Quantitative analysis of fragrance allergens in various matrixes of cosmetics by liquid-liquid extraction and GC-MS.

Fragrances are the most common chemicals in cosmetics to which people expose every day. However, the unwanted allergic reactions such as contact dermatitis caused by direct contact with fragrances may happen. In Directive 2003/15/EC of the EU, cosmetic product containing one or more of 26 fragrance allergens must be declared on the package label. In addition, commission regulation (EU) 2017/1410 amending Annexes II and III of cosmetic regulation 1223/2009 restricted fragrance chemical of methyl eugenol, and prohibited Lyral, atranol, chloroatranol to be used in cosmetic. In this study, an efficient and sensitive GC-MS method for 3 banned fragrances, 26 fragrance allergens along with restricted methyl eugenol in cosmetics was established. Sample preparation by liquid-liquid extraction was developed by testing various solvent systems to simplify traditional complex extraction methodologies. Validation of the proposed method showed good linearities in a wide concentration ranges of 0.1-10 µg/mL. The intra-day and inter-day recoveries were between 84.4 and 119% with coefficient of variation (CV) below 13.5%. The limit of quantifications (LOQs) of 27 fragrance allergens were in the range of 2-20 µg/g. A surveillance study consisted with 82 cosmetics was conducted, among which 31 products claimed fragrance-free. The results showed some fragrance-free claims were false. In the other hand, there were seven cosmetics labeled containing Lyral, but only four were detected. The top fragrance allergens detected in the samples were linalool, limonene, and geraniol. The analysis of fragrance allergens in cosmetics indicated that potential contact allergy related to these products should be considered, even though some fragrance allergens were from natural extracts, such as oak moss absolute.

Determination of cannabinoids in hemp oil based cosmetic products by LC-tandem MS.

Cosmetic products containing hemp seed oil as permitted raw materials required the specific compound delta-9-tetrahydrocannabinol (THC) below 10 µg/g. THC was the main psychoactive constituent of cannabis. Since hemp seed oil became an increasingly popular ingredient in cosmetics over the last few years, an efficient and reliable analytical method for THC and other cannabinoids in cannabis-infused cosmetic products was in need. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN) in hemp seed oil based cosmetic products was developed. Method validation was performed by fertilizing blank samples with analytes and internal standards (THC-d3, CBD-d3, and CBN-d3). Chromatographic method utilized a Xbridge BEH Shield RP18 column with gradient elution containing 10 mM ammonium formate in water and methanol provided successful separation of THC, CBD, and CBN in cosmetic matrix. The combination of MS detection in positive electrospray ionization (ESI) and multiple reaction monitoring (MRM) mode offered rapid run time 13 minutes with limit of quantification (LOQ) of 0.05 µg/g. The intra- and inter-day recoveries were 79.23-114.04% and 83.55-111.61% with spiking levels ranged between 0.05 µg/g and 0.5 µg/g, respectively. Surveillance results of 90 cosmetic products showed 22, 34, and 5 products containing THC (0.06-1777 µg/g), CBD (0.47-37217 µg/g), and CBN (2.2-25.2 µg/g), respectively. This validated method offered accurate, reliable, and fast way for the determination of drug contaminations including THC, CBD, and CBN in cosmetics. The surveillance results for commercial cosmetic products purchased in Taiwan between 2018-2020 provided valuable background references for THC, CBD, and CBN in hemp seed oil based cosmetic products, and could be used for administration purpose.

Comparison of flexural properties and cytotoxicity of interim materials printed from mono-LCD and DLP 3D printers.

STATEMENT OF PROBLEM: Because few 3D-printing resins have been specifically developed for liquid crystal display (LCD) 3D printers, mono-LCD users may use digital light processing (DLP) 3D-printing resins. However, the suitability of these resins requires evaluation. PURPOSE: The purpose of this in vitro study was to evaluate whether 3D-printing resins designed for DLP 3D printers can be used successfully in a mono-LCD 3D printer. MATERIAL AND METHODS: 3D printers based on photopolymerization and 3D-printing resin for interim restorations were used in this study. Enlighten AA temp and NextDent C&B MFH were printed from both the MiiCraft Ultra 125 and Phrozen Sonic printers, followed by postpolymerization by using the FormCure and PhrozenCure units for different times. The flexural strength and cytotoxicity of the specimens were evaluated. RESULTS: After postpolymerization treatment, the flexural strength of Enlighten AA temp and NextDent C&B MFH from both 3D printers was over the 50-MPa minimal requirement for the flexural strength of interim resins specified in the International Standards Organization (ISO) 10477 standard. With 15 minutes of FormCure and 1 minute of PhrozenCure postpolymerization, 4 material-printer combinations reached nearly 100% in cell viability. CONCLUSIONS: Interim resins designed for DLP 3D printers can be successfully used in mono-LCD 3D printers if the printed specimens are postpolymerized in a more powerful postpolymerization unit or in a less powerful postpolymerization unit for a longer time.

Determination of polycyclic aromatic hydrocarbons (PAHs) in cosmetic products by gas chromatography-tandem mass spectrometry.

A gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) method is developed to determine 18 representative polycyclic aromatic hydrocarbons (PAHs) in cosmetics, including Benzo[a]pyrene (BaP) and others. The method offers high sensitivity and selectivity under selected reaction monitoring (SRM) mode to satisfy the requirements of both quantitation and qualitation. The extraction solvent system used in this study is acetone/hexane 1:1 (v/v) and other purification procedure is unnecessary. The linearities of 18 PAHs are validated in different concentration in the range of 0.25-20 ng/mL individually with coefficient correlation (r) higher than 0.996. The recoveries for spiking 3 different concentrations are from 87.40% to 120.44% for 18 PAHs and the coefficient of variation (CV) are below 12.32%. Limit of quantification (LOQ) of 18 PAHs is in the range of 0.05-0.2 mg/kg. A matrix enhancement effect is observed and can be compensated with deuterated internal standard. The method has been successfully applied to 73 samples, over 40 of them are lipsticks. The results show none of the samples detect Benzo[a]pyrene (BaP) and Dibenzo[a,h]anthracene (DBA), both are classified as the most carcinogenic. 8 PAHs are detected and the average value between 0.08 and 0.27 mg/kg. This study offers a sensitive and simple method to analyze 18 representative PAHs successfully and can be applied to cosmetic products and raw materials.

Anatomical Thin Titanium Mesh Plate Structural Optimization for Zygomatic-Maxillary Complex Fracture under Fatigue Testing.

This study performs a structural optimization of anatomical thin titanium mesh (ATTM) plate and optimal designed ATTM plate fabricated using additive manufacturing (AM) to verify its stabilization under fatigue testing. Finite element (FE) analysis was used to simulate the structural bending resistance of a regular ATTM plate. The Taguchi method was employed to identify the significance of each design factor in controlling the deflection and determine an optimal combination of designed factors. The optimal designed ATTM plate with patient-matched facial contour was fabricated using AM and applied to a ZMC comminuted fracture to evaluate the resting maxillary micromotion/strain under fatigue testing. The Taguchi analysis found that the ATTM plate required a designed internal hole distance to be 0.9 mm, internal hole diameter to be 1 mm, plate thickness to be 0.8 mm, and plate height to be 10 mm. The designed plate thickness factor primarily dominated the bending resistance up to 78% importance. The averaged micromotion (displacement) and strain of the maxillary bone showed that ZMC fracture fixation using the miniplate was significantly higher than those using the AM optimal designed ATTM plate. This study concluded that the optimal designed ATTM plate with enough strength to resist the bending effect can be obtained by combining FE and Taguchi analyses. The optimal designed ATTM plate with patient-matched facial contour fabricated using AM provides superior stabilization for ZMC comminuted fractured bone segments.

Methodology for sample preparation and size measurement of commercial ZnO nanoparticles.

This study discusses the strategies on sample preparation to acquire images with sufficient quality for size characterization by scanning electron microscope (SEM) using two commercial ZnO nanoparticles of different surface properties as a demonstration. The central idea is that micrometer sized aggregates of ZnO in powdered forms need to firstly be broken down to nanosized particles through an appropriate process to generate nanoparticle dispersion before being deposited on a flat surface for SEM observation. Analytical tools such as contact angle, dynamic light scattering and zeta potential have been utilized to optimize the procedure for sample preparation and to check the quality of the results. Meanwhile, measurements of zeta potential values on flat surfaces also provide critical information and save lots of time and efforts in selection of suitable substrate for particles of different properties to be attracted and kept on the surface without further aggregation. This simple, low-cost methodology can be generally applied on size characterization of commercial ZnO nanoparticles with limited information from vendors.

Biomechanical evaluation of a novel pedicle screw-based interspinous spacer: A finite element analysis.

Interspinous spacers have been designed to provide a minimally invasive surgical technique for patients with lumbar spinal stenosis or foraminal stenosis. A novel pedicle screw-based interspinous spacer has been developed in this study, and the aim of this finite element experiment was to investigate the biomechanical differences between the pedicle screw-based interspinous spacer (M-rod system) and the typical interspinous spacer (Coflex-F™). A validated finite element model of an intact lumbar spine was used to analyze the insertions of the Coflex-F™, titanium alloy M-rod (M-Ti), and polyetheretherketone M-rod (M-PEEK), independently. The range of motion (ROM) between each vertebrae, stiffness of the implanted level, the peak stress at the intervertebral discs, and the contact forces on spinous process were analyzed. Of all three devices, the Coflex-F™ provided the largest restrictions in extension, flexion and lateral bending. For intervertebral disc, the peak stress at the implanted segment decreased by 81% in the Coflex-F™, 60.2% in the M-Ti and 46.7% in the M-PEEK when compared to the intact model. For the adjacent segments, while the Coflex-F™ caused considerable increases in the ROM and disc stress, the M-PEEK only had small changes.

Analysis of titanium dioxide and zinc oxide nanoparticles in cosmetics.

There have been rapid increases in consumer products containing nanomaterials, raising concerns over the impact of nanoparticles (NPs) to humankind and the environment, but little information has been published about mineral filters in commercial sunscreens. It is urgent to develop methods to characterize the nanomaterials in products. Titanium dioxide (TiO2) and zinc oxide (ZnO) NPs in unmodified commercial sunscreens were characterized by laser scanning confocal microscopy, atomic force microscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). The results showed that laser scanning confocal microscopy evaluated primary particle aggregates and dispersions but could not size NPs because of the diffraction limited resolution of optical microscopy (200 nm). Atomic force microscopy measurements required a pretreatment of the sunscreens or further calibration in phase analysis, but could not provide their elemental composition of commercial sunscreens. While XRD gave particle size and crystal information without a pretreatment of sunscreen, TEM analysis required dilution and dispersion of the commercial sunscreens before imaging. When coupled with energy-dispersive X-ray spectroscopy, TEM afforded particle size information and compositional analysis. XRD characterization of six commercial sunscreens labeled as nanoparticles revealed that three samples contained TiO2 NPs, among which two listed ZnO and TiO2, and displayed average particle sizes of 15 nm, 21 nm, and 78 nm. However, no nanosized ZnO particles were found in any of the samples by XRD. In general, TEM can resolve nanomaterials that exhibit one or more dimensions between 1 nm and 100 nm, allowing the identification of ZnO and TiO2 NPs in all six sunscreens and ZnO/TiO2 mixtures in two of the samples. Overall, the combination of XRD and TEM was suitable for analyzing ZnO and TiO2 NPs in commercial sunscreens.

A review of quality surveillance projects on cosmetics in Taiwan.

The Food and Drug Administration in Taiwan is responsible for the quality regulation and control of cosmetics. In order to have a clear understanding of the trends in the product quality monitoring outcomes and the regulatory control measures over the past years, this study has put together the reports of nine cosmetic surveillance projects conducted between 1982 and 2012. The findings can be used as a reference in developing a more solid quality monitoring plan and management system for cosmetic products. Results show that permanent wave products, hair dye products, and phthalate esters in cosmetic products have the highest average noncompliance rates at 39.2%, 14.2%, and 11.2%, respectively. These are followed by the average noncompliance rates of mercury in products, sunscreen products, and microorganisms in products, at 8.5%, 7.1%, and 5.5%, respectively, and the remaining three projects averaging below 4.1%. Since 1997, when new standards were announced and assistance to manufacturers was reinforced, the noncompliance rates of permanent wave products decreased annually, until 2007, when it was fully qualified for the standards. Overall, the study showed that the noncompliance rates of permanent wave products and for levels of phthalate esters, mercury, and hydroquinone in cosmetic products have all decreased in the previous years. The results of surveillance projects conducted after 2005 revealed only one noncompliance sample with lead, arsenic, and cadmium, whereas the surveillance projects on permanent wave products and chloroform- and 1,4-dioxane-containing products revealed full compliance with regulation standards. However, the noncompliance rates for microorganisms in cosmetics and the ingredients in hair dye products and sunscreen products were still high. These high-risk products must be monitored. These surveillance projects are conducted to ensure the safety of cosmetics in the market.