Compendium of the most significant studies with reference to properties, intake, effects.

Weber S, Schrag K, Mildau G, Kuballa T, Walch SG, Lachenmeier DW. Analytical Methods for the Determination of Mineral Oil Saturated Hydrocarbons (MOSH) and Mineral Oil Aromatic Hydrocarbons (MOAH)-A Short Review. Anal Chem Insights. 2018 Jun 4;13:1177390118777757. doi: 10.1177/1177390118777757. 

Abstract. Mineral oils (such as paraffinum liquidum or white oil), which consist of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH), are widely applied in various consumer products such as medicines and cosmetics. Contamination of food with mineral oil may occur by migration of mineral oil containing products from packaging materials, or during the food production process, as well as by environmental contamination during agricultural production. Considerable analytical interest was initiated by the potential adverse health effects, especially carcinogenic effects of some aromatic hydrocarbons. This article reviews the history of mineral oil analysis, starting with gravimetric and photometric methods, followed by on-line-coupled liquid chromatography with gas chromatography and flame ionization detection (LC-GC-FID), which still is considered as gold standard for MOSH-MOAH analysis. Comprehensive tables of applications in the fields of cosmetics, foods, food contact materials, and living organisms are provided. Further methods including GCxGC-MS methods are reviewed, which may be suitable for confirmation of LC-GC-FID results and identification of compound classes. As alternative to chromatography, nuclear magnetic resonance (NMR) spectroscopy has recently been suggested for MOSH-MOAH analysis, especially with the possibility of detecting only the toxicologically relevant aromatic rings. Furthermore, NMR may offer potential as rapid screening especially with low-field instruments usable for raw material control.

Samadi, A., Khosrowpour, Z., Nasrollahi, S. A., Ayatollahi, A., & Firooz, A. (2021). Protective effects of moisturizers on skin barrier during regular hand washing with soap bars. Indian Journal of Dermatology, 66(2), 207.

Abstract. ...The increase in TEWL and skin pH immediately after washing with a soap was considerably reduced with the application of moisturizer [Figure [Figure2a2a and and2b].2b]. Reduction in TEWL is because of occlusive agents presented in the moisturizer (paraffinum liquidum, cyclomethicone, and beeswax), which form an inactive layer on the skin surface, and physically block water evaporation from the skin...

Stamatas, G. N., de Sterke, J., Hauser, M., von Stetten, O., & van der Pol, A. (2008). Lipid uptake and skin occlusion following topical application of oils on adult and infant skin. Journal of Dermatological Science, 50(2), 135-142.

Abstract. Topical application of oils and oil-based formulations is common practice in skin care for both adults and infants. Only limited knowledge however is available regarding skin penetration and occlusive potential of oils and common methods for measuring skin moisturization fall short when it comes to the moisturizing effect of oils.

Partenhauser, A., Zupančič, O., Rohrer, J., Bonengel, S., & Bernkop‐Schnürch, A. (2016). Thiolated silicone oils as adhesive skin protectants for improved barrier function. International Journal of Cosmetic Science, 38(3), 257-265.

Abstract. Objective The purpose of this study was the evaluation of thiolated silicone oil as novel skin protectant exhibiting prolonged residence time, enhanced barrier function and reinforced occlusivity....Results Silicone thiomers showed pronounced substantivity on skin with 22.1 ± 6.3% and 39.2 ± 6.7% remaining silicone after 8 h for silicone-TGA and silicone-MPA, respectively, whereas unmodified silicone oil and dimethicone were no longer detectable. In particular, silicone-MPA provided a protective shield against artificial urine penetration with less than 25% leakage within 6 h. An up to 2.5-fold improved water vapour impermeability for silicone-MPA in comparison with unmodified control was discovered with the Payne cup model. In addition, for silicone-MPA a reduced TEWL by two-thirds corresponding to non-thiolated control was determined for up to 8 h. Conclusion Thiolation of silicone oil leads to enhanced skin adhesiveness and barrier function, which is a major advantage compared to commonly used silicones and might thus be a promising treatment modality for various topical applications.

Sapino, S., Oliaro-Bosso, S., Zonari, D., Zattoni, A., & Ugazio, E. (2017). Mesoporous silica nanoparticles as a promising skin delivery system for methotrexate. International journal of pharmaceutics, 530(1-2), 239-248.

Abstract. The systemic administration of methotrexate (MTX), a commonly used, antineoplastic drug which is also used in cutaneous disorders, is primarily associated with prolonged retention in the body and consequently with side effects. Innovative drug delivery techniques and alternative administration routes would therefore contribute to its safe and effective use. The general objective of this study is thus the development of MTX-based preparations for the topical treatment of skin disorders. MCM-41-like nanoparticles (MSN), are herein proposed as carriers which can improve the cutaneous absorption and hence the bioavailability and efficacy of MTX. The MTX/MSN complex, prepared via the impregnation procedure, has been physico-chemically characterized, while its cell cultures have had their biocompatibility and bioactivity tested. Furthermore, a series of stable MTX-based dermal formulations has been developed, some containing shea butter, a natural fat. Ex-vivo porcine skin absorption and the transepidermal permeation of MTX have also been monitored in a variety of media using Franz diffusion cells. Interestingly, the epidermal accumulation of the active molecule was increased by its inclusion into MSN, regardless of the surrounding medium. Furthermore, the presence of shea butter enhanced the skin uptake of the drug both in the free and in the loaded form.

Saloranta, K., & Westermarck, T. (2005). Prevention of cerumen impaction by treatment of ear canal skin. A pilot randomized controlled study. Clinical Otolaryngology, 30(2), 112-114.

Abstract. Objectives: To evaluate the effect of topical skin treatment of the ear canal in the prevention of impacted earwax....Main outcome: The main outcome was recurrence of impacted earwax with complete obstruction of the ear canal. There was significantly lower recurrence rate of impacted earwax in the treated compared with the control group (23%versus 61%, P < 0.05). Conclusions: This study suggests that prophylactic treatment of the ear canal with a topical emollient may prevent formation of impacted earwax.

Spada, F., Harrison, I. P., Barnes, T. M., Greive, K. A., Daniels, D., Townley, J. P., ... & Shumack, S. (2021). A daily regimen of a ceramide‐dominant moisturizing cream and cleanser restores the skin permeability barrier in adults with moderate eczema: A randomized trial. Dermatologic Therapy, 34(4), e14970.

Abstract. The dysfunctional skin barrier in eczema patients may be attributed to decreased levels of ceramides in the stratum corneum. The aim of this study was to determine whether a two-part system consisting of a ceramide-dominant physiological lipid-based moisturizing cream and cleanser could ameliorate the signs and symptoms of moderate eczema in adults over 28 days compared to placebo. Assessments were conducted at baseline and every 7 days thereafter. Eczema area severity index score decreased significantly across all time points in both groups compared to baseline (P < .0001), however, this decrease was not significant between groups at day 28 (P = .7804). In contrast, transepidermal water loss and skin hydration significantly improved over time in the active group, while it either stayed the same or worsened in the placebo group (P = .0342 and P < .0001, respectively). There was no difference in the use of mometasone furoate as rescue medication over time between groups (P = .1579). Dermatology life quality index scores improved significantly in both groups (P < .0001), with no difference between groups (P = .5256). However, patient satisfaction was greater in the active compared to the placebo group for several parameters including relief of itch, dry skin, skin softness and smoothness (all P < .05). No patients withdrew from the study due to adverse events (AEs) and there were no serious AEs. The ceramide-dominant moisturizing cream and cleanser safely restores skin permeability and improves the signs and symptoms of eczema in adults.