Targeting epidermal Langerhans cells by epidermal powder immunization.
(57/772)
Immune reactions to foreign or self-antigens lead to protective immunity and, sometimes, immune disorders such as allergies and autoimmune diseases. Antigen presenting cells (APC) including epidermal Langerhans cells (LCs) play an important role in the course and outcome of the immune reactions. Epidermal powder immunization (EPI) is a technology that offers a tool to manipulate the LCs and the potential to harness the immune reactions towards prevention and treatment of infectious diseases and immune disorders. (+info)
Trojan particles: large porous carriers of nanoparticles for drug delivery.
(58/772)
We have combined the drug release and delivery potential of nanoparticle (NP) systems with the ease of flow, processing, and aerosolization potential of large porous particle (LPP) systems by spray drying solutions of polymeric and nonpolymeric NPs into extremely thin-walled macroscale structures. These hybrid LPPs exhibit much better flow and aerosolization properties than the NPs; yet, unlike the LPPs, which dissolve in physiological conditions to produce molecular constituents, the hybrid LPPs dissolve to produce NPs, with the drug release and delivery advantages associated with NP delivery systems. Formation of the large porous NP (LPNP) aggregates occurs via a spray-drying process that ensures the drying time of the sprayed droplet is sufficiently shorter than the characteristic time for redistribution of NPs by diffusion within the drying droplet, implying a local Peclet number much greater than unity. Additional control over LPNPs physical characteristics is achieved by adding other components to the spray-dried solutions, including sugars, lipids, polymers, and proteins. The ability to produce LPNPs appears to be largely independent of molecular component type as well as the size or chemical nature of the NPs. (+info)
Effect of powder polydispersity on aerosol generation.
(59/772)
PURPOSE: We investigated the effect of primary powder polydispersity on the generation of pharmaceutical powder aerosols, using mannitol and bovine serum albumin (BSA) as the model compounds. METHODS: Primary powders with different polydispersity but comparable physical and mass median aerodynamic diameter (MMAD) were obtained from spray drying. The polydispersity, i.e. the width of the particle size distribution, of the primary powder was measured by the span. Span = [particle diameter at 90% cumulative size] - [particle diameter at 10% cumulative size] / [particle diameter at 50% cumulative size]. A small span indicates a narrow size distribution. Solid state properties and the aerosol behaviour of the powders were determined. RESULTS: For both compounds, dispersion of the smaller span powder generated more fine particles below the MMAD of the primary powder, but the increase was less apparent at high air flows or with a high dispersion efficiency inhaler. With the Dinkihaler, however, the smaller span powder of BSA, but not of mannitol, was found to experience less impaction loss and capsule and device retention. This could be due to the BSA powder being more cohesive, as it was amorphous and had a higher residual moisture content than that of mannitol. CONCLUSIONS: The present study has demonstrated that the amount of fines available in the aerosol could be modified by the primary powder polydispersity. (+info)
Successful treatment of severe hyperammonemia using sodium phenylacetate powder prepared in hospital pharmacy.
(60/772)
In order to treat a hyperammonemic patient with adult-onset type-II citrullinemia (CTLN2), sodium phenylacetate powder was prepared from chemical reagent grade phenylacetic acid in Gunma University Hospital. After purification by recrystalization, phenylacetic acid was neutralized with sodium carbonate and dried at 70 degrees C under reduced pressure. A solution of the prepared powder produced a single peak of m/z=181.0 (M+Na+) in electrospray-ionization-MS spectrogram. The content of phenylacetate was 74% of theoretical value, suggesting the existence of water of crystallization. The content of phenylacetate remained constant for 5 months under dark conditions at room temperature. The prepared sodium phenylacetate powder was orally administered to a 16-year-old patient with CTLN2 at a dosage of 12 g/d. The serum ammonia concentration of the patient, who did not show adequate response to intravenous arginine or oral sodium benzoic acid decreased remarkably to less than 100 microg/dl. Sodium phenylacetate powder should be an essential drug for the treatment of hyperammonemia caused by an inborn error of the urea cycle. (+info)
Influence of physical parameters and lubricants on the compaction properties of granulated and non-granulated cross-linked high amylose starch.
(61/772)
Cross-linked high amylose starch (CLA) is a pharmaceutical excipient used in direct compression for the preparation of controlled release tablets and implants. In this work the compression properties of CLA in bulk and granulated forms (without binder) were evaluated for the first time. Tablets were prepared on an instrumented single punch machine. The flow properties and the compression characteristics (compressibility, densification behavior, work of compression) of the materials as well as the mechanical strength of the finished compacts (compactibility) were systematically examined. Wet granulation was found to improve the flowability and the compressibility of CLA but concomitantly reduced its compactibility. It was demonstrated that CLA was a plastically deforming material with a plasticity index and a yield pressure value comparable to those of pregelatinized starch. The compactibility of granulated CLA was independent of particle size in the range of 75 to 500 microm, but slightly decreased when the percentage of the fine particles (<75 microm) in the bulk powder was increased. Water and colloidal silicone dioxide facilitated the consolidation of CLA, while magnesium stearate had an opposite effect on the tablet crushing force. (+info)
Design of controlled release system with multi-layers of powder.
(62/772)
Pellets containing active ingredients were coated with water-insoluble powders, i.e. hydrogenated caster oil (Lubliwax (WAX)) and magnesium stearate (Mg-St). The influences of the structural difference of the sustained release layer and curing conditions on the drug release rate were investigated. Sodium valproate (VP-Na) was used as a highly water-soluble model drug. Drug release profiles were influenced by the combination of the WAX layer and the Mg-St layer. Even if the formula of sustained release layers were the same, drug release rate could be affected by the structural difference of the controlled release layer. The Mg-St layer was more effective in prolonging drug release than the WAX layer. Compared with single and double layer types, the triple layer (sandwich) type was most effective in obtaining a long sustained drug release. Heat-treatment retarded drug release mainly by increasing the density of the sustained release layer of the WAX. The Mg-St was effective in protecting the agglomeration between particles during heat-treatment. Optimal heat-treatment conditions were found to exist. Scanning electron microscopy (SEM) analysis indicated that heat-treatment caused the WAX to melt, formed a film-like structure and made the release layer dense. Furthermore, heat-treatment changed the release pattern of VP-Na from sustained release pellets with a multi-layer of powder, leading to zero-order release. (+info)
Removal of fine powders from film surface. I. Effect of electrostatic force on the removal efficiency.
(63/772)
A novel fine particle removal system composed of a corona-discharge neutralizer, a pulse-jet air unit and an image processing system has been developed. First of all, adhesion force between particle and film was directly measured and effect of electrostatic force on the adhesion force was calculated experimentally and theoretically. The electrostatic force was found to be significant, leading to the suggestion that the countermeasure for the electrostatic force was required to effectively remove fine particles. This system was then applied to the removal of fine particles from surface of a gelatin film used for conventional capsule material. The number of particles removed by the system was calculated by an image processing system and number base removal efficiency was computed with and without the elimination of electrostatic charge by the neutralizer. It was found that the difference between the removal efficiency of particles with elimination of electrostatic charge and that of without the elimination showed linear relationship with the electrostatic adhesion force. The data confirmed the necessity of electrostatic charge elimination for the effective removal of fine particles. (+info)
Removal of fine powders from film surface. II. Effect of operating parameters on the removal efficiency.
(64/772)
In the previous paper, a novel fine particle removal system composed of a corona-discharge neutralizer, a pulse-jet air unit and an image processing system has been developed and applied to the removal of fine particles from film surface. We have calculated the van der Waals and electrostatic forces between particle and film and then reported that the electrostatic force influenced the adhesion characteristics significantly and thus the elimination of electrostatic charge should be necessary for the effective removal of fine particles. In this paper, we have modified the corona-discharge neutralizer for getting much better removal performance. The effect of operating parameters on the removal efficiency was investigated experimentally. The ratio of fine particle remained on the film surface after removal experiment as a function of particle size was measured. It was found that fine particles smaller than 15 microm, which were impossible to remove by other conventional techniques, could be almost completely removed. This method is anticipated to be used in the capsule filling, film packaging and tabletting processes for prevention of stain on lens of video automatic inspection machines, unpredictable movement of electronic devices, and deteriorates of product quality. (+info)