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Tea catechins are a group of flavonoids that show many bioactivities. Catechins have been extensively reported as a potential treatment for skin disorders, including skin cancers, acne, photoaging, cutaneous wounds, scars, alopecia, psoriasis, atopic dermatitis, and microbial infection. In particular, there has been an increasing interest in the discovery of cosmetic applications using catechins as the active ingredient because of their antioxidant and anti-aging activities. However, active molecules with limited lipophilicity have difficulty penetrating the skin barrier, resulting in low bioavailability. Nevertheless, topical application is a convenient method for delivering catechins into the skin. Nanomedicine offers an opportunity to improve the delivery efficiency of tea catechins and related compounds. The advantages of catechin-loaded nanocarriers for topical application include high catechin loading efficiency, sustained or prolonged release, increased catechin stability, improved bioavailability, and enhanced accumulation or targeting to the nidus. Further, various types of nanoparticles, including liposomes, niosomes, micelles, lipid-based nanoparticles, polymeric nanoparticles, liquid crystalline nanoparticles, and nanocrystals, have been employed for topical catechin delivery. These nanoparticles can improve catechin permeation via close skin contact, increased skin hydration, skin structure disorganization, and follicular uptake. In this review, we describe the catechin skin delivery approaches based on nanomedicine for treating skin disorders. We also provide an in-depth description of how nanoparticles effectively improve the skin absorption of tea catechins and related compounds, such as caffeine. Furthermore, we summarize the possible future applications and the limitations of nanocarriers for topical delivery at the end of this review article.

Background No willingness-to-pay (WTP) per quality-adjusted life-year (QALY) value exists for the Kingdom of Saudi Arabia (KSA). Objective The primary objective of this study was to determine the WTP for a QALY in the KSA. Methods Adult citizens of the KSA, patients with cancer, or members of the general public (MGP) were recruited to participate in a time trade-off survey to elicit health utilities. Cancer was chosen as the disease of interest for patients and the MGP, with a scenario describing stage 3 colorectal cancer, because it is a disease condition that impacts on both quality of life and survival time. In a second step, respondents were asked about their WTP to move from the estimated health state to a state of perfect health for 1 year (QALY). Finally, that amount was processed to generate the WTP for a full QALY. The second step was repeated with a 5-year horizon. Sensitivity analyses were performed without outliers. Results From 400 participants, data from 378 subjects were obtained and usable: 177 patients, 201 MGP; 278 male, 100 female subjects; 231 aged 26–65 years. Demographic distribution varied widely between the two subgroups for age, education level, and employment status, but with less variation in sex and income. Elicited health utilities were 0.413 (0.472 after adjustment) for the overall group, 0.316 (0.416) for patients, and 0.499 (0.508) for MGP. Overall WTP for a QALY was $US25,600 (adjusted $US32,000) for the 1-year horizon and $US19,200 (adjusted $US22,720) for the 5-year horizon. Conclusion This was the first empirical attempt to estimate the WTP per QALY for the KSA. Results are comparable to those in some other countries and to gross domestic product figures for the KSA. Further research in a country-wide sample is warranted. Electronic supplementary material The online version of this article (10.1007/s41669-020-00211-0) contains supplementary material, which is available to authorized users.

As a continuing effort to elucidate the impact of structure modification upon cutaneous absorption behavior, we attempted to assess the skin permeation of magnolol by methylation and acetylation.Diacetylmagnolol and 2-O-acetyl-2'-O-methylmagnolol (AMM) were designed and synthesized in this study. The anti-inflammatory activity against stimulated neutrophils and keratinocytes was evaluated to check the bioactivity of the analogues. In vitro skin absorption was investigated using nude mouse and pig skin models at both equimolar and saturated doses.Magnolol generally showed the strongest anti-inflammatory potential, followed by diacetylmagnolol and AMM. The antibacterial activity was observed for magnolol and diacetylmagnolol but not AMM. Diacetylmagnolol and AMM could be partly hydrolyzed to magnolol and 2-O-methylmagnolol after entering the skin. The hydrolysis rate of diacetylmagnolol was faster than that of AMM. The lipophilicity played a crucial role in cutaneous absorption, with AMM exhibiting the highest skin deposition. AMM accumulation within nude mouse skin was about 2.5-fold greater than that of magnolol and diacetylmagnolol. On the other hand, the transdermal penetration across the skin was lessened by methylation and esterification. This led to a superior skin targeting of AMM. Although the pharmacological activity of AMM was low, the high skin uptake and bioconversion into 2-O-methylmagnolol in the skin contributed to a greater therapeutic index (TI, skin deposition x inflammatory inhibition percentage) compared to the others. The accumulation of AMM in the hair follicles was 77.12 nmol/cm(2), which was significantly greater than that with magnolol (44.84 nmol/cm(2)) and diacetylmagnolol (26.96 nmol/cm(2)). The synthetic analogues were tolerable to the nude mouse skin.Based on the experimental results, we may suggest topically applied AMM as a potent and safe candidate for the treatment of cutaneous inflammation.

In this study, we aimed to illustrate the utility of fractional radiofrequency (RF) that generated microchannels in the skin, allowing delivery of peptide and siRNA via the skin. The mechanisms involved in the correlation between macromolecule permeation and skin structure were also elucidated. The morphology of the skin was examined by transmission electron microscopy (TEM), higher harmonic generation microscopy (HGM), and physiological factors. In vivo skin distribution of macromolecules was assessed by fluorescence and confocal microscopies. RF thermolysis selectively created an array of micropores deep into the epidermis without significant removal of the stratum corneum (SC). With energy of 30 mJ, a pore depth of 35 μm was achieved. The bipolar RF resulted in a 3-fold increase of transepidermal water loss (TEWL) compared with intact skin. The respective skin accumulation and flux of the peptide with a molecular weight (MW) of 2335 Da was 3- and 23-fold greater for the RF-treated group than for the non-treatment group. RF enhanced skin accumulation of siRNAs with MW of 10 and 15 kDa by 6.2- and 2.6-fold, respectively. Cutaneous penetration of the macromolecules with an MW of at least 40 kDa could be accomplished by RF. Confocal microscopy imaging revealed that RF could effectively deliver the peptide up to at least a 74-μm depth. The penetration depth of siRNA by RF irradiation was about 50 μm. The novel RF device efficiently delivered macromolecules into the skin while reserving SC layers to support some barrier functions. In this work, for the first time the assistance of fractional RF on peptide and siRNA transport was demonstrated.