The Influence of Crystal Habit on the Prediction of Dry Powder Inhalation Formulation Performance Using the Cohesive–Adhesive Force Balance Approach

The aim of this investigation was to study the influence of crystalline habit of active pharmaceutical ingredients on the cohesive–adhesive force balance within model dry powder inhaler (DPI) formulations and the corresponding affect on DPI formulation performance. The cohesive–adhesive balance (CAB) approach to colloid probe atomic force microscopy (AFM) was employed to determine the cohesive and adhesive interactions of micronized budesonide particles against the {102} and {002} faces of budesonide single crystals and crystalline substrates of different sugars (cyclodextrin, lactose, trehalose, raffinose, and xylitol), respectively. These data were used to measure the relative level of cohesion and adhesion via CAB and the possible influence on in vitro performance of a carrier-based DPI formulation. Varying the crystal habit of the drug had a significant effect on the cohesive measurement of micronized budesonide probes, with the cohesive values on the {102} faces being approximately twice that on the {002} crystal faces. However, although different CAB values were measured with the sugars with respect to the crystal faces chosen for the cohesive-based measurement, the overall influence on the rank order of the CAB values was not directly influenced. For these data sets, the CAB gradient indicated that a decrease in the dominance of the adhesive forces led to a concomitant increase in fine particle delivery, reaching a plateau as the cohesive forces became dominant. The study suggested that crystal habit of the primary drug crystals influences the cohesive interactions and the resulting force balance measurements of colloid probe CAB analysis.     

Some Characteristics of Free Cell Population in the Airways of Rats after Intratracheal Instillation of Copper-Containing Nano-Scale Particles

We used stable water suspensions of copper oxide particles with mean diameter 20 nm and of particles containing copper oxide and element copper with mean diameter 340 nm to assess the pulmonary phagocytosis response of rats to a single intratracheal instillation of these suspensions using optical, transmission electron, and semi-contact atomic force microscopy and biochemical indices measured in the bronchoalveolar lavage fluid. Although both nano and submicron ultrafine particles were adversely bioactive, the former were found to be more toxic for lungs as compared with the latter while evoking more pronounced defense recruitment of alveolar macrophages and especially of neutrophil leukocytes and more active phagocytosis. Based on our results and literature data, we consider both copper solubilization and direct contact with cellular organelles (mainly, mitochondria) of persistent particles internalized by phagocytes as probable mechanisms of their cytotoxicity.     

Fracture of Gd2 (MoO4)3 single crystals

Fracture behaviour of Gd2 (MoO4)3 single crystal, which is improper ferroelectric–ferroelastic, has been examined by means of point loading. There are three fracture planes in gadolinium molybdat (GMO): ;100} – main cleavage plane, {210} and {110} – secondary cleavage ones. It is shown that cracks have a tendency to transit from secondary planes up to cubic plane and vice versa. This would be considered as the main cause of river pattern appearance on fracture surfaces of samples. Mechanical twinning and crack growth are independent channels for relaxation of elastic energy in GMO, which do not connected between themselves, so excluding of twinning leads to increase of crack length.     

Composition and submicron structure of thin films of supersaturated Zn x Pb1 − x S solid solutions

Thin films of supersaturated Zn _x Pb_{1 ? x} S solid solutions containing up to 4.1 mol % ZnS have been obtained by hydrochemical deposition. The dependence of the material structure and surface morphology on the film composition has been studied. It is established that an increase in the content of zinc sulfide leads to the growth of grains with a more complicated crystalline structure, the formation of grain boundary fragments with dimensions from 60 to 100 nm, and a modification of the electrical properties of deposited layers.     

Dynamic Frequency-Interference Method of Measuring the Wavelength–Frequency Ratio of Lasers

The frequency-interference method of measurement of the wavelength–frequency ratio of lasers is investigated. A wavelength-dependent frequency shift is formed as a consequence of the Doppler effect produced by rotation of a reflector. The optical circuits and signal detection circuit are presented.