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This study investigates the improvements in direct compaction powder properties achieved through particle design using laboratory and pilot-scale spray dryers. Hydroxypropyl methylcellulose and polyvinylpyrrolidone were used as modifying agent, which have low hygroscopicity and surface tension, good flowability, and excellent compactibility. Ammonium bicarbonate and sodium bicarbonate were used as pore-forming agents, and the composite particles were prepared using laboratory and pilot-scale spray dryers. The results showed that the structure of the composite particles and porous particles can effectively improve the flowability, tabletability, and disintegration behaviour; the composite particles prepared by laboratory-scale spray drying have better tabletability; the composite particles prepared by spray drying at pilot-scale had better flowability. In summary, there are significant differences in the properties of products prepared by different scales of spray drying. It will be beneficial to choose the appropriate equipment and the appropriate experimental design. Consequently, this study may contribute to the development of natural plant tablets. [ABSTRACT FROM AUTHOR]

To elucidate the roles of vitrification of stabilizers/matrix formers for the redispersibility of drug nanocrystal powder after solidification at storage stress, the influence of different drying methods and storage stresses on stability of drug nanocrystals was systemically investigated. A poorly soluble drug, baicalin, used as model drug was converted into baicalin nanocrystals (BCN-NC). The residual moisture contents of BCN-NC were applied at two different stress conditions defined as 'conservative' (<1%) and 'aggressive' (>1%), respectively. The influence of different stabilizers, matrix formers, and storage stresses on the redispersibility of BCN-NC powder was systemically investigated, respectively. The results showed that storage stresses had significantly influence the redispersibility of BCN-NC. Aggressive storage temperature and residual moisture could be unfavorable factors for stability of drug nanocrystals, due to the exacerbation of aggregation of BCN-NC induced by vitrification. It was demonstrated that vitrification of spray-dried BCN-NC was dependent on temperature and time. The polymeric stabilizers hydroxypropylmethylcellulose (HPMC) and sodium carboxymethyl starch (CMS-Na) with high glass transition temperature ( T ) played more important role in protecting the BCN-NC from breakage during storage, compared to the surfactants Tween 80, d-α-tocopherol acid polyethylene glycol 1000 succinate (TPGS), or RH 40. Besides, the polyvinylpyrrolidone K30 (PVP K30) and lactose with high T were effective matrix formers for preserving the redispersibility of BCN-NC. It was concluded that the vitrification transition of stabilizers/matrix formers could be responsible for aggregation of drug nanocrystals during storage, which was a time-dependent process. The suitable residual moisture contents (RMC) and T were very important for preserving the stability of drug nanocrystals during storage. [ABSTRACT FROM AUTHOR]