Emulsions, Microemulsions, and Lyotropic Liquid Crystals - Surface and Colloid Chemistry: Principles and Applications - page 198

with reduced side effects. Incorporation of the chemical sunscreen tocopherol ace-
tate into SLN prevents chemical degradation and increases the UV-blocking capac-
ity. Aqueous SLN dispersions were produced and incorporated into gels, followed
by particle-size examination, stability testing upon storage, and thermoanalytical
examination. Investigation of the UV-blocking capacity using different in vitro tech-
niques revealed that the SLN dispersions produced in this study are at least twice
as effective as their reference emulsions (conventional emulsions with identical lipid
content). Placebo SLN show even greater UV-blocking efficacy than emulsions con-
taining tocopherol acetate as the molecular sunscreen. Incorporation of tocopherol
acetate into SLN leads to an overadditive UV-blocking effect. Furthermore, film for-
mation of SLN on the skin and occlusivity were examined. The obtained data show
that incorporation of tocopherol acetate into SLN leads to an improved sunscreen
and skin care formulation.
The influence of a cream containing 20% glycerin and its vehicle on skin barrier
properties has been investigated. Recent studies have shown that polymers offer sev-
eral advantages and can be used in skin care products. Phase diagrams were deter-
mined for lactic and isohexanoic hydroxy acids as well as salicylic acid with water,
a nonionic surfactant and a paraffinic oil, to outline the influence of hydroxy acids
on the structure in a model for a skin lotion. The results showed the influence of the
acid to be similar to that of the oil but that the difference in chain length between the
two alpha acids had only insignificant influence. The results are discussed from two
aspects: the structures involved in the lotion as applied, and the action of the lotion
residue on the skin after the evaporation of the water.
In the pharmaceutics literature, an application-triggered drug release from an
O/W emulsion recipe has been reported. The application of emulsions in the phar-
maceutical industry is very important, and a large number of references are found in
the current literature.
9.5.2 T h e p a I n T I n d u S T r y a n d c o l l o I d a l a S p e c T S
Everybody appreciates the function of paint is manyfold:
Appearance
Color
Protection (from corrosion iron, etc.; from deterioration of wood)
Paint is recognized as a pigmentated mixture (in liquid or paste form) that protects
and enhances the appearance of materials. Its role in the case of cars or houses or
wood furniture is well recognized. In the early days (almost 100 years ago), cars
were painted with nitocellulose lacquer. Today, especially, in some areas such as cars
manufacturing, the industrial development of paint has been very extensive. There
are various types of paint industries:
Paint formulation
Paint pigments
Paint rheology and stability