Preparation and Evaluation of Nanoemulsion Formulation Containing Kojic Acid and Kojyl 3-aminopropylphosphonic Acid.

BACKGROUND: The kojyl 3-aminopropylphosphonic acid (KAP) was synthesized by kojic acid (KA) with a 3-aminopropylphosphonic acid. Which is more stable than KA and showed better skin penetration and anti-pigmentation efficacy in melanocytes. However, up till now, there have been no studies aimed at incorporating KAP into an emulsion system and evaluating its effectiveness. OBJECTIVE: We develop a novel skin-lightening agent using KAP as the active ingredient and a low-cytotoxic nanoemulsion as the delivery system in this study. METHOD: The sorbitan monooleate and polysorbate surfactants with polyethylene glycol (PEG) co-surfactant were used to generate a nanoemulsion system. RESULT: The transparency and particle size stability over various storage times indicate that the formulated nanoemulsions are suitable for long-term storage. Besides, results demonstrate that the anti-pigmentation function of KA and KAP-containing nanoemulsions (NE-KA and NEKAP) evidently outperformed that of the non-packed KA and KAP group. Despite having the lowest concentration among other treatments, NE-KAP was able to reduce melanin content to approximately 80% of the blank. CONCLUSION: Our findings suggest that this newly developed nanoemulsion containing KAP could potentially serve as a sustainable alternative to hydroquinone for treating dermal hyperpigmentation disorders in future applications.

Using a Cellular System to Directly Assess the Effects of Cosmetic Microemulsion Encapsulated DeoxyArbutin.

DeoxyArbutin (dA) is a tyrosinase inhibitor that has effective skin-lightening activity and has no obvious cytotoxicity toward melanocytes. With the aim of directly evaluating the effects of microemulsions containing dA on cells, we developed oil-in-water (O/W) microemulsions with relatively lower cytotoxicities by using polysorbate-series surfactants. Measurement of the transparent properties and particle size analysis at different storage time periods revealed that the developed microemulsions were stable. Moreover, the developed microemulsions had direct effects on B16-F10 mouse melanoma cells. The anti-melanogenesis activities of dA-containing microemulsions were evidently better than that of the free dA group. The results demonstrated that the developed microemulsion encapsulating dA may allow the use of deoxyArbutin instead of hydroquinone to treat dermal hyperpigmentation disorders in the future.

Study of Hydroquinone Mediated Cytotoxicity and Hypopigmentation Effects from UVB-Irradiated Arbutin and DeoxyArbutin.

Arbutin (Arb) and deoxyArbutin (dA) are both effective hypopigmentation agents. However, they are glucoside derivatives of hydroquinone (HQ), which may be decayed into HQ under higher energy environments. Therefore, safety and toxicity are very important issues when considering the usage of these compounds. However, no study has verified the properties of Ultra-Violet B (UVB)-irradiated Arb and dA. In this work, we investigated the cytotoxicity and hypopigmentation effects of UVB-irradiated Arb and dA in Detroit 551 human fibroblast cells and B16-F10 mouse melanoma cells. The results showed that UVB-irradiated Arb and dA have strong cytotoxicity for the fibroblast cells, especially for dA, the caspase-3 is also activated by the treatment of UVB-irradiated dA in Detroit 551 cells. The results correlated with the produced HQ. In addition, UVB-irradiated Arb and dA suppressed the production of melanin in melanoma cells; this is due to the release of HQ that compensates for the UVB triggered Arb and dA decomposition.

Comparative study on the photostability of arbutin and deoxy arbutin: sensitivity to ultraviolet radiation and enhanced photostability by the water-soluble sunscreen, benzophenone-4.

Arbutin and deoxy arbutin may release hydroquinone under some conditions. We therefore investigated the photostability of arbutin and deoxy arbutin in an aqueous solution. The results revealed arbutin and deoxy arbutin to be photolabile in an aqueous solution. Deoxy arbutin was less stable than arbutin when exposed to UV radiation. The hydroquinone concentration was also increased during the radiation period in both solutions. Benzophenone-4 could clearly improve the photostability of arbutin during the period of UV radiation, but only slightly enhance the photostability of deoxy arbutin.

Study on the stability of deoxyArbutin in an anhydrous emulsion system.

The skin-whitening agent, deoxyArbutin, is a potent tyrosinase inhibitor that is safer than hydroquinone and arbutin. However, it is thermolabile in aqueous solutions, where it decomposes to hydroquinone. Pharmaceutical and cosmetic emulsions are normally oil-in-water (o/w) or water-in-oil (w/o) systems; however, emulsions can be formulated with no aqueous phase to produce an anhydrous emulsion system. An anhydrous emulsion system could offer a stable vehicle for compounds that are sensitive to hydrolysis or oxidation. Therefore, to enhance the stability of deoxyArbutin in formulations, we chose the polyol-in-silicone, anhydrous emulsion system as the basic formulation for investigation. The quantity of deoxyArbutin and the accumulation of hydroquinone in both hydrous and anhydrous emulsions at various temperatures were analyzed through an established high performance liquid chromatographic (HPLC) method. The results indicated that water increased the decomposition of deoxyArbutin in the formulations and that the polyol-in-silicone, oil-based, anhydrous emulsion system provided a relatively stable surrounding for the deoxyArbutin that delayed its degradation at 25 °C and 45 °C. Moreover, the composition of the inner hydrophilic phase, containing different amounts of glycerin and propylene glycol, affected the stability of deoxyArbutin. Thus, these results will be beneficial when using deoxyArbutin in cosmetics and medicines in the future.

Screen-printed carbon electrodes modified with cobalt phthalocyanine for selective sulfur detection in cosmetic products.

Cobalt phthalocyanine (CoPc) films were deposited on the surface of a screen-printed carbon electrode using a simple drop coating method. The cyclic voltammogram of the resulting CoPc modified screen-printed electrode (CoPc/SPE) prepared under optimum conditions shows a well-behaved redox couple due to the (Co(I)/Co(II)) system. The CoPc/SPE surface demonstrates excellent electrochemical activity towards the oxidation of sulfur in a 0.01 mol·L(-1) NaOH. A linear calibration curve with the detection limit (D(L), S/N = 3) of 0.325 mg·L(-1) was achieved by CoPc/SPE coupled with flow injection analysis of the sulfur concentration ranging from 4 to 1120 mg·L(-1). The precision of the system response was evaluated (3.60% and 3.52% RSD for 12 repeated injections), in the range of 64 and 480 mg·L(-1) sulfur. The applicability of the method was successfully demonstrated in a real sample analysis of sulfur in anti-acne creams, and good recovery was obtained. The CoPc/SPE displayed several advantages in sulfur determination including easy fabrication, high stability, and low cost.