Nanodispersions appertain to the cosmeceuticals1. They can contain solid or liquid nanoparticles.
Solid nanoparticles occur in a broad range of variants:
- Nanocrystals of nearly insoluble and high-melting organic substances such as boswellic acids (frankincense), phytosterols, ceramides, flavones and their glycosides (e.g. rutin)
- Lipid nanoparticles made of waxes, poly-alpha-olefins and other hydrocarbons. They coalesce on the skin and form occlusive films from where lipid-soluble active agents as e.g. coenzyme Q10 are released.
- Polymer globules of polyamides, polypeptides or polysaccharides with embedded, mostly pharmaceutical drugs
- Silica nanoparticles (silicic acid) which can absorb and stabilize amorphous active agents and pigments in their pores
- Inorganic substances such as titanium dioxide, zinc oxide and carbon ("carbon black") for sun protection purposes or decorative cosmetics
Liquid nanoparticles based on phosphatidylcholine are biodegradable and penetrate into the skin in the form of individual molecular components instead of intact particles. They comprise:
- Nanoparticles with lipid-soluble active agents such as vitamins, coenzyme Q10, flavones, ceramides, saponins, vegetable oils with essential fatty acids (omega 3, omega 6) and boswellic acids (frankincense)
- Liposomes with water-soluble vitamins, antioxidants, moisturizers, isoflavones, wrinkle relaxants, tyrosinase inhibitors and polar active agents in general
With exception of the biodegradable liquid nanoparticles, all nanoparticles smaller than 100 nanometer (nm) have to be indicated as nanomaterial.
The alcohol contents of nanodispersal sera and active agent concentrates often are supposed to have dehydrating effects. Since concentrations are low and the evaporation rate high, alcohol is insignificant in this context. Due to the presence of alcohol however no allergenic preservatives are required.
Washout effects, by contrast, are caused by the tensidic components used in combination with nanocrystals. They can be identified in the INCI by denominations as for instance polysorbate 20, polysorbate 80, caprylyl/capryl glucoside, coco-glucoside, lauryl glucoside and decyl glucoside. They are polyethylene glycols (PEG) and sugar tensides which also are components of cleansing gels („rinse-off preparations").
Washout effect means that the emulsifiers or tensides contained in skin care products ("leave-on preparations") virtually leach out the skin. Surface active compounds that are not degraded in the skin become activated during skin cleansing and cause a loss of natural skin barrier substances from inside. The transepidermal water loss increases and the skin becomes dehydrated.
Mostly there are alternatives how active agents can be processed into nanodispersions. Boswellic acids (frankincense) are an example here since they can be used as base for solid nanocrystals2 or liquid nanoparticles.3,4 Liquid nanoparticles will not lead to washout effects and are appropriate preparations for dry skin and problem skins.
Overviews on nanodispersions were presented in a three part workshop on the occasion of the 19. Annual Meeting of the Society for Dermopharmacy (GD) at Berlin, March 18, 2015.5,6,7 References
- Lautenschläger H, Highly effective - Cosmeceuticals, medical Beauty Forum 2014 (4), 16-18
- Müller RH, Schmidt C, Trebeljahr R, Lautenschläger H und Keck CM, Boswellia smartCrystals for Dermal Application: Production and Stability, 2014 AAPS Annual Meeting and Exposition, San Diego, Poster M1078
- Lautenschläger H, Frankincense - the resin with healing power, medical Beauty Forum 2015 (4), 12-16
- Boswelllia Nanoparticles (dermaviduals® modular)
- Müller RH, Historische Entwicklung und heutiger Stand der Technik von nanodispersen Formulierungen, 19. GD-Jahrestagung, Berlin, 18.3.2015
- Lautenschläger H, Indikationsmäßige Anwendungen von Nanodispersionen, 19. GD-Jahrestagung, Berlin, 18.3.2015
- Keck CM, Galenik von Nanodispersionen und praxisrelevante gesetzliche Bestimmungen, 19. GD-Jahrestagung, Berlin, 18.3.2015
Dr. Hans Lautenschläger