Preparation, characterization, and evaluation of anti-tyrosinase activity of solid lipid nanoparticles containing Undecylenoyl phenylalanine (Sepiwhite®)

BACKGROUND

Hyperpigmentation is darkened patches or spots on the skin occurred by increased melanin. Undecylenoyl phenylalanine (Sepiwhite®), as a commercial lipophilic derivative of phenylalanine, is a powerful new brightener that can be used in the treatment of skin pigmentation disorders.

AIMS

Solid lipid nanoparticles (SLNs) increase the efficiency of hydrophobic drugs. The current study aimed to prepare and characterize SLNs containing Sepiwhite (SEPI-SLN).

METHODS

In this study, an optimized SEPI-SLN formulation was selected by applying the response surface method. In vitro drug loading content, the release profile of SEPI, and cell viability were investigated. The permeation rate of SEPI-SLN was also compared to conventional cream containing Sepiwhite (SEPI-CREAM). Furthermore, the anti-tyrosinase activity of Sepiwhite was also evaluated.

RESULTS

The optimized formulation showed a spherical morphology with particle size and entrapment efficiency of 218.6 ± 11.1 nm and % 87.31 ± 0.65, respectively. Differential scanning calorimetry (DSC) analysis confirmed SEPI-loaded SLN formulation with no drug-lipid incompatibility. The in vitro permeation experiment revealed the enhanced cutaneous uptake of SEPI-SLN. The results also showed that Sepiwhite could stop melanogenesis with inhibition of the tyrosinase enzyme.

CONCLUSION

Our findings confirm that SLNs could be a proper nanocarrier for the relevant usage of Sepiwhite as a powerful brightener agent.

Saccharin Anion Acts as a "Traffic Assistant" of Zn2+ to Achieve a Long-Life and Dendritic-Free Zinc Plate Anode

Due to the great advantages of low cost, high capacity, and excellent safety, the Zn metal is a promising candidate material for rechargeable aqueous battery systems. However, its practical applications have been restricted by the uncontrollable dendrite growth and electrode side reactions (such as corrosion, passivation, and hydrogen evolution reactions) during the plating process. Herein, we reveal that the dendrite growth would expose the electrode to more highly active tips, exacerbating the passivation of the electrode and the decomposition of the electrolyte by in situ optical microscopies. We propose a low-cost, nontoxic, low-concentration (less than 1 g/L), and effective electrolyte additive, saccharin sodium, which can guide an even Zn deposition without obvious electrode side reactions in the charge/discharge process. The saccharin anion acts as a "traffic assistant" of Zn²⁺ and demonstrates its great potential for practical application. The assembled Zn symmetrical battery shows an excellent cycling performance at a high current density and capacity (an extremely long cycle life over 3800 h is obtained at 5 mA/cm² and 8 mA h/cm², and 20 mA/cm² and 5 mA h/cm² show a lifetime over 800 h), and the full cell (coupled to an AC electrode) presents a stable cycle life with a capacity retention of 86.4% even after 8000 cycles at 5 mA/cm². The saccharin sodium proposed in this work is promising to solve the anode problems in advanced Zn batteries.

Effects of Eight Brighteners as Solar Radiation Protectants for Steinernema carpocapsae, All Strain

Seven commercially available Blankophor fluorescent brighteners were compared with the standard Tinopal LPW as solar radiation protectants for Steinernema carpocapsae (All strain). Blankophor BBH and Tinopal LPW were the most successful UV screens, with 95% of the original nematode infectivity to larvae of the greater wax moth, Galleria mellonella, retained after 4 hours of exposure to direct sunlight. The Blankophor HRS and DML preserved 80 and 85% infectivity, and the P167 preserved 70% infectivity after the sunlight exposure. The other Blankophors (RKH, LPG, and BSU) were not as effective.