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The application of ATR-FTIR spectroscopy and multivariate data analysis to study drug crystallisation in the stratum corneum

Goh CF, Craig DQ, Hadgraft J, Lane ME

Eur J Pharm Biopharm, 2017 Feb;111:16-25.
PMID: 27845181 DOI: 10.1016/j.ejpb.2016.10.025

Drug permeation through the intercellular lipids, which pack around and between corneocytes, may be enhanced by increasing the thermodynamic activity of the active in a formulation. However, this may also result in unwanted drug crystallisation on and in the skin. In this work, we explore the combination of ATR-FTIR spectroscopy and multivariate data analysis to study drug crystallisation in the skin. Ex vivo permeation studies of saturated solutions of diclofenac sodium (DF Na) in two vehicles, propylene glycol (PG) and dimethyl sulphoxide (DMSO), were carried out in porcine ear skin. Tape stripping and ATR-FTIR spectroscopy were conducted simultaneously to collect spectral data as a function of skin depth. Multivariate data analysis was applied to visualise and categorise the spectral data in the region of interest (1700-1500cm(-1)) containing the carboxylate (COO(-)) asymmetric stretching vibrations of DF Na. Spectral data showed the redshifts of the COO(-) asymmetric stretching vibrations for DF Na in the solution compared with solid drug. Similar shifts were evident following application of saturated solutions of DF Na to porcine skin samples. Multivariate data analysis categorised the spectral data based on the spectral differences and drug crystallisation was found to be confined to the upper layers of the skin. This proof-of-concept study highlights the utility of ATR-FTIR spectroscopy in combination with multivariate data analysis as a simple and rapid approach in the investigation of drug deposition in the skin. The approach described here will be extended to the study of other actives for topical application to the skin.

Matched MeSH terms: Epidermis/drug effects*
Fulltext A randomized half-body, double blind, controlled trial on the effects of a pH-modified moisturizer vs. standard moisturizer in mild to moderate atopic dermatitis

Goh SW, Jamil A, Safian N, Md Nor N, Muhammad N, Saharudin NL

An Bras Dermatol, 2020 03 21;95(3):320-325.
PMID: 32291095 DOI: 10.1016/j.abd.2019.11.007

BACKGROUND: Higher skin pH in atopic dermatitis contributes to impaired epidermal barrier. A moisturizer compatible with physiological pH could improve atopic dermatitis.
OBJECTIVE: To determine the effect of a physiologically compatible pH moisturizer in atopic dermatitis.
METHODS: A randomized half body, double blind, controlled trial involving patients with stable atopic dermatitis was performed. pH-modified moisturizer and standard moisturizer were applied to half body for 6 weeks.
RESULTS: A total of 6 (16.7%) males and 30 (83.3%) females participated. Skin pH reductions from week 0, week 2 and 6 were significant at the forearms (5.315 [0.98] to 4.85 [0.54] to 5.04 [0.78], p=0.02) and abdomen (5.25 [1.01], 4.82 [0.64], 5.01 [0.59], p=0.00) but not at the shins (5.01 [0.80], 4.76 [0.49], 4.85 [0.79], p=0.09) with pH-modified moisturizer. Transepidermal water loss (TEWL) at the forearms decreased (4.60 [2.55] to 3.70 [3.10] to 3.00 [3.55], p=0.00), abdomen (3.90 [2.90] to 2.40 [3.45] to 2.70 [2.25], p=0.046). SCORAD improved from 14.1±12.75 to 10.5±13.25 to 7±12.25, p=0.00. In standard moisturizer group, pH reductions were significant at the forearms (5.29 [0.94] to 4.84 [0.55] to 5.02 [0.70], p=0.00) and abdomen (5.25 [1.09], 4.91 [0.63], 5.12 [0.66], p=0.00). TEWL at the forearm were (4.80 [2.95], 4.10 [2.15], 4.60 [3.40], p=0.67), shins (3.80 [1.40], 3.50 [2.35], 4.00 [2.50], p=0.91) and abdomen (3.70 [2.45], 4.10 [3.60], 3.40 [2.95], p=0.80). SCORAD improved from 14.2±9.1 to 10.9±10.65 to 10.5±11, p=0.00. Reduction in pH was observed with both moisturizers while TEWL significantly improved with pH-modified moisturizer. pH-modified moisturizer resulted in greater pH, TEWL and SCORAD improvements however the differences were not significant from standard moisturizer.
STUDY LIMITATION: Skin hydration was not evaluated.
CONCLUSION: Moisturization is beneficial for atopic dermatitis; use of physiologically compatible pH moisturizer is promising.

Matched MeSH terms: Epidermis/drug effects
Pigmentation and dermal conservative effects of the astonishing algae Sargassum polycystum and Padina tenuis on guinea pigs, human epidermal melanocytes (HEM) and Chang cells

Quah CC, Kim KH, Lau MS, Kim WR, Cheah SH, Gundamaraju R

Afr J Tradit Complement Altern Med, 2014;11(4):77-83.
PMID: 25392585

BACKGROUND: The preference for a fairer skin-tone has become a common trend among both men and women around the world. In this study, seaweeds Sargassum polycystum and Padina tenuis were investigated for their in vitro and in vivo potentials in working as skin whitening agents. Seaweed has been used as a revolutionary skin repairing agent in both traditional and modern preparations. The high antioxidant content is one of the prime reasons for its potent action. It has been employed in traditional Chinese and Japanese medicine. For centuries, most medical practitioners in the Asian cultures have known seaweed as an organic source of vitamins, minerals, fatty acids like omega-3 and omega-6 and antioxidants. The present objective of the study was to evaluate the potent dermal protective effect of the two seaweeds Sargassum polycystum and Padina tenuis on human cell lines and guinea pigs.
MATERIAL AND METHODS: Seaweeds were extracted with ethanol and further fractionated with hexane, ethyl acetate and water. The extracts were tested for mushroom tyrosinase inhibitory activity, cytotoxicity in human epidermal melanocyte (HEM), and Chang cells. Extracts with potent melanocytotoxicity were formulated into cosmetic cream and tested on guinea pigs in dermal irritation tests and de-pigmentation assessments.
RESULTS: Both Sargassum polycystum and Padina tenuis seaweeds showed significant inhibitory effect on mushroom tyrosinase in the concentration tested. SPEt showed most potent cytotoxicity on HEM (IC50 of 36µg/ml), followed by SPHF (65µg/ml), and PTHF (78.5µg/ml). SPHF and SPEt reduced melanin content in skin of guinea pigs when assessed histologically.
CONCLUSION: SPEt, SPHF and PTHF were able to inhibit HEM proliferation in vitro, with SPHF being most potent and did not cause any dermal irritation in guinea pigs. The results obtained indicate that SPHF is a promising pharmacological or cosmetic agent.

Matched MeSH terms: Epidermis/drug effects
Fulltext Counteracting the Ramifications of UVB Irradiation and Photoaging with Swietenia macrophylla King Seed

Mahendra CK, Abidin SAZ, Htar TT, Chuah LH, Khan SU, Ming LC, et al.

Molecules, 2021 Apr 01;26(7).
PMID: 33916053 DOI: 10.3390/molecules26072000

In this day and age, the expectation of cosmetic products to effectively slow down skin photoaging is constantly increasing. However, the detrimental effects of UVB on the skin are not easy to tackle as UVB dysregulates a wide range of molecular changes on the cellular level. In our research, irradiated keratinocyte cells not only experienced a compromise in their redox system, but processes from RNA translation to protein synthesis and folding were also affected. Aside from this, proteins involved in various other processes like DNA repair and maintenance, glycolysis, cell growth, proliferation, and migration were affected while the cells approached imminent cell death. Additionally, the collagen degradation pathway was also activated by UVB irradiation through the upregulation of inflammatory and collagen degrading markers. Nevertheless, with the treatment of Swietenia macrophylla (S. macrophylla) seed extract and fractions, the dysregulation of many genes and proteins by UVB was reversed. The reversal effects were particularly promising with the S. macrophylla hexane fraction (SMHF) and S. macrophylla ethyl acetate fraction (SMEAF). SMHF was able to oppose the detrimental effects of UVB in several different processes such as the redox system, DNA repair and maintenance, RNA transcription to translation, protein maintenance and synthesis, cell growth, migration and proliferation, and cell glycolysis, while SMEAF successfully suppressed markers related to skin inflammation, collagen degradation, and cell apoptosis. Thus, in summary, our research not only provided a deeper insight into the molecular changes within irradiated keratinocytes, but also serves as a model platform for future cosmetic research to build upon. Subsequently, both SMHF and SMEAF also displayed potential photoprotective properties that warrant further fractionation and in vivo clinical trials to investigate and obtain potential novel bioactive compounds against photoaging.

Matched MeSH terms: Epidermis/drug effects