A novel adsorbent to remove ammonia in gas-phase via chemisorption was successfully developed. It was clarified that the crystal morphology and adsorption properties of adsorbent differ P/Si ratio for preparation. When P/Si is 1.2, nearly single phase Si₅(PO₄)₆O was obtained. As a result of adsorption experiments, exothermic reaction was observed and then mass gradually gained for P/Si ≤ 1.2. By contrast, when P/Si was larger than 1.2 quite a large amount of water vapor was observed together with exothermic reaction which resulted in extremely irregular mass change. The adsorption capacity of sample of P/Si = 1.2 was 8.132 mmol/g and this value was in good agreement with theoretical value of 8.264 mmol/g. The conversion was estimated to be 98.4%.

In many clinically-approved nucleic acid products, transfection agents, including viral vectors and lipid nanoparticles, have been applied for high transfection efficiency, whereas they have major concerns about severe systemic adverse action. Inhaled dry powder formulations for naked nucleic acids without transfection agents are highly attractive because of many practical advantages, such as direct and noninvasive delivery to the lungs where nuclease activity is low, easy usage, good device portability, and high storage stability. However, various physical stresses generated in the production process can destabilize nucleic acids, and there are few articles demonstrating the efficacy of the naked nucleic acid powders produced. The present article introduces our outcomes about the stability of naked nucleic acids under several types of physical treatment or powder formation and about the successful development of inhaled dry naked nucleic acid powders with high aerosol performance and superior pulmonary transfection efficiency.