38 SKIN CARE
Sustained actives release using silica aerogel
Naoki Arifuku, Toya Kinoshita, Tadahiro Fukuju – Tokuyama
Tokuyama Corporation of Japan has commercialized a spherical silica aerogel powder, Airlica, for cosmetics applications, which is characterized by its smooth texture derived from its spherical form produced by our proprietary technology. The silica aerogel is a porous material
with a porosity of 90% or more, and because drying shrinkage must be suppressed, it is prepared either by supercritical drying or by surface treatment inside the pores followed by atmospheric pressure drying. The spherical silica aerogel powder has a
high oil absorption capacity due to its extremely high porosity, and it is used as a functional powder to hold makeup and absorb excess sebum. In this study, we focused on this very high
porosity and investigated whether a sustained release effect could be obtained by loading active ingredients into the porosity.
Evaluation method In order to achieve a sustained release effect, it is important to keep the active ingredient inside the pores of the spherical silica aerogel powder until just before use. In other words, if the active ingredient is water-based, the formulation must be oil-rich, and if the active ingredient is oil- based, the formulation must be water-rich. The spherical silica aerogel powder is
produced by modifying the surface and the interior of the pores with trimethylsilyl groups to inhibit drying shrinkage and is therefore a hydrophobic powder. Therefore, they are more suitable for use with oil-based active ingredients than water-based active ingredients. In this study, isopropyl methylphenol (IPMP)
it in the spherical silica aerogel powder. In this study, the active ingredients were dissolved in ethylhexyl palmitate, an oil commonly used in cosmetics, and the dissolved solution was loaded onto the spherical silica aerogel powder. When the spherical silica aerogel powder
loaded with the active ingredient is applied to human skin as a cosmetic, it is desirable to slowly release the active ingredient while mixing with oil such as sebum, and to sustain the action of the active ingredient for a long time. For this reason, we focused on lotion as a
water-rich cosmetic formulation and decided to formulate it in lotion. When the spherical silica aerogel powder, which contains a large amount of oil, is blended in lotion, the oil and water layers separate, so we prevented this separation by making gel lotion with increased viscosity. In this study, the gel lotion containing IPMP-
loaded spherical silica aerogel powder (IPMP concentration 0.1 wt%) was prepared with the composition shown in Table 1. The preparation method is also shown.
was used as the active ingredient. IPMP is a bactericidal ingredient that inhibits the growth of bacteria and is widely used in topical drugs such as ointments and creams, and personal care products such as soap, toothpaste and cosmetics. It is characterized by its average action on a wide range of bacteria and moulds, and by its low odour, low irritancy, and high safety. Since IPMP is a fat-soluble crystal, it was necessary to dissolve it in oil and then support
TABLE 1: GEL LOTION FORMULATION CONTAINING IPMP-LOADED SPHERICAL SILICA AEROGEL POWDER Phase Ingredients / INCI A
Function
Ethylhexyl Palmitate o-Cymen-5-ol (IPMP)
B C Glycerin
D Acrylates/C10-30 Alkyl Acrylate Crosspolymer Dimethicone
E 6 N Sodium Hydroxide Water
F
PEG-100 Hydrogenated Castor Oil Alcohol
Emollient Antibacterial Silica Silylate (The spherical silica aerogel powder) Carrier
Moisturiser Thickener
Improved skin feel pH control Base
Interfacial active agent Antibacterial agent, styptic
% w/w 1.6 0.1
0.3 6.0 0.4 2.0 0.4
83.2 1.0
5.0
Procedure:Mix component A with component B. Add component C to the mixture in (1) to make a paste. Mix component D and make a paste. Mix component E and make a paste. Mix component E, and while stirring, add component little by little. After adding, add component D in the same manner. Add component F
Evaluation of acne-preventive effect of gel lotion containing IPMP-loaded spherical silica aerogel powder by analysis of porphyrin score We examined whether the prepared gel lotion was effective in preventing acne. The method was to apply the lotion to the human face and observe the rate of increase of acne bacilli after application to evaluate the slow-release effect. The observation of acne bacteria was
conducted by measuring the amount of porphyrin in the skin before and after lotion application by analyzing UV-photographed images using a skin image analyzer, VISIA Evolution (manufactured by Canfield Scientific). Porphyrin is a metabolite of Bacillus/
Cutibacterium acnes, the main pathogen of acne, and fluoresces and emits light when exposed to UV light. When a subject’s face is photographed during UV irradiation, the porphyrins present on the face emit fluorescence, and the porphyrin score is calculated as the ratio of porphyrins that emit fluorescence per analysis area. Different types of lotion were applied to the
right and left sides of the face, respectively, and the porphyrin score was analyzed. The porphyrin score before application was used as a standard and compared to the porphyrin score after application.
PERSONAL CARE June 2024
www.personalcaremagazine.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80
