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In this work, external circulation rotating packed bed (EX-RPB) was combined with internal circulation rotating packed bed (IN-RPB) for the preparation of Y-type oxotitanium phthalocyanine nanocrystals (Y-TiOPc NCs) for the first time. The operating conditions in EX-RPB and in IN-RPB were investigated in detail. X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet–visible (UV-vis) absorption spectroscopy analysis, and elemental analysis were performed, and xerographic properties were analyzed, to characterize the products. The experimental results indicated Y-TiOPc NCs with the average size of 6 nm were successfully prepared. The Q-band absorption peak of Y-TiOPc NCs centered at 782 nm, implying their potential application in the xerographic photoreceptors of laser printers. The photoreceptor fabricated with Y-TiOPc NCs exhibited an initial surface potential of 703.56 V, a photosensitivity of 0.166 μJ/cm2, a residual potential of 26.48 V, and a dark decay rate of 10.64 V/s. This wo...

For many water insoluble acidic or alkaline drugs, amorphization and nanonization represent an effective bioavailability enhancement strategy. Cefixime (CFX) was chosen as a model drug, and amorphous nanoparticles were prepared via a typical process intensification technology: high-gravity reactive precipitation (HGRP). The effects of temperature, rotating speed, overall flow rate, and drug concentration on the particle size and size distribution were investigated. Under the optimum conditions, spherical nanoparticles with a mean size of 45 nm could be precipitated. After filtration, redispersion and spray-drying processes, the obtained CFX nano-powder showed a good stability and exhibited a tremendously enhanced saturation solubility, reaching ∼11 times higher than that of raw CFX. Furthermore, CFX nano-powder achieved 100% drug dissolution within 2 min while raw CFX did not dissolve completely after 45 min. Since the production capacity of lab-scale RPB reached 2.3 kg/h, HGRP method might offer a general platform for mass production of drug nanoparticles without the use of organic solvents and pharmaceutical additives.

To enhance the solubility and dissolution rate, and thus potentially improve the oral bioavailability of cefixime (CFX), amorphous CFX nanoparticles were prepared via high-gravity antisolvent precipitation (HGAP) without the aid of any pharmaceutical additives in a rotating packed bed (RPB). The effects of operating variables on particle size and distribution were investigated. Compared to raw CFX, the mean size of prepared nanoparticles decreased greatly from about 2.1 μm to 57 nm, and the saturation solubility increased tremendously from 0.289 to 0.951 mg/mL. CFX nanoparticles showed good stability and were capable of generating a maximum supersaturation level, reaching up to ∼22.8 times of raw CFX’s saturation solubility. Further, CFX nanoparticles achieved 100% drug dissolution within 2 min, while the raw drug did not dissolve completely after 45 min, suggesting that the solubility and dissolution properties of CFX nanoparticles were significantly improved. Since the drug recovery ratio achieved 99.9%...