The therapeutic effects of curcumin in treating Alzheimer's disease (AD) depend on the ability to penetrate the blood-brain barrier. The latest nanoparticle technology can help to improve the bioavailability of curcumin, which is affected by the final particle size and stability. We developed a stable curcumin nanoparticle formulation to test in vitro and in AD model Tg2576 mice. Flash nanoprecipitation of curcumin, polyethylene glycol-polylactic acid co-block polymer, and polyvinylpyrrolidone in a multi-inlet vortex mixer, followed by freeze drying with β-cyclodextrin, produced dry nanocurcumin with mean particle size <80 nm. Nanocurcumin powder, unformulated curcumin, or placebo was orally administered to Tg2576 mice for 3 months. Before and after treatment, memory was measured by radial arm maze and contextual fear conditioning tests. Nanocurcumin produced significantly (p=0.04) better cue memory in the contextual fear conditioning test than placebo and tendencies toward better working memory in the radial arm maze test than ordinary curcumin (p=0.14) or placebo (p=0.12). Amyloid plaque density, pharmacokinetics, and Madin-Darby canine kidney cell monolayer penetration were measured to further understand in vivo and in vitro mechanisms. Nanocurcumin produced significantly higher curcumin concentration in plasma and six times higher area under the curve and mean residence time in brain than ordinary curcumin. The P(app) of curcumin and tetrahydrocurcumin were 1.8×10(-6) and 1.6×10(-5)cm/s, respectively, for nanocurcumin. Our novel nanocurcumin formulation produced highly stabilized nanoparticles with positive treatment effects in Tg2576 mice.

Phase behaviors of 1:1 profen-nicotinamide cocrystal systems were delineated by constructing their temperature-composition phase diagrams. Cocrystallization with nicotinamide can simultaneously improve tableting behavior, hygroscopicity, and dissolution performance of ibuprofen and flurbiprofen. This could pave the way for further development of such cocrystal systems into consistent, stable, efficacious and readily manufacturable drug products.

Nanoparticles are considered to be a powerful approach for the delivery of poorly water-soluble drugs. One of the main challenges is developing an appropriate method for preparation of drug nanoparticles. As a simple, rapid and scalable method, the flash nanoprecipitation (FNP) has been widely used to fabricate these drug nanoparticles, including pure drug nanocrystals, polymeric micelles, polymeric nanoparticles, solid lipid nanoparticles, and polyelectrolyte complexes. This review introduces the application of FNP to produce poorly water-soluble drug nanoparticles by controllable mixing devices, such as confined impinging jets mixer (CIJM), multi-inlet vortex mixer (MIVM) and many other microfluidic mixer systems. The formation mechanisms and processes of drug nanoparticles by FNP are described in detail. Then, the controlling of supersaturation level and mixing rate during the FNP process to tailor the ultrafine drug nanoparticles as well as the influence of drugs, solvent, anti-solvent, stabilizers and temperature on the fabrication are discussed. The ultrafine and uniform nanoparticles of poorly water-soluble drug nanoparticles prepared by CIJM, MIVM and microfluidic mixer systems are reviewed briefly. We believe that the application of microfluidic mixing devices in laboratory with continuous process control and good reproducibility will be benefit for industrial formulation scale-up.

The existence of a cocrystal between curcumin (CUR) and phloroglucinol (PHL) was suspected but could not be demonstrated in a recent systematic effort to synthesize novel curcumin cocrystals. We hypothesize that the elusive CUR–PHL cocrystal is a kinetically stable form that can be prepared by trapping it using a fast solvent removal crystallization process. The polarity of crystallization solvent and relative solubility of cocrystal formers in the solvent appear to be critical parameters governing the phase purity of the resulting cocrystal. Organic solvents of higher polarity and in which the cocrystal formers exhibited congruent solubility tended to afford a purer cocrystal phase. Essentially phase-pure CUR–PHL cocrystals were successfully obtained from acetone, and their 1:1 stoichiometry was confirmed by differential scanning calorimetry and solid state nuclear magnetic resonance spectroscopy. Compared with the individual component phases, the cocrystal displayed reduced hygroscopicity and improved tabletability. However, the intrinsic dissolution rate of the cocrystal showed no significant improvement compared with the pure CUR crystal due to the instantaneous conversion of the cocrystal to CUR at its surface upon contact with the dissolution medium.