Timeline of the Development of Skin-Lightening Active Ingredients in Japan

Quantification of Arbutin and its degradation products, hydroquinone and p-Benzoquinone, in hyperpigmentation topical formulation: Effect of extraction procedure and interference assessment

The utilization of Hydroquinone (HQ) in over-the-counter skincare items is subject to restrictions. Consequently, Arbutin (AR) serves as a reliable alternative for addressing hyperpigmentation in non-prescription topical formulations. Nevertheless, AR undergoes decomposition into HQ and p-Benzoquinone (BZ) when exposed to temperature stress, ultraviolet light, or dilution in an acidic environment, all of which can induce skin toxicity. The intention of this paper is to investigate the effect of extraction procedure on the conversion of AR to HQ and or BZ and to evaluate kinetics of AR hydrolysis to HQ. Meanwhile this study aims to evaluate AR and BZ interference with the United States Pharmacopoeia (USP) identification and assessment method for HQ Hydrolytic stress during extraction conditions underwent optimization through systematic screening tests. Subsequent assessment of the residual drug and its degradation products were achieved by HPLC method. The resulting data were meticulously fitted to various kinetic models. To analyze the potential interference of AR in HQ measurement using USP method, the standard concentrations of AR and HQ were analyzed through UV-VIS spectrophotometry. For enhanced certainty, a validated HPLC method analysis was also conducted. Notably, the acid hydrolysis of AR exhibited independence from its initial concentration. So, the hydrolytic degradation of AR exhibited a Zero-order kinetic profile. Furthermore, the proven interference of AR in the UV-VIS spectrophotometry method was identified within the context of the USP method. This study successfully utilized an adopted HPLC method for the concurrent quantification of AR, HQ, and BZ. The potential interference of AR in the UV-VIS spectrophotometric assay for HQ may lead to false results especially for regulatory purposes.

Efficacy and safety of mesotherapy with tranexamic acid versus vitamin C in the treatment of melasma: A meta-analysis and systemic review

BACKGROUND

The exact pathogenesis of melasma is not yet known, and its treatment remains challenging. Mesotherapy with tranexamic acid (TXA) and vitamin C was both reported to have certain effects on melasma. In spite of that several articles have compared the efficacy and safety of the two drugs on melasma, most of them were clinical study with small sample size.

AIMS

To evaluate the efficacy and safety of mesotherapy with TXA versus vitamin C in treating melasma through meta-analysis and systemic review.

METHODS

The authors searched PubMed, Web of Science, Springer, and ScienceDirect for studies that compared mesotherapy with TXA versus vitamin C as a treatment for melasma. Primary outcomes were change in melasma area and severity index (MASI) before and after the treatment.

RESULTS

Finally, five studies with a total of 127 patients were included in the systematic review. There was no statistic difference in the change in MASI score between the TXA and vitamin C groups (mean difference, 0.16; 95% CI, -0.79 to 1.11).

CONCLUSIONS

Mesotherapy with both TXA and vitamin C is safe and effective in the treatment of melasma.

Mechanism of Action of Topical Tranexamic Acid in the Treatment of Melasma and Sun-Induced Skin Hyperpigmentation

Tranexamic acid (TXA) has anti-plasmin activity and has been shown when administered orally to be effective against melasma, for which it is considered first-line pharmacotherapy. Several studies have shown that topically applied TXA is also effective against melasma and skin hyperpigmentation caused by sunburn and inflammation. The TXA concentration in the epidermis and dermis/vasculature has been estimated from its distribution in the skin after closed application, and topically applied TXA has thus been shown to act on neutrophils and mast cells in the dermis and on the vascular system. It is unlikely that topically applied TXA acts on dermal neutrophils or mast cells or on the vascular system to form thrombi. As discussed in the present review, studies on the effects of topical TXA on the hyperpigmentation process indicate that the resulting skin-lightening mechanism involves the suppression of cytokine/chemical mediator production, which stimulates melanin production via the keratinocyte-derived urokinase-type plasminogen activator and plasminogen derived from dermal vascular in the basal layer of the epidermis, thereby suppressing the production of excessive melanin to prevent hyperpigmentation.