A statistical approach for estimation of significant variables in wet attrition milling

Rapid synthesis of cesium lead halide perovskite nanocrystals by l-lysine assisted solid-phase reaction at room temperature

Nowadays, there are many ways to obtain cesium lead halide perovskite nanocrystals. In addition to the synthesis methods carried out in solution, the solid-phase synthesis was reported involving grinding and milling. In this paper, we synthesized luminescent CsPbBr3/Cs4PbBr6 perovskite nanocrystals (PNCs) by three solid-phase synthesis methods (grinding, knocking, stirring) using l-lysine as a ligand. This is the first attempt to use an amino acid for assisting the solid phase synthesis of perovskite and to study the difference in the products obtained by the three solid phase synthesis methods. The results show that the productivity of the solid-phase synthesis methods can be greatly improved by adding l-lysine and the perovskites obtained by the methods are more resistant to water due to the addition of l-lysine. The simplicity of the synthesis process expanded the use of solid-phase synthesis to obtain more perovskites and provided potential applications of perovskite in analytical detection and sensing in aqueous solution.

Design, development and characterization of ketorolac tromethamine polymeric nanosuspension

Aim: At present, various ophthalmic formulations show low bioavailability. The rationale of present work was to design and develop stable ketorolac tromethamine nanosuspension with sustained effect and greater permeability for ocular drug delivery and increased ocular residence. Materials & methods: Formulations were designed by using central composite design, developed by combined nanoprecipitation and probe sonication method. Results & discussion: Nanosuspensions depicted the size range of the particles in between 199 and 441 nm with slight reduction in crystallinity of drug. In vitro drug release revealed that higher % entrapment efficiency of drug in nanosuspension delays the drug release. Conclusion: Eudragit RL-100-based nanosuspension increases viscosity and avoids problems like drug loss from precorneal surface and rapid drainage through nasolacrimal areas.

Rapid and direct synthesis of complex perovskite oxides through a highly energetic planetary milling

The search for a new and facile synthetic route that is simple, economical and environmentally safe is one of the most challenging issues related to the synthesis of functional complex oxides. Herein, we report the expeditious synthesis of single-phase perovskite oxides by a high-rate mechanochemical reaction, which is generally difficult through conventional milling methods. With the help of a highly energetic planetary ball mill, lead-free piezoelectric perovskite oxides of (Bi, Na)TiO₃, (K, Na)NbO₃ and their modified complex compositions were directly synthesized with low contamination. The reaction time necessary to fully convert the micron-sized reactant powder mixture into a single-phase perovskite structure was markedly short at only 30-40 min regardless of the chemical composition. The cumulative kinetic energy required to overtake the activation period necessary for predominant formation of perovskite products was ca. 387 kJ/g for (Bi, Na)TiO₃ and ca. 580 kJ/g for (K, Na)NbO₃. The mechanochemically derived powders, when sintered, showed piezoelectric performance capabilities comparable to those of powders obtained by conventional solid-state reaction processes. The observed mechanochemical synthetic route may lead to the realization of a rapid, one-step preparation method by which to create other promising functional oxides without time-consuming homogenization and high-temperature calcination powder procedures.

An Intensified Vibratory Milling Process for Enhancing the Breakage Kinetics during the Preparation of Drug Nanosuspensions

As a drug-sparing approach in early development, vibratory milling has been used for the preparation of nanosuspensions of poorly water-soluble drugs. The aim of this study was to intensify this process through a systematic increase in vibration intensity and bead loading with the optimal bead size for faster production. Griseofulvin, a poorly water-soluble drug, was wet-milled using yttrium-stabilized zirconia beads with sizes ranging from 50 to 1500 μm at low power density (0.87 W/g). Then, this process was intensified with the optimal bead size by sequentially increasing vibration intensity and bead loading. Additional experiments with several bead sizes were performed at high power density (16 W/g), and the results were compared to those from wet stirred media milling. Laser diffraction, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and dissolution tests were used for characterization. Results for the low power density indicated 800 μm as the optimal bead size which led to a median size of 545 nm with more than 10% of the drug particles greater than 1.8 μm albeit the fastest breakage. An increase in either vibration intensity or bead loading resulted in faster breakage. The most intensified process led to 90% of the particles being smaller than 300 nm. At the high power intensity, 400 μm beads were optimal, which enhanced griseofulvin dissolution significantly and signified the importance of bead size in view of the power density. Only the optimally intensified vibratory milling led to a comparable nanosuspension to that prepared by the stirred media milling.