Determination of metronidazole in a rat stomach by HPLC for obtaining basic data of the eradication therapy of Helicobacter pylori

[Formulation Studies and Application of Their Experimental Techniques to Drug Discoveries]

In my first experience as a researcher, I isolated and performed structural predictions of the novel compounds, cis- and trans-palythenic acids, from Noctiluca milialis. I then worked for a pharmaceutical company in a research laboratory of pharmaceutics. I examined an inclusion complex of cinnarizine with β-cyclodextrin, and found that the inclusion complex did not improve the oral bioavailability of cinnarizine. However, the bioavailability of the inclusion complex after its oral administration was improved by a competing agent. This was the first study to show the potential of a competing agent to improve bioavailability. I subsequently joined a laboratory performing drug discovery research and used experimental techniques from pre-formulation studies. A screening system of solubility for drug design and discovery was constructed to increase the solubilities of compounds synthesized in the laboratory. This screening system contributed to the discovery of a phosphodiesterase type 5 inhibitor with sufficient solubility. As a visiting lecturer at a university, I prepared amoxicillin intragastric buoyant sustained-release tablets for the eradication of Helicobacter pylori and applied cinnarizine as a competing agent. I established a laboratory of pharmaceutics at a university in Tochigi. To develop an enema with fluticasone propionate for ulcerative colitis, I investigated its physicochemical properties and methods to improve its solubility. After moving to another university in Kagawa, I developed a method to reduce the amount of drugs remaining on the surfaces of a pestle and mortar following the grinding of tablets, and new cleaning agents for an automatic dividing packaging machine were discovered.

Quantification of metronidazole in healthy subjects' feces using an LC-MS/MS method

A highly selective and sensitive liquid chromatography-tandem mass spectrometry (LC MS/MS) method was developed for the quantification of metronidazole (MTZ) in human feces. The analyte was recovered from feces after liquid-liquid extraction with ethyl acetate and separated on Waters Symmetry® C18 (100 × 4.6 mm, 5μm) column using 0.1% formic acid in water and acetonitrile (40:60, v/v) as the mobile phase. A stable-deuterated internal standard metronidazole-d4 (MTZ-d4) was used in the study. Mass analysis was performed on a triple quadrupole mass spectrometer in the positive electrospray ionization mode. A linear response function of MTZ was established in the concentration range of 0.50-250 ng/g, based on dry mass. The mean extraction recovery of MTZ (97.28%) and MTZ-d4 (96.76%) from spiked feces samples was consistent at higher as well as lower concentrations. Post-column infusion analysis showed no ion-suppression/enhancement effects and the mean IS-normalized matrix factor ranged from 0.986 to 1.013. Spiked feces samples stored at -20 and - 70°C for long-term stability were stable for at least 3 months, while extracted samples (dry and wet extracts) were stable up to 24 h. The method was applied to determine MTZ in feces of 12 healthy Indian subjects.

Advanced trends in controlling Helicobacter pylori infections using functional and therapeutically supplements in baby milk

Helicobacter pylori is a common human pathogen infecting about 30 % of children and 60 % of adults worldwide. It is responsible for diseases such as gastritis, peptic ulcer and gastric cancer. H. pylori treatment based on antibiotics with proton pump inhibitor, but therapy failure is shown to be higher than 20 % and is essentially due to an increasing in prevalence of antibiotic-resistant bacteria, which has led to the search for alternative therapies. In this study, we discuss the usage of natural extracts mixture as alternative or complementary agents in controlling H. pylori infection so here, we focused on the plant extracts of (Cloves, Pepper, Cumin, Sage, Pomegranate peel, Ginger, Myrrh and Licorice). To that end, Phytochemical constituents detection like Tannins, Glycosides, Alkaloids, Flavonoids, Terpenoids, Saponins, Phenolic compounds, Reducing sugars, Volatile oils, Amino acids and Proteins was demonstrated. Each plant extract was examined individually or in combination for its antimicrobial activity against H. pylori. Out of the used extracts, four mixes were prepared and tested against H. pylori. The antibacterial activities of the four mixes, represented by the diameter of inhibition clear zone, recorded 21, 39, 23 and 28 mm. The most potent mix (mix2) was chosen and mixed with baby milk as a new combination for H. pylori infections treatment in babies.