Nα-Benzyl-L-histidine methyl ester dihydrochloride

The interaction of hydrogen chloride (HCl) with ice surfaces at temperatures between 190 and 220 K was investigated using a coated-wall flow-tube connected to a chemical ionization mass spectrometer. Equilibrium surface coverages of HCl were determined at gas phase concentrations as low as 2 × 109 molecules cm-3 (∼4 × 10-8 Torr at 200 K) to derive Langmuir adsorption isotherms. The data are described by a temperature independent partition coefficient: KLang = (3.7 ± 0.2) × 10-11 cm3 molecule-1 with a saturation surface coverage Nmax = (2.0 ± 0.2) × 1014 molecules cm-2. The lack of a systematic dependence of KLang on temperature contrasts the behaviour of numerous trace gases which adsorb onto ice via hydrogen bonding and is most likely related to the ionization of HCl at the surface. The results are compared to previous laboratory studies, and the equilibrium partitioning of HCl to ice surfaces under conditions relevant to the atmosphere is evaluated.

OBJECTIVES: Renal function may progressively decline in patients with Fabry disease. This study assessed pharmacokinetics, safety, and tolerability of a single oral dose of migalastat HCl 150 mg in subjects with normal or mildly, moderately, or severely impaired renal function.

Methods used to quantify inositol phosphates in seeds lack the sensitivity and specificity necessary to accurately detect the lower concentrations of these compounds contained in the leaves of many plants. In order to measure inositol hexakisphosphate (InsP₆) and inositol pentakisphosphate (InsP₅) levels in leaves of different plants, a method was developed to concentrate and pre-purify these compounds prior to analysis. Inositol phosphates were extracted from leaves with diluted HCl and concentrated on small anion exchange columns. Reversed-phase solid phase extraction cartridges were used to remove compounds that give peaks that sometimes interfere during HPLC. The method permitted the determination of InsP₆ and InsP₅ concentrations in leaves as low as 10 µM and 2 µM, respectively. Most plants analyzed contained a high ratio of InsP₆ to InsP₅. In contrast, certain members of the Malvaceae family, such as cotton (Gossypium) and some hibiscus (Hibiscus) species, had a preponderance of InsP₅.

The current investigation deals with evaluation of chitosan-hydroxypropyl methylcellulose (HPMC) based polymeric matrices as a carrier for single-unit capsules based on hydrodynamically balanced system (HBS) for stomach-specific floating sustained drug release using moxifloxacin HCl (MX) as a model drug. Various HBS capsules of MX were prepared by physical blending of MX with chitosan (low or medium molecular mass) or HPMC (K4M or K15M) or chitosan-HPMC combinations in varying proportions followed by the encapsulation into size 0 capsules made of hard gelatin. HBS capsules based on chitosan (low and medium molecular weight and their combination) as polymer matrix failed to float on 0.1 N HCl (pH 1.2). Whereas, formulations containing HPMC (K4M or K15M) or their mixture with chitosan, remained buoyant and released MX over 9 h in the acidic dissolution medium following zero-order kinetics. In conclusion, HPMC (K4M, K15M, blend of K4M and K15M) or their mixture with low/medium molecular mass chitosan may constitute excellent carrier systems for the stomach-specific sustained delivery of MX over a longer period.