Magnesium Ascorbyl Phosphate Research Articles

A hydrophilic–lipophilic deviation model in formulating microemulsion for topical application

The hydrophilic–lipophilic deviation (HLD) model is firmly established in oil recovery and can be potentially applied in various other fields. In this work, the HLD concept is systematically used to prepare microemulsion for topical application using isopropyl myristate (IPM), squalane, water, mixed nonionic surfactants and magnesium ascorbyl phosphate (MAP). The clear water-in-oil (W/O) microemulsion formed spontaneously and has a consistent submicron droplet size below 30 nm. The microemulsion was characterized by particle size, electrical conductivity, electrophoretic mobility, viscosity and in vitro diffusion. The addition of one part of squalane to three parts of IPM in the oil blend prevented the percolation phenomenon and reduced the electrophoretic mobility of MAP. The inclusion of squalane to IPM in the oil phase reduced the cumulative amount of MAP permeated from the microemulsion, reduced the permeation coefficient of MAP and increased the lag time, reduced the steady-state flux and permeability coefficient as well. The microemulsion provided an alternative approach to encapsulate the water-soluble MAP in an oil matrix as a cosmetic active ingredient for the manufacture of personal care products.

Formulation and Stability Evaluation of Topical Creams Containing Arbutin and Magnesium Ascorbyl Phosphate: Effects of Croda Wax Concentration on Physical Characteristics

Background: Arbutin and magnesium ascorbyl phosphate are widely recognized for their exceptional antioxidant properties, making them valuable ingredients in treating various skin disorders. These compounds are frequently incorporated into skincare products aimed at improving skin health, reducing hyperpigmentation, and providing anti-aging benefits. Objective: The study aimed to develop and evaluate the stability of topical creams containing arbutin and magnesium ascorbyl phosphate, using varying concentrations of Croda Wax as an emulsifying agent, to determine their efficacy and suitability for dermatological applications. Methods: Three formulations of skin lightening cream were prepared, each with different Croda Wax concentrations (2%, 2.5%, and 2.9%). The formulations underwent a water-in-oil emulsion process using a mechanical homogenizer. Physical characteristics such as color, odor, texture, and stability were assessed over 28 days. Stability was further evaluated through phase separation tests at centrifugation speeds of 4000, 4500, and 5000 rpm, and by observing changes under various temperatures and humidity conditions. Results: All formulations exhibited stability with no phase separation. The 2% Croda Wax formulation showed the most favorable results, maintaining a white color with minimal changes over 60 days. pH values ranged from 5.85 to 6.31, indicating stability suitable for skin applications. Conclusion: The formulated creams with arbutin and magnesium ascorbyl phosphate demonstrated excellent physical stability, making them suitable for addressing skin conditions such as hyperpigmentation and inflammation.

Hybrid gelatin-ascorbyl phosphate scaffolds accelerate diabetic wound healing via ROS scavenging, angiogenesis and collagen remodeling

Skin wound healing, particularly diabetic wound healing, is challenging in clinical management. Impaired wound healing is associated with persistent oxidative stress, altered inflammatory responses, unsatisfactory angiogenesis and epithelialization. Magnesium ascorbyl phosphate (MAP), which is an ascorbic acid derivative and active ingredient in cosmetics, has been reported to scavenge reactive oxygen species (ROS), and is considered a potential therapeutic agent for diabetic wounds. Herein, we report a hybrid gelatin-MAP scaffolds that can reduces oxidative stress damage, enhances angiogenesis and collagen remodeling to accelerate diabetic wound repair. Preliminary insights based on network pharmacology indicate that MAP may accelerate wound repair through multiple biological pathways, including extracellular matrix remodeling and anti-apoptosis. In vitro studies showed that the hybrid hydrogel scaffold had suitable mechanical properties, excellent biocompatibility and bioactivity. Further animal experiments demonstrated that the hydrogel accelerated full-thickness wound repair in diabetic mice (repair rate MAP vs Control=91.791±3.306 % vs 62.962±6.758 %) through antioxidant, neuroangiogenesis, collagen remodeling, and up-regulated the expression of the related factors COL-1, CD31, VEGF, and CGRP. Overall, we developed a bioactive hybrid hydrogel encapsulating MAP that synergistically promotes diabetic wound repair through multiple biological effects. This potentially integrated therapeutic scaffold may enrich future surgical approaches for treating diabetic wounds.

Evaluation of Sterify Gel as an Adjunctive Treatment to Scaling and Root Planing in Promoting Healing of Periodontal Pockets: A Split-Mouth Randomized Controlled Trial.

Periodontal disease is a common infectious disease that leads to the destruction of tooth-supporting structures. Current treatments, such as scaling and root planing (SRP), have limitations in deep and complex pockets, and antibiotic use carries the risk of resistance. Sterify Gel, a medical device composed of polyvinyl polymers, hydroxytyrosol, nisin, and magnesium ascorbyl phosphate, offers a new approach to periodontal care. This study aims to evaluate the safety and efficacy of Sterify Gel as an adjunctive treatment to SRP in promoting the healing of periodontal pockets. The study includes 34 patients with moderate to advanced chronic periodontal disease. Randomization assigned one site for SRP alone (control) and the other site for SRP with Sterify Gel (treatment). Periodontal parameters were evaluated at baseline, 1, 2, and 3 months after treatment bacterial contamination was assessed through quantitative PCR at baseline and 3 months after treatment. Statistical analysis was conducted using ANOVA and Wilcoxon test. Treatment with Sterify Gel and SRP demonstrated significant improvements in pocket depth, gingival recession, and clinical attachment level compared with SRP alone. Bleeding and plaque indexes, pain perception, tooth mobility, and furcations showed no significant differences between the two groups. The treatment group showed a reduction in bacterial contamination at 3 months. Sterify Gel in combination with SRP shows the potential for improving periodontal health by promoting healing and reducing periodontal pockets. It may offer benefits in preventing bacterial recolonization and reducing reliance on antibiotics.

Efficacy and Safety of Nicotinamide 10%, Associated with Magnesium Ascorbyl Phosphate 5% and Hyaluronic Acid 5%, Compared to Hydroquinone 4% in Women with Facial Melasma: A Randomized, Double-Blind, Controlled Clinical Trial.

Nicotinamide has demonstrated efficacy in the treatment of melasma. Topical antioxidants and humectants may enhance its performance. Currently, there is no controlled trial on the combination of 10% nicotinamide, 5% magnesium ascorbyl phosphate, and 5% hyaluronic acid, a dermo-cosmetic compound, in comparison to 4% hydroquinone for the treatment of melasma. This study aimed to explore the tolerability and efficacy of the association of the combined product versus hydroquinone. A randomized, double-blind trial involving women with facial melasma was conducted. Participants were instructed to apply the combined product (NIC group) twice daily or 4% hydroquinone for 60 days (HQ group) at night and placebo in the morning. Evaluations were performed at inclusion, after 14 and 60 days of treatment, measuring the modified Melasma Area and Severity Index (mMASI), Melasma Quality of Life Scale (MELASQoL), and colorimetric luminosity. The Global Aesthetic Improvement Scale (GAIS) was assessed by a blinded evaluator. Both interventions led to a progressive improvement in mMASI, MELASQoL, and GAIS, without a difference between them on D14 and D60 (p>0.2). For NIC, the mean reduction (95% CI) in mMASI was 16% (8-24%) on D14 and 32% (23-41%) on D60, while for HQ, it was 10% (7-24%) on D14 and 43% (34-52%) on D60. Reduction in colorimetric luminosity was greater in the HQ group at D60 (p=0.01). No serious side effects were identified. Of the initially included 50 patients, one was lost to follow-up in the HQ group on D60, and one withdrew consent from the NIC group, both unrelated to treatment. The association of 10% nicotinamide, 5% magnesium ascorbyl phosphate, and 5% hyaluronic acid was safe and well-tolerated, although its overall clinical efficacy was numerically inferior to 4% hydroquinone. This regimen can be considered for patients with poor tolerability to hydroquinone. #RBR-4mkfmr8.

New Skin-Relevant Cell Coculture Model With Stratum Corneum-Like Layer.

Two-dimensional (2D) cell culture is an important tool in the discovery of skin-active agents. Fibroblasts and keratinocytes, more rarely fibroblast-keratinocyte cocultures, are usually used for that purpose, where test compounds are added by mixing with the overlaying growth medium. However, such an approach is suboptimal because it lacks the stratum corneum component. The stratum corneum acts as a selective gatekeeper and opposes the intradermal permeation of many compounds that are bioactive when placed in direct contact with cells. One solution is to use reconstituted epidermis, but this approach is costly and time consuming. Here, a model is proposed, where the simplicity and convenience of the 2D cell culture is combined with the advantage of a hydrophobic barrier reminiscent of the skin horny layer. This model was tested with skin-relevant solvents, as well as with "naked" hydrophilic and encapsulated compounds. Cell viability and collagen stimulation were used as readouts. The results showed that the incorporation of a stratum corneum-substitute barrier on top of a 2D cell culture reduced the cytotoxicity of a common cosmetic solvent, dimethyl isosorbide (DMI), in cell culture and modified the bioactivity of the added actives (magnesium ascorbyl phosphate [MAP] and oligomeric proanthocyanidins [OPCs]/levan biopolymer), which became dependent on their ability to penetrate through a lipidic layer. Taken together, these results indicate a better physiological relevance of this cell culture model in workflows aimed at the discovery and analysis of skin-active compounds than conventional 2D systems.

Triple functional magnesium ascorbyl phosphate encapsulated hydrogel: A cosmetic ingredient promotes bone repair via anti-oxidation, calcium uptake and blood vessel remodeling

Bone defect repair involves a synergistic repair process involving the reconstruction of the skeletal system and remodeling of the neurological and vascular systems. However, current strategy/systems are mainly single function/purpose for bone repair. In this study, we propose a strategy that utilizes a simple but multifunctional cosmetic ingredient magnesium ascorbyl phosphate (MAP), for effective in situ cranial defect repair. MAP is loaded into a gelatin methacrylate hydrogel to achieve sustained release and the scaffold supply only phosphorus-containing compounds to promote bone repair without an exogenous supply of Ca2+. Results show that MAP can reduce oxidative stress damage in bone marrow-derived mesenchymal stem cells (BMSCs) by scavenging reactive oxygen species and promoting Ca2+ uptake to accelerate the mineralization of BMSCs in vitro. In addition, the pro-angiogenic and ERK/AKT signaling pathway activation abilities of MAP accelerate the biological process of bone defect repair. Micro-CT result reveal a greater repair rate in the 8-week MAP group (32.74 ± 0.62%) than in the control group (7.08 ± 0.29%). This study suggests that inorganic-phosphorus-based small-molecule delivery and calcium-free strategies have considerable potential in bone defect repair.

Magnesium Ascorbyl Phosphate Promotes Bone Formation Via CaMKII Signaling.

Dysregulation of bone homeostasis is closely related to the pathogenesis of osteoporosis. Suppressing bone resorption by osteoclasts to attenuate bone loss has been widely investigated, but far less effort has been poured toward promoting bone formation by osteoblasts. Here, we aimed to explore magnesium ascorbyl phosphate (MAP), a hydrophilic and stable ascorbic acid derivative, as a potential treatment option for bone loss disorder by boosting osteoblastogenesis and bone formation. We found that MAP could promote the proliferation and osteoblastic differentiation of human skeletal stem and progenitor cells (SSPCs) in vitro. Moreover, MAP supplementation by gavage could alleviate bone loss and accelerate bone defect healing through promoting bone formation. Mechanistically, we identified calcium/calmodulin-dependent serine/threonine kinase IIα (CaMKIIα) as the target of MAP, which was found to be directly bound and activated by MAP, then with a concomitant activation in the phosphorylation of ERK1/2 (extracellular regulated kinase 1/2) and CREB (cAMP-response element binding protein) as well as an elevation of C-FOS expression. Further, blocking CaMKII signaling notably abolished these effects of MAP on SSPCs and bone remodeling. Taken together, our data indicated that MAP played an important role in enhancing bone formation through the activation of CaMKII/ERK1/2/CREB/C-FOS signaling pathway and may be used as a novel therapeutic option for bone loss disorders such as osteoporosis. © 2023 American Society for Bone and Mineral Research (ASBMR).

A turn-on chemiluminescent assay for alkaline phosphatase using two-dimensional Fe-centered metal-organic frameworks as the signaling probe.

Alkaline phosphatase (ALP) is an essential enzyme involved in cell phosphorus metabolism. Developing sensitive and accurate ALP quantitative assays is significant. In this study, a turn-on chemiluminescence (CL) analysis platform for the detection of ALP activity in human serum was established based on two-dimensional (2D) Fe-centered metal-organic frameworks with 1,3,5-benzene tricarboxylic acid as ligands (denoted as 2D Fe-BTC). The 2D Fe-BTC as the signaling probe reacts with ascorbic acid forming reduced Fe-BTC which catalyzes the luminol CL reaction producing a strong CL signal. The 2D Fe-BTC-based luminol CL reaction exhibited good CL responses when the concentration of ascorbic acid was in the range of 5-500nM. By employing magnesium ascorbyl phosphate (MAP) as the substrate which can be hydrolyzed by ALP to generate ascorbic acid, a turn-on CL assay for the detection of ALP was established. Under optimal conditions, as low as 0.00046UL-1 of ALP could be sensitively detected with a linear range of 0.001-0.1UL-1. ALP in human serum can be detected after a simple dilution process without any other pretreatment.

Stabilization and strengthening of chromium(VI)-contaminated soil via magnesium ascorbyl phosphate (MAP) and phytase addition

Cr(VI) contamination of soil threatens the environment and reduces soil strength. Therefore, both Cr(VI) stabilization and soil reinforcement should be considered in site remediation for future construction. This study investigated a biochemical treatment process using magnesium ascorbyl phosphate (MAP) and phytase. MAP was hydrolyzed via phytase catalysis to produce ascorbic acid (AA) and MgHPO4·3H2O precipitation. The AA reduced Cr(VI) into low-toxic Cr(III), which precipitated as Cr(OH)3 and CrPO4. More than 90% of the 500 mg/kg Cr(VI) in soil was reduced by 5% MAP (wt% of soil) and 1% phytase (vol/vol of soil water) doses at the geotechnically optimal soil moisture content of 16.8%. The MgHPO4·3H2O precipitates filled soil pores and enhanced the unconfined compression strength of treated soil by more than two times. This research reports a novel and practical enzymatically induced phosphate precipitation process for the remediation of Cr(VI)-contaminated soil.

Magnesium ascorbyl phosphate vesicular carriers for topical delivery; preparation, in-vitro and ex-vivo evaluation, factorial optimization and clinical assessment in melasma patients

Ascorbic acid (vitamin C) is an antioxidant that is widely used in cosmetics in skincare products. Due to the excessive low stability of ascorbic acid in cosmetic formulations, the stabilized ascorbic acid derivative, magnesium ascorbyl phosphate (MAP) was formulated as vesicular carriers; ethosomes and niosomes. The aim was to deliver MAP at the intended site of action, the skin, for sufficient time with enhanced permeation to get an effective response. Ethosomes were formulated using a full 32 factorial design to study ethanol and phospholipid concentration effect on ethosomes properties. Niosomes were formulated using 23 factorial designs to study the effect of surfactant type, surfactant concentration and cholesterol concentration on niosomes properties. The prepared formulations were evaluated for their Entrapment efficiency, particle size, polydispersity index, zeta potential and % drug permeated. The optimized ethosomal and niosomal formulations were incorporated into carbopol gel and evaluated for their permeation, skin retention and stability. A comparative split-face clinical study was done between the ethosomal and niosomal formulations for melasma treatment using Antera 3 D® camera. The optimized ethosomal and niosomal gels showed comparable controlled permeation and higher skin retention over their ethosomes and niosomes formulations respectively. Magnesium ascorbyl phosphate ethosomal gel showed clinically and statistically significant melanin level decrease after one month while MAP niosomal gel showed clinically and statistically significant melanin level decrease after six months. A combination of MAP ethosomes and niosomes could be promising skincare formulations for melasma and hyperpigmentation short and long-term treatment.

Oxidative stress in the skin: Impact and related protection.

Skin, our first interface to the external environment, is subjected to oxidative stress caused by a variety of factors such as solar ultraviolet, infrared and visible light, environmental pollution, including ozone and particulate matters, and psychological stress. Excessive reactive species, including reactive oxygen species and reactive nitrogen species, exacerbate skin pigmentation and aging, which further lead to skin tone unevenness, pigmentary disorder, skin roughness and wrinkles. Besides these, skin microbiota are also a very important factor ensuring the proper functions of skin. While environmental factors such as UV and pollutants impact skin microbiota compositions, skin dysbiosis results in various skin conditions. In this review, we summarize the generation of oxidative stress from exogenous and endogenous sources. We further introduce current knowledge on the possible roles of oxidative stress in skin pigmentation and aging, specifically with emphasis on oxidative stress and skin pigmentation. Meanwhile, we summarize the science and rationale of using three well-known antioxidants, namely vitamin C, resveratrol and ferulic acid, in the treatment of hyperpigmentation. Finally, we discuss the strategy for preventing oxidative stress-induced skin pigmentation and aging.

Rapid identification of magnesium ascorbyl phosphate utilizing phosphatase through a chromogenic change-coupled activity assay.

In this study, we report a chromogenic reaction between magnesium ascorbyl phosphate (MAP) and ferric chloride to generate a Brown-Red clathrate, while the Treated MAP by phosphatases forms Colorless (BRTC) product with ferric chloride. The BRTC was indicative of phosphatase activity-mediated excision of phosphorous group from MAP and utilized to screen phosphatases from bacterial cell lysates. From ten tested strains, BRTC was observed in the cell lysate of Salmonella enterica subsp. enterica serovar Cerro 87. BRTC was again employed to track phosphatase activity of the resuspensions of the ammonium sulfate graded precipitations of the cell lysate. Two phosphatases, PhoN and YcdX, were identified by LC-MS/MS analysis in the protein fraction giving most obvious BRTC phenotype and validated by examination of in vitro activity of the purified proteins. KEY POINTS: • BRTC is labelling-free, naked-eye visible, and independent of any facilities. • BRTC can directly screen phosphatases from microbial cell lysates. • Using BRTC system, two phosphatases were identified in Salmonella enterica subsp. enterica serovar Cerro 87.

Magnesium ascorbyl phosphate loaded in dissolving stiff microneedles containing cellulose nanofiber

Magnesium ascorbyl phosphate (MAP) was loaded in a dissolving microneedles (MNs) composed of cellulose nanofiber (CNF), hyaluronic acid, collagen, and trehalose for its effective dermal delivery. MN matrices whose MAP content was 7.5, 14, and 24.5% were fabricated by casting mixture solutions containing MAP on silicone molds, centrifuging and drying them at room temperature. On the SEM micrographs of MN matrices, a 15 × 15 array of pyramidal needles (300 μm in base width and 600 μm in height) were observed and the polymeric needles were close to the pyramidal holes of the mold and the metallic needles of a master in terms of the shape and the dimension. The stiffness of the needles markedly increased with little decrease in failure load when MAP was included in the MN matrix as low as 7.5%. The stiffness of the needle appreciably decreased with a small decrease in failure load at a higher MAP content (e.g. 14 and 24.5%). Even though the high inclusion of MAP in the MN matrices (e.g. 14 and 24.5%) deteriorated the stiffness of needles, the stiffness was sufficient for skin perforation regardless of MAP content. The cumulative amount of MAP permeated though skin was proportional to the MAP content of a microneedle matrix. Not only the needles but also the base of a MN matrix seemed to act as a depot for the skin permeation of MAP, leading to a long-lasting permeation. A high content of MAP was unfavorable in terms of in vitro cellular toxicity. Regardless of MAP content, no severe toxicity was observed if the concentration of the constituents of the MN matrices was kept below 100 μl/ml.

Simultaneous Determination of Five Whitening Agents by Ion-Pair Reversed-Phase High Performance Liquid Chro- matography

ABSTRACT A gradient ion-air reversed-phase high performance liquid chromatography method was developed for simultaneous determination of 5 whitening agents (ascorbic acid (AA), magnesium ascorbyl phosphate (MAP), kojic acid (KA), arbutin (ART) and hydroquinone (HQ)). The gradient elution was performed using Inertsil ODS-3V column (250 × 4.6 mm, 5 μm). The analytes were detected by ultraviolet light absorption at the wavelength of 270 nm, the flow rate was set at 1.0 mL/min, and the sample injection volume was 10 μL. The buffer solution contains 50 mM sodium phosphate monobasic dihydrate and 2 mM n-hexadecyltrimethyl ammonium bromide at pH 4.5. The precision of the proposed method, expressed as relative standard deviation (RSD) (%), was determined by the analysis of each compound. The RSD range was from 0.23 to 0.55%. The calibration curves were found to be linear in 8.12-40.6 μg/mL (KA), 12.44-62.20 μg/mL (ART), 8.28-41.40 μg/mL (HQ), 8.16-40.80 μg/mL (MAP) and 4.25- 1.80 μg/mL (AA). The correlation coefficient of linear regression analysis (R2) was within the range of 0.9968 - 0.9997. The analytical results were satisfied for these 5 whitening agents. The recoveries ranging from 96.97% to 101.22% for lotion, and from 97.17 to 100.80% for cream, were obtained at both low and high concentrations. The proposed method is suitable for routine analysis of the 5 whitening agents in commercial cosmetic products, or examined the allowable amount of whitening agents for the Department of Health.

Effect of magnesium ascorbyl phosphate on collagen stabilization for wound healing application

Wound healing is a complex process which requires appropriate structural support for restoration of tissue continuity and function. Collagen can act as a template for cellular activities but poor physico-chemical properties necessitates the stabilization of collagen without impairing its structure and function. This study investigates the effect of magnesium ascorbyl phosphate (MAP) on collagen with reference to physico-chemical properties. Incorporation of MAP enhanced the rate of collagen fibrillation signifying increased interaction at reduced time interval. MAP did not induce any changes in the secondary structure of collagen while there was an increase in shear viscosity with increase in shear stress at different shear rate. MAP stabilized collagen film exhibited higher denaturation temperature and showed an increase in Young's Modulus when compared with that of collagen film. In vivo studies showed complete wound closure on day 16 in case of stabilized collagen film. Mechanical properties of healed skin revealed that MAP collagen film treated rat skin completely regained its properties similar to that of normal skin thereby making them a potential candidate for wound healing application.

Simultaneous voltammetric determination of ascorbic acid and its derivatives in cosmetics using epoxy-carbon composite electrodes

We used a voltammetric method to determine the levels of ascorbic acid (AA) and two AA derivatives (magnesium ascorbyl phosphate (MAP) and ascorbyl palimitate (AP)) in cosmetic products. These compounds are believed to affect the process of skin aging and are widely used in skin care products. An electrode composed of an epoxy resin and graphite powder can be easily fabricated. We studied the effects of solutions' pH and different supporting electrolytes on the performance of a carbon-epoxy electrode which we used as a working electrode to take voltammetric measurements that would quantify the levels of AA, MAP and AP in various cosmetic products effectively. In the voltammogram, anodic peak potentials of AA, MAP and AP were obtained at about 0.35 ± 0.07, 0.81 ± 0.11, and 0.23 ± 0.03 volts in various pH and different supporting electrolytes respectively. Linearity of peaks from plots of current vs. concentration (correlation coefficient r2 > 0.997) was over the range of 10-300 μg/mL for all analytes. The limits of detection (LOD) for AA, AMP and AP were lower than 0.17, 0.46 and 0.09 μg/mL respectively. For the three analytes in cosmetic formulations, the relative standard deviations were below 6.3%, and the range of recovery ratio ranged from 92.2 to 104.5%. Various compounds coexisting in the formulations that were potential sources of organic interferences in voltammetric analysis were explored. Ascorbic acid oxidizes easily to dehydroascorbic acid, but its derivatives are relatively stable. Material instability could result in a significant error in the analytical method. Different approaches were used to inhibit ascorbic acid degradation, and purge of oxygen from the analyzed solution with nitrogen was found to be the most effective method.

Simultaneous determination of magnesium ascorbyl phosphate, ascorbyl glucoside, kojic acid, arbutin and hydroquinone in skin whitening cosmetics by HPLC

A high performance liquid chromatographic method was developed for simultaneous determination of 5 whitening ingredients: magnesium ascorbyl phosphate, ascorbyl glucoside, kojic acid, arbutin and hydroquinone decomposed from arbutin in cosmetics. Samples were extracted with 0.05 M KH2PO4 buffer solution (pH 2.5) and analyzed using a Cosmosil 5 C18-AR-II column. A mixture of 0.05 M KH2PO4 buffer solution (pH 2.5) and methanol (99:1, v/v) was used as mobile phase. The UV detector was set at 280 nm. Pyridoxine was used as an internal standard. The related coefficients, R2, of regression equations of the 5 standard curves were 0.9998-1.0000. The relative standard deviations of the 5 ingredients for intraday and interday analysis were less than 2.4%. The average recoveries of these 5 ingredients spiked in sample ranged from 93.5% to 103.3%. The relative standard deviations of average recoveries were less than 1.3%. The limits of quantitation in cosmetics were 80.0, 20.0, 3.0, 15.0 and 10.0 μg/mL for magnesium ascorbyl phosphate, ascorbyl glucoside, kojic acid, arbutin and hydroquinone, respectively.

694 An epidermal model containing melanocytes for skin pigmentation and lightening studies

Considerable interest exists in evaluating raw materials and/or skin care formulations which cause lightening of the skin. These products are utilized to modulate one’s natural skin color or to combat skin pigmentation disorders such as melasma, dark spots, solar lentigo, and other hyperpigmentation lesions. To aid in the development and testing of such products, we have developed a skin whitening protocol using the epidermal skin model, MelanoDerm™, to evaluate both raw materials and skin lightening formulations. MelanoDerm is a highly differentiated, three-dimensional tissue culture model of human epidermis that contains normal human melanocytes (NHM) and keratinocytes (NHK). Epidermal tissues have been produced containing NHM of varying skin phototypes which follow the pigmentation level of the donor tissue, i.e. black > Asian > Caucasian. For lightening studies, tissues were treated topically three times a week over a two to three week period to mimic consumer application. Several over-the-counter skin lightening products were evaluated in cultures containing NHM from black and Asian donors. Over the treatment period, negative control cultures became increasingly pigmented with retention of normal epithelial morphology. In contrast, tissues treated topically with cosmetic skin lightening agents containing tyrosinase inhibitors such as kojic acid and magnesium ascorbyl phosphate remained lighter than the control cultures. The skin lightening effect on treated tissues was quantitatively evaluated for melanin content using a Solvable melanin assay and for skin brightness (L* value) using a hand-held spectrometer. Treated tissues showed significant changes in overall melanin content and brightness compared to control tissues. These results suggest that this model can provide valuable in vitro data for screening raw materials prior to the commencement of costly clinical trials and that it will be useful to study melanogenesis, skin lightening, and other pigmentation phenomena of the skin.

Gold Nanocluster-catalyzed Luminol Chemiluminescent Sensing Method for Sensitive and Selective Detection of Alkaline Phosphatase.

A sensitive sensing method was developed for the determination of alkaline phosphatase (ALP) activity based on gold nanocluster (Au NC)-catalyzed luminol-H2O2 chemiluminescent (CL) reaction. The CL signal of luminol-H2O2-Au NCs can be quenched by ascorbic acid, which was the product of magnesium ascorbyl phosphate (MAP) hydrolysis reaction catalyzed by ALP. The proposed sensing platform showed convenient, sensitive and selective detection of ALP in the range of 0.0027 - 1.3890 U L-1, with the detection limit of 0.0026 U L-1. The broad detection linear range and ultra-high sensitivity were inherited from the efficient free radical scavenging capability of ascorbic acid on the luminol-H2O2-Au NCs CL reaction. The CL sensing platform was applied to the detection of ALP activity in serum samples. We believe that this sensing platform is a universal CL strategy for ALP detection because ascorbic acid is an efficient CL quencher for many CL reactions.