatidine acetate in the treatment of reflux oesophagitis and stomal ulcer, and the prophylaxis of acid aspiration pneumonitis, can be clearly defined.

Chromatography of histamine H1- and H2-receptor blockers in biosamples

This paper reviews thin-layer chromatographic, high-performance liquid chromatographic, gas chromatographic and gas chromatographic-mass spectrometric procedures for the identification and quantification of sixty histamine H1- and ten H2-receptor blockers in biosamples, published from 1984 to 1989. The biomedical importance of the published procedures and consequences for their choice, the sample preparation and the chromatography itself are discussed. The fundamental information about the biosample assayed, work-up, stationary and mobile phase, detection mode and sensitivity of each procedure is summarized in seven tables. They are arranged according to the chromatographic method and the category of histamine receptor blockers. Examples of typical chromatographic separations are presented in three figures.

Determination of roxatidine in human plasma, urine and milk by capillary gas chromatography using nitrogen-selective detection

An assay is described for the determination of roxatidine in human plasma, urine and milk by gas chromatography. Roxatidine is extracted from the basified matrix with dichloromethane and esterified with propionic anhydride prior to analysis of the extracts by capillary gas chromatography using a nitrogen-specific detector. Detection limits are 5 ng/ml for plasma and milk and 1 microgram/ml for urine, making the assay suitable for obtaining pharmacokinetic data from volunteer trials.