SKINCARE PRODUCT AND METHOD OF PREPARATION THEREOF

Abstract

The core active components of the present composition, termed as de-ironizing inducers (DII), has a reducing agent and a precipitating agent. Molar ratios of the reducing agent with the precipitating agent range from 1:3-6 and the core components in the skincare product range from 0.1% to 10% w/w. The pH value of the skincare product is between 6.6 and 7.4. The skin care products can safely and effectively remove iron in the skin, which has been shown to accelerate skin natural aging and photoaging. The core components can also be used in combination with conventional skincare product compounds to achieve better anti-aging effects.

Claims

1. A skincare product comprising: a reducing agent selected from vitamin C, vitamin E, glutathione, vitamin A, vitamin D, and their derivatives; and a precipitating agent selected from calcium carbonate, pearl powder, magnesium carbonate, barium carbonate, calcium phosphate, magnesium phosphate, barium phosphate, calcium silicate, calcium molybdate, calcium tungstate, magnesium silicate, magnesium selenite, barium oxalate, barium molybdate, barium manganate, barium selenate, beryllium carbonate, beryllium phosphate, beryllium silicate, strontium carbonate, strontium phosphate, strontium silicate, strontium molybdate, strontium tungstate, strontium selenate, and barium silicate, wherein a molar ratio of the reducing agent to the precipitating agent is in a range of 1:3-1:6, wherein the reducing agent and the precipitating agent together represent 0.1%-10% w/w of the skincare product; and wherein a pH the skincare product is in a range of 5 to 8.

2. The skincare product according to claim 1, wherein the molar ratio of the reducing agent to the precipitating agent is 1:5.

3. The skincare product according to claim 1, wherein the reducing agent and the precipitating agent together represent 0.5% (w/w) of the skincare product.

4. The skincare product according to claim 1, wherein the pH of the skin care product is 7.

5. The skincare product according to claim 1, wherein a particle diameter of the precipitating agent is about 0.3 micron to about 1 micron.

6. A method to prepare the skincare product according to claim 1, comprising the steps of: a.) grinding a precipitating agent to a particle size of 1-5 microns; b) suspending the particles of the precipitating agent in deionized and nitrogen-saturated water; c) adding a reducing agent into the suspension of the precipitating agent, wherein the reducing agent is added to precipitating agent such that a molar ratio of the reducing agent to the precipitating agent is in the range of 1:3 to 1:6; and d) adjusting a pH of the skincare product to about 5 to 8.

7. The method according to claim 6, wherein the particle size in step a) is 1 to 3 micron.

8. The method according to claim 6, further comprising the step of: stirring speed the precipitating agent in step b) at 200 to 500 rotation per minute.

9. The method according to claim 6, wherein pH is 7.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1. Concurrent but inverse changes of ferritin versus estrogen during menopausal transition.

[0028] FIG. 2. Differences in levels of ferritin between skin biopsy samples of pre- and post-menopausal women.

[0029] FIG. 3. Effects of UVA and iron on MMP-1 activities in primary human dermal fibroblasts.

[0030] FIG. 4. Reducing effects of vitamin C on iron from ferritin.

[0031] FIG. 5. Precipitating effects of calcium carbonate on iron.

[0032] FIG. 6. Inhibition of ferritin formation by the core components of the invention.

[0033] FIG. 7. Inhibition of lipid peroxidation by the core components of the invention.

[0034] FIG. 8. Analyses of particle size of calcium carbonate with or without vitamin C treatment.

[0035] FIG. 9. Comparison of penetrations of submicron and micron particles of calcium carbonate into the three-dimensional skin model.

[0036] FIG. 10. Results from clinical trial questionnaire on satisfaction rate after using the skincare product of the present invention.

[0037] FIG. 11. Skin improvements after using the skincare product of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0038] In conjunction with the drawings and the embodiments, the present invention is further explained in detail as below:

Embodiment 1

[0039] Changes in estrogen and ferritin levels during menopausal transition: Serum levels of 1713-estradiol (E2) were converted to % of peak value at 500 pg/mL serum at age 25. Levels of ferritin were expressed as ng/mL serum. E2 data as a function of age were obtained from website http://www.drlam.com/A3R brief in doc format/Estrogen Dominance. cfm. Ferritin data were obtained from the Third National Health and Nutrition Examination Survey (NHANES III) in the United States (FIG. 1).

[0040] Human studies: Studies were performed after informed consent was obtained according to an approval from the local Institutional Review Board. Human skin 3 mm punch biopsy samples were obtained from six pre- and six post-menopausal women by punching the upper, inner left and right arms. Skin weights ranged from 3 to 50 mg. After grinding with a Dremel mini-Tissue Homogenizer in 400 l M-PER lysis buffer in the presence of a protein inhibitor cocktail (Pierce Biotechnology Inc., Rockford, Ill.), protein extracts were collected after removing debris by centrifugation. The concentrations of total protein extracted from the skin samples were determined by bicinchoninic acid (BCA) assay. The remaining protein extracts were used for measurements of ferritin. Two data points (left and right arm) per subject were presented in the study. Results were expressed as ng ferritin per mg of total protein and are presented in FIG. 2. Mean age of post-menopausal women was 58.81.3 year old (n=5) and mean level of ferritin in the post-menopausal skin was 542.4 ng/mg protein. Mean age of pre-menopausal women was 41.61.7 year old (n=6) and mean level of ferritin in pre-menopausal skin was 381.6 ng/mg protein. It is noteworthy that one outlier from post-menopausal skin with a left arm ferritin of 2,360.2 ng/mg protein and a right arm ferritin of 989.0 ng/mg protein was excluded in the analyses. Otherwise, the difference would be even more significant (FIG. 2).

[0041] Cell culture and UVA exposure: Primary human dermal fibroblasts were seeded in 6-well plates and starved in 0.1% fetal bovine serum (FBS)-containing Dulbecco's Modified Eagle Medium (DMEM). According to FIG. 1, two cell culture conditions were developed with the low estrogen and high iron mimicking postmenopausal women and high estrogen and low iron simulating premenopausal women. In premenopausal condition (Pre-), level of 17-estradiol (E2) in the cell culture media is 500 ng/ml and that of apo-transferrin (Tf, without iron) is 5 g/ml. In postmenopausal condition (Post-), level of ferritin is 20 ng/ml and that of holo-Tf (iron is 100% saturated in the two binding sites of Tf) is 5 g/ml. After overnight starving, fibroblasts grown under either the control, Pre-, or Post-conditions were exposed to UVA at 50 kJ/m.sup.2. Media were collected 24 h later for measurements of matrix metalloproteinase-1 (MMP-1) activities. MMP-1 activities were measured by Forster resonance energy transfer (FRET) assay following the Manufacturer's protocol (AnaSpec, San Jose, Calif.). Briefly, 100 l sample or 100 l standard were added in the plate pre-coated with anti-MMP-1 antibody for 2 h. After washing, MMP fluorogenic substrate, 5-FAM/QXL 520 FRET peptide, were added and cultured for 16 h at room temperature. The fluorescence is measured at Ex/Em=490 nm/520 nm upon MMP-1-induced cleavage of the FRET substrate. Results show that there were no differences in background levels of MMP-1 in fibroblasts grown under Pre or Post-menopausal conditions. However, UVA significantly induced MMP-1 activities in primary human dermal fibroblasts grown under Post-condition as compared to fibroblasts grown under the control or Pre-conditions (FIG. 3).

[0042] Reduction of iron from ferritin by vitamin C: Ferritin at a concentration of 1 mg/ml was incubated with various concentrations of vitamin C (0-500 M). After one hour incubation, the solutions were filtered using a membrane with a molecular weight cutoff of 5,000 Dalton (Millipore). Levels of iron in the filtrates were measured by Ferrozine (Sigma, St. Louis, Mo.), which forms a stable magenta-colored complex (Fe.sup.2+-ferrozine) with a maximum absorption at 560 nm. In brief, 30 l sample was added to 135 l buffer. After 10 min incubation at 37 C., the absorbance was measured at 560 nm using a UVvisible microplate reader (SpectraMax Plus, Molecular Devices, Sunnyvale, Calif.). Then, 5 l iron chromogenic agent (ferrozine) was added and after 15 min incubation, the absorbance was measured again at 560 nm. The difference in absorbance was used to calculate iron concentration after comparing to the iron standard curve. To determine whether iron is completely released from ferritin, atomic absorption (AA) was used to measure total iron in ferritin. Results show that high concentration of vitamin C is effective in releasing iron from ferritin. Atomic absorption (AA) confirmed that all iron in ferritin is released after vitamin C reduction (FIG. 4).

[0043] Precipitation of iron by calcium carbonate: Iron was added to extracellular matrix, followed by the addition of different concentrations of calcium carbonate (0-10%) (FIG. 5). After various time periods of incubation, a small part of the mixture was filtered using a membrane with a molecular weight cutoff of 5,000 Dalton as previously described in FIG. 4. Levels of iron in the filtrates were determined by Ferrozine. Results show that calcium carbonate can effectively precipitate iron in the cellular matrix.

[0044] Inhibition of ferritin formation by the core components: Primary normal human epidermal keratinocytes (NHEK) were seeded in 6-well plates. The cells were pretreated with 50 M ferrous sulfate for 4 h, followed by a mixture of vitamin C and calcium carbonate at 10 g/cm.sup.2 for 20 h. After washing, the cells were collected and the proteins were extracted in lysis buffer. After determining protein concentration, a small portion of the protein was used for the measurement of ferritin. Results show that a mixture of vitamin C and calcium carbonate can effectively decrease ferrous sulfate-induced ferritin formation in NHEK (FIG. 6).

[0045] Inhibition of lipid peroxidation by the core components: NHEK cells were treated as described in FIG. 6. After centrifugation, cell debris was collected for measurements of lipid peroxidation using thiobarbituric acid assay. Results show that a mixture of vitamin C and calcium carbonate can effectively inhibit ferrous sulfate-induced lipid peroxidation in primary NHEK cells (FIG. 7).

Embodiment 2

[0046] Suspend calcium carbonate with particles size of approximate 2 m at 100 mg per ml in deionized and nitrogen-saturated water. [0047] 1. Grind calcium carbonate to a particle size of approximately 2 m; (2) Suspend calcium carbonate at 100 mg per ml in deionized and nitrogen-saturated water in order to avoid the oxidation of the mixture; stir slowly at 200-500 rounds per minute so that small particles float and the larger particles stay at the bottom; (3) At room temperature, add slowly 0.2 ml of 176 mg per ml of vitamin C to the bottom of the calcium carbonate suspension; use the acidity of vitamin C to reduce micron calcium carbonate particles to sub-micron particles; at the end of the reaction when there is no more bubbles, gently heat the reaction mixture to 45 C. and reduce the volume by about 50% under vacuum, and the molar ratio of the vitamin C to calcium carbonate is 1:5; (4) Add the core components, a mixture of vitamin C and calcium carbonate, into the matrix at 5% (w/w), and adjust PH to 7.

Embodiment 3

[0048] 1. Grind calcium carbonate to a particle size of approximately 2 m; (2) Suspend calcium carbonate at 100 mg per ml in deionized and nitrogen-saturated water in order to avoid the oxidation of the mixture; stir slowly at 200-500 rounds per minute so that small particles float and the larger particles stay at the bottom; (3) At room temperature, add slowly 0.33 ml of 176 mg per ml of vitamin C to the bottom of the calcium carbonate suspension; use the acidity of vitamin C to reduce micron calcium carbonate particles to sub-micron particles; at the end of the reaction when there is no bubbles, gently heat the reaction mixture to 45 C. and reduce the volume by about 50% under vacuum, and the molar ratio of the vitamin C to calcium carbonate is 1:3; (4) Add the core components, a mixture of vitamin C and calcium carbonate, into the matrix at 10% (w/w), and adjust PH to 7.

Embodiment 4

[0049] EFT 400 skin models were obtained from MatTek (Ashland, Mass.). Experiments were divided into two groups. One group is treated with 10 pg/cm.sup.2 micron particles of calcium carbonate for 24 h; the other group is treated with 10 pg/cm.sup.2 submicron particles of calcium carbonate for 24 h. After treatment, histological examination was carried out by hematoxylin and eosin staining and calcium levels penetrated into the skin were determined by alizarin staining, respectively. Results show that submicron calcium carbonate particles as prepared by the present invention are more readily that micron particles to enter the skin (FIG. 9).

Embodiment 5

[0050] Clinical trial participants used the skincare product of the present invention twice a day, once in the morning and once in the evening. After one month, participants were asked to conduct a survey of satisfaction after they used the product. Survey results show that satisfaction rate with reconstruction and stimulation of new collagen and formation of elastin is 93% (FIG. 10).

Embodiment 6

[0051] Clinical trial participants were required to take pictures at the corner of the right eye (canthus) before using the product of this invention, and then 3 months after continuous use of the product. Results show that canthus wrinkles after using the product of the invention is significantly reduced, highly improving skin appearance (FIG. 11).