Page 529 - Book Hosokawa Nanoparticle Technology Handbook

21 DEVELOPMENT OF FUNCTIONAL SKINCARE COSMETICS APPLICATIONS
APPLICATION 21

21 DEVELOPMENT OF FUNCTIONAL SKINCARE COSMETICS USING
BIODEGRADABLE PLGA NANOSPHERES

Cosmetics incorporating “nanotechnology” and of the skin cells causing the collapse of phospholipid
claiming the inclusion of “nano-size ingredients” and association bodies and the leak of their encapsulated
“nanoparticles” have appeared considerably on the ingredients. As a result, their ability to transport active
consumer market over the past few years. Many man- ingredients to deep skin is not likely good. Meanwhile,
ufacturers of the skincare products (e.g. creams, the use of macromolecular (PLGA) nanosphere, a
lotions, beauty essences, etc.) use ultra high-pressure shape-stable nanoparticle carrier, is being developed.
emulsification and other techniques to nano size their We encapsulated three vitamin derivatives in PLGA
active ingredients down to tens of nanometers, which nanospheres, including vitamin C (ascorbyl tetraiso-
are smaller than the gaps between the skin cells in the plamitate), vitamin E (tocopherol acetate) and vitamin
corneum layer (70 nm), with an attempt to improve A (retinyl palmitate); and marketed a new type of func-
their skin permeability and absorbability. Many liquid tional skin care product, which requires mixing of these
liposomes and solid particles, such as the pro-vitamin A nanospheres with beauty essence at the time of use [2].
loaded calcium carbonate nanoparticles [1] and the These nanospheres have an average size of 200 nm,
pro-vitamin C loaded PLGA (poly lactide-co-glycolide) which was found to be the largest size that permeates
nanospheres are recently utilized as nanocosmetics not only skin pores (200–300 nm) but also the horny
carriers to enhance the performance of cosmetic layer in the cutaneous permeability experiment as
products. In this section, we would focus on the pro- described below. The job of the PLGA nanospheres is
vitamin C loaded PLGA nanospheres technology and to permeate the melanocytes in the stratum basale of
use it as an example of solid type carrier for creating the epidermis and the fibroblasts in the dermis; and
functional skincare cosmetics. then, gradually release their vitamin derivatives over
48 h due to hydrolysis by the skin moisture. The
1. Nanocosmetics that whiten skin and eliminate released vitamin derivatives are converted to pure vita-
wrinkles mins by esterase in the body and show pharmacologi-
cal effect as illustrated in Fig. 21.1 near the target area.
(1) The pharmacological effect of vitamins on the skin For skin whitening and anti-wrinkle/sagging appli-
cations, it is important to have a technology which can
Many people are bothered by the blemishes and wrin-
kles on the skin. Vitamins C, E, and A are believed to nano size the vitamin derivatives, amino acids, and
be effective in mitigating the blemish and wrinkle other active ingredients, so that they can reach the tar-
problems. Vitamin C suppresses the blemishes get areas in a stable form, and sustain the pharmaco-
because it limits the activity of tyrosinase, which pro- logical effect for a long time. In a sense, the idea of
motes melanin production. Furthermore, it increases nanoparticle design for drug delivery systems in cos-
collagen formation to reduce wrinkles, and prevents metics applications is important. Presented below are
cell oxidation by eliminating active oxygen. As to the evaluation of the cutaneous permeability of PLGA
vitamin E and A, they also act as antioxidant and col- nanospheres and their effects on the whitening and
lagen promoter, respectively. Therefore, many whiten- anti-wrinkle of skin [3, 4].
ing and anti-aging cosmetic products apply various
vitamin complexes and their derivatives. But, not 2. Evaluation of the cutaneous permeability of PLGA
many products offer sufficient tangible results, nanospheres and their functional effect [3, 4]
because the corneum layer (the skin’s outermost layer)
acts as a barrier that considerably reduces the absorp- (1) Evaluation of the cutaneous permeability of PLGA
tion rate of the vitamins and other active ingredients.
In addition, the vitamins are decomposed easily under nanospheres
ordinary conditions. To be effective, the vitamins have The cutaneous permeability of PLGA nanospheres
to be functionally refined to enhance their stability was evaluated by using the modified Bronaugh diffu-
and to increase their cutaneous permeability. sion chamber developed by Miwa et al. with human
skin biopsies [3, 5]. Unlike those methods using arti-
(2) Nanocosmetics ficial skin or animal skin, this method allows test
Many liquid-type nanocosmetics carriers, such as lipo- fluid to penetrate the human skin biopsy by natural
somes, are structurally unstable. Specifically, when diffusion, and therefore produces data very close to
passing through the skin, they adhere to the inside walls those obtained in the clinical study.

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