Freeze-drying is an effective way to improve long-term physical stability of nanosuspension in drug delivery applications. Nanosuspension also known as suspension of nanoparticles. In this study, the effect of freeze-drying with different cryoprotectants on the physicochemical characteristics of resveratrol (RSV) nanosuspension and quercetin (QUE) nanosuspension was evaluated. D-α-tocopheryl polyethylene glycol succinate (TPGS) and folate-modified distearoylphosphatidyl ethanolamine-polyethylene glycol (DSPE-PEG-FA) were selected as functional stabilisers formulated nanosuspension which were prepared by anti-solvent precipitation method. RSV nanoparticle size and QUE nanoparticle size were about 210 and 110 nm, respectively. The AFM and TEM results of nanosuspension showed uniform and irregular shape particles. After freeze-drying, the optimal concentration of four cryoprotectants was determined by the particle size of re-dispersed nanoparticles. The dissolution profile of drug nanoparticle significantly showed approximately at a 6-8-fold increase dissolution rate. Moreover, TPGS and DSPE-PEG-FA stabilised RSV nanosuspension and QUE nanosuspension samples showed better effect on long-term physical stability.

The poor penetration and low bioavailability are the main challenges for transdermal drug delivery. Nanocrystals technology is an attractive method for water-insoluble drug transdermal delivery, as the literature demonstrated that the penetration and bioavailability of the transdermal delivered water-insoluble drugs significantly enhanced and improved by the nanocrystals technology. Currently, the nanocrystals technology has been applied in transdermal delivery of cosmeceutical and for therapy of skin diseases, such as diclofenac acid, tretinoin and rutin. This review focused on the advantages of the nanocrystals technology for transdermal delivery. The special features of nanocrystals for the transdermal delivery of poorly soluble drugs are reviewed (skin disease treatment, safety and compliance, applying to cosmeceutical). Furthermore, the factors of influencing the nanocrystals penetration and the approaches of improving nanocrystals transdermal delivery are also discussed in detail.

Exploring the metabolic disturbance of fipronil and its derivatives in aquatic organisms may provide a more comprehensive understanding of the impact of fipronil on ecological environment. In this work, internal...