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Nanopowders, Thin Films, and Devices | |
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 Pharmaceutical Particle Size Reduction Two general routes exist to reduce pharmaceutical particle size. Top-down approaches such as high-pressure homogenization and wet or dry ball milling utilize mechanical means to physically break up larger particles into smaller ones. In these processes, ~98% of the energy input into the system is converted to heat versus effective particle size reduction. These routes can often result in thermal or mechanical degradation reducing medical efficacy particularly with temperature-sensitive materials. nGimat's NanoSpraySM Process has the advantage of being a bottom-up approach in which active pharmaceutical ingredient (API) molecules dissolved in solution are atomized and precipitated into small particles in a single-stage, low-cost technique. The addition of excipients to the precursor solution offers the possibility of producing solid excipient/API solutions in order to aid in stabilization of the final nanopowder. nGimat is utilizing its novel atomization technique to reduce the particle size of API to the sub-micron scale. Many existing APIs are poorly water soluble, which results in poor bioavailability. Twenty percent of drugs launched since 1995 have sub-optimal performance due to low bioavailability resulting in decreased specificity, slow onset of action, variability by patient and by food intake, high dosage, poor compliance, and increased side effects. Reducing the particle size of an API to the nanometer regime is an effective route for improving water solubility and absorption kinetics through increased surface area and reduced dissolution energy via crystallinity. Typically, the stability of such small particles is a concern due to the low glass transition temperatures associated with most APIs, resulting in gradual agglomeration and particle growth as well as reorientation of the material into a crystalline phase. To improve the stability of the produced API nanoparticles, FDA-approved excipients may be easily incorporated into NanoSpray processing to produce nanoparticles dispersed in an excipient matrix. APIs located in Class II of the biopharmaceutical classification system are characterized as having low solubility and high gastrointestinal permeability. These materials are primary candidates for improved performance through particle size reduction and will be targeted for potential processing using the NanoSpray Processing technique. A demonstration of the Nanomiser® Device's ability to atomize and convert conventional drugs into micronized powder was performed using un-optimized NanoSpray processing and lysozyme. A solution of lysozyme in water was prepared and pumped through the Nanomiser Device, which resulted in the formation of a fine aerosol. This aerosol was then exposed to slow cooling, which resulted in formation of a fine lysozyme powder. The original lysozyme has a plate-like morphology with dimensions between 50-300 microns. NanoSpray processing resulted in the formation of lysozyme powder with nearly spherical particles and sizes <3 microns. Smaller size greatly increases bioavailability thus reducing dosage and costs.
Medical Materials Hydroxyapatite, calcium phosphate, and YSZ nanopowders and nanostructured films are used in dentistry, prosthetics, and medical implants. These materials can be used to produce implants and devices with improved reliability and biological compatibility and to surface treat metal implants (titanium) to enable improved acceptance and bone growth. Sufficiently small nanoparticles may enable improved processing in dense bodies with good mechanical and biological properties.
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