PREPARATION AND SCALE-UP STUDY OF TREATED FAMOTIDINE FOR THE DEVELOPMENT OF ORALLY DISINTEGRATING TABLETS USING A COMPLEX FLUIDIZED-BED GRANULATOR EQUIPPED WITH A PARTICLE-SIZING MECHANISM

Objective: Bitter taste-masked drug substance should be needed for the development of orally disintegrating tablets (ODT). We selected a new type of a complex fluidized-bed granulator equipped with a particle-sizing mechanism for treating famotidine (FAM). This study was conducted to demonstrate the critical process parameter, which controls particle size of treated FAM, to determine its acceptable particle size considering uniformity of assay and to perform scale-up study from a laboratory scale to a commercial scale.Methods: Particle size of treated FAM was evaluated by changing spraying air pressure on the operation of a complex fluidized-bed granulator. Uniformity of assay in granules after blending and tablets were compared at different particle size of treated FAM. On the scale-up study, particle size and assay of treated FAM in both scales were evaluated.Results: The particle size of treated FAM decreased as the increase in spraying air pressure in relation to the spraying mist size. Better uniformity of assay was observed when the diameter of treated FAM was 20 µm compared to that of 50 µm. Therefore, target particle size of treated FAM was set at approximately 20 µm. Similar qualities could be obtained between both scales in the points of particle size and assay.Conclusion: On the operation of a complex fluidized-bed granulator, spraying air pressure was the critical process parameter that controlled particle size of treated FAM. On Scale-up study of treated FAM, spraying air pressure in relation to the spraying mist size was important

Spin order in the charge disproportionated phases of the A-site layer ordered triple perovskite LaCa2Fe3O9

International audienceThe coupling between spins and charge disproportionation states has been investigated in the LaCa 2 Fe 3 O 9 oxide with neutron powder diffraction. This A-site layer ordered triple perovskite LaCa 2 Fe 3 O 9 undergoes charge disproportionation on cooling and shows two different charge ordering patterns. At 230 K, Fe 3.67+ disproportionates into a 2:1 ratio of Fe 3+ :Fe 5+ which order in a layered manner along the <010> direction of the pseudocubic unit cell. At lower temperatures (T < 170 K), the charge ordering pattern changes to a layered arrangement along the <111> direction. Neutron powder diffraction data shows that in the intermediate temperature range (170 K < T < 230 K) the spins order into a cycloidal structure on the ac plane for the Fe 3+ cations while the Fe 5+ cations remain paramagnetic. For the lowest temperature range (2 K < T < 190 K), the spin structure follows the charge ordering and evolves to a <111> layered magnetic structure. Introduction

Determination of Elemental Ratio in an Atomic Column by Electron Energy Loss Spectroscopy

Atomic-resolution quantification of the elemental ratio of Fe to Mn at the octahedral and tetrahedral sites in brownmillerite Ca₂Fe_1.07Mn_0.93O₅ was determined using electron energy-loss spectroscopy combined with aberration-corrected scanning transmission electron microscopy. The combined techniques revealed that oversampling of the spectral imaging data yielded a spatially resolved area that very nearly reflects atomic resolution (∼1.2 Å radius). The average experimental ratios of Fe to Mn within this region were 17.5:82.5 for the octahedral sites and 81.6:18.4 for the tetrahedral sites. The elemental ratio in an octahedral atomic column was successfully extracted by estimating the mixing of signals from nearest neighbor columns. The results indicated that the ratio of Fe to Mn was 13:87 at the octahedral site, which is in good agreement with the results of neutron diffraction analysis. In addition, the uncertainty of experimental results obtained by using an average 1.2 Å radius was less than 10% at octahedral sites, depending on the sample thickness. In contrast, the experimental error due to dechanneling of incident electrons was larger at the tetrahedral sites. This experimental procedure has wide application for determining the spatially resolved composition ratio of elements in perovskite-like compounds

Two Charge Ordering Patterns in the Topochemically Synthesized Layer-Structured Perovskite LaCa₂Fe₃O₉ with Unusually High Valence Fe^3.67+

A-site-ordered layer-structured perovskite LaCa₂Fe₃O₉ with unusually high valence Fe^3.67+ was obtained by low-temperature topochemical oxidation of the A-site layer-ordered LaCa₂Fe₃O₈. The unusually high valence Fe^3.67+ in LaCa₂Fe₃O₉ shows charge disproportionation of Fe³⁺ and Fe⁵⁺ first along the layer-stacking ⟨010⟩ direction below 230 K. Fe³⁺ is located between the La³⁺ and Ca²⁺ layers, while Fe⁵⁺ is between the Ca²⁺ layers. The two-dimensional electrostatic potential due to the A-site layered arrangement results in the quasi-stable ⟨010⟩ charge ordering pattern. Below 170 K, the charge ordering pattern changes, and the 2:1 charge-disproportionated Fe³⁺ and Fe⁵⁺ ions are ordered along the ⟨111⟩ direction. The ground-state charge ordering pattern is stabilized primarily by the electrostatic lattice energy, and the Fe⁵⁺ ions are arranged to make the distances between the nearest neighboring Fe⁵⁺ as large as possible