Glyceryl ether (mono-tert-butoxypropanediol) in emulsion system

This paper reports the effects of glyceryl ether specifically mono-tert-butoxypropanediol on oil in water emulsion system. Based on 12 HLB value, screening for stable emulsions was carried out without the presence of glyceryl ether. A stable emulsion was used as a control. Then the effects of glyceryl ether on the emulsion system were investigated. The emulsions prepared were analyzed for stability, viscosity, pH value, particle size, in vitro dermal irritation potential, in vitro ocular irritation potential and also moisturizing property. The incorporation of glycerol in the emulsion system was also done for comparison. Emulsions with glyceryl ether showed lower viscosity values than emulsions with glycerol. Furthermore, the emulsions also exhibited moisturizing property compared to the control emulsion. Glyceryl ether is suitable to be used in cosmetic products which require reduced viscosity but retain its skin hydration property

Skin and eye irritation assessment of oil palm (Elaeis guineensis) leaf extract for topical application

Many types of phytochemicals have been found to be present in oil palm leaf and could potentially be used as functional ingredients for skincare product. However, as of today, there is no published report on hazard identification and safety assessment of oil palm ( Elaeis guineensis) leaf extract (OPLE), particularly on skin and eye irritation. In this study, potential hazard of OPLE on skin and eye irritation was evaluated as an initial step to the safety assessment of OPLE. In vitro cell viability study of OPLE on normal human dermal fibroblasts showed that OPLE was nontoxic to the cells with percentage viability more than 90% after 24 and 48 hours of incubation. Skin irritation potential of OPLE was evaluated using in vitro SkinEthic reconstructed human epidermis (RHE) model (Organization for Economic Cooperation and Development [OECD] Test Guideline 439, 2015), while eye irritation potential was evaluated using in vitro SkinEthic Human corneal epithelium (HCE) model (OECD test guideline 492, 2017). Hazard identification results showed that OPLE at 1%, 5%, and 10% (wt/wt) was classified as nonirritant to the skin and eye where mean tissue viabilities of SkinEthic RHE and SkinEthic HCE were more than 50% and 60%, respectively. Therefore, we recommend a further safety assessment, such as human patch testing, to confirm the nonirritant of OPLE

Design and optimization of tocotrienol rich fraction nanoemulsion system for cosmeceutical application

Highly stabilized nanoemulsion system requires high concentration of surfactant, high homogenization pressures and process cycles. However, the high surfactant concentrations may induce skin irritation while the high homogenization pressures and process cycles may incur higher operation cost. Another important problem is the absorption inefficiency of active such as tocotrienol rich fraction (TRF) into skin which affects product efficacy. This study aims to improve the stability of TRF nanoemulsion and effective absorption of TRF into skin by designing TRF nanoemulsion using Hansen Solubility Parameter (HSP) concept. The HSP concept allows alteration of the oil phase solubility which reduces Ostwald ripening and improves solubility of TRF into skin. TRF nanoemulsion was prepared by optimizing high shear homogenization conditions with pressure of 15,000 psi and minimum of 3 process cycles which yielded nanoemulsions of average droplet size of 137 ± 3 nm with zeta potential of -24.9 ± 2.2 mV and polydispersity index of 0.22. Nanoemulsions with less than 3% surfactant resulted in less significant droplet size reduction compared to nanoemulsion with more than 5% surfactant. From Stokes Equation, the velocity of TRF nanoemulsions with droplet size between 50 and 53 nm was calculated in the region of 10-15 m.s-1. Oswald Ripening, which is the main destabilization factor affecting nanoemulsion stability, was effectively reduced by increasing volume fraction of TRF to φ = 0.4 – 0.5 of the nanoemulsion disperse phase. The solubility gap based on HSP was higher at 2.46 - 3.12 indicating that the modified oil phase has lower solubility which inhibited Ostwald ripening. At these volume fractions, the system is approaching thermodynamic stability where Ostwald Ripening rate has plateau. Optimization of nanoemulsion with TRF in combination with glycerine and octocrylene was predicted and proven to have better delivery of TRF into skin compared to other combinations of TRF. The solubility gap based on HSP was lower at 4.2 indicating the oil phase has higher solubility into skin. The penetration profiles via tape stripping technique showed that optimized TRF nanoemulsion recorded highest TRF at 0.493 μg.cm-2. The steady-state flux proved that TRF nanoemulsion optimized with HSP concept delivered the highest average flux value (0.2556 μg/cm2.h), followed by the TRF nanoemulsion (0.1998 μg/cm2.h) and TRF Macroemulsion (0.1360 μg/cm2.h). This indicated that optimized TRF Nanoemulsion allows more TRF to permeate through the skin via passive diffusion. In vitro ocular and dermal irritection based on protein assays and in vitro ocular and dermal irritation using reconstructed human epidermis and human epithelial models showed that TRF nanoemulsions did not induce any ocular or dermal irritations. In vitro sun protection factor test and in vivo skin hydration showed that TRF nanoemulsion was having better UV protection and effective in maintaining higher level of skin hydration. This study has shown that stable TRF nanoemulsion with higher absorption of TRF into skin can be achieved by designing TRF nanoemulsion based on HSP concept

Glyceryl Ether (mono-tert-butoxypropanediol) in Emulsion System

This paper reports the effects of glyceryl ether specifically mono-tert-butoxypropanediol on oil in water emulsion system. Based on 12 HLB value, screening for stable emulsions was carried out without the presence of glyceryl ether. A stable emulsion was used as a control. Then the effects of glyceryl ether on the emulsion system were investigated. The emulsions prepared were analyzed for stability, viscosity, pH value, particle size, in vitro dermal irritation potential, in vitro ocular irritation potential and also moisturizing property. The incorporation of glycerol in the emulsion system was also done for comparison. Emulsions with glyceryl ether showed lower viscosity values than emulsions with glycerol. Furthermore, the emulsions also exhibited moisturizing property compared to the control emulsion. Glyceryl ether is suitable to be used in cosmetic products which require reduced viscosity but retain its skin hydration property

Preparation and evaluation of photoprotective kenaf seed oil nanocarriers-based cream of tocotrienol-rich fraction

Applications of nanotechnology and vegetable oil in topical formulation have emerged to provide benefits to develop effective and safe advanced biocosmetic prototypes. The study aimed to optimize the ratio of UV filters in kenaf (Hibiscus cannabinus L.) seed oil nanocarrier to form a sunscreen formulation. The nanocarriers were characterized based on particle size, polydispersity index, encapsulation efficiency, UV absorption, Raman microscopy, and high-resolution transmission electron microscopy analysis. The selected nanocarrier was added to a tocotrienol-rich fraction (TRF) cream and subjected to photoprotection and functional analysis to determine its skin beneficial properties based on cellular antioxidant capacity and relative protein expression on fibroblasts. The results revealed that nanocarriers with particle sizes ranging from 180 nm to 240 nm showed > 90% of encapsulation efficiency for UV filters. Sample F5 contained 1.25% of diethylamino hydroxybenzoyl hexyl benzoate (DHHB) and 0.75% of ethylhexyl triazone (EHT), having a spherical shape at particle size 204.80 nm with > 95% of UV filter encapsulation and high intensity in both UVA and UVB spectra. The cream produced from F5 and TRF (NLC-TRF cream) indicated no cytotoxicity and was able to provide sun protection factor (SPF) value of 53 and cellular antioxidant capacity of 45.13%. Besides, a significant protein upregulation (1.29-fold for fibroblast growth factor, 7.77-fold for vascular endothelial growth factor, 11.21-fold for transforming growth factor-β1, and 1.69-fold for tissue inhibitor matrix metalloproteinase-1) and downregulation for matrix metalloproteinase-1 and − 2 resulted after 24 hr of treatment. The application of nanocarriers in TRF cream can enhance the photoprotection, skin-protective properties in cellular antioxidant capacity, and protein expression which could be a promising delivery system in sunscreen formulations

In vitro safety evaluation of sunscreen formulation from nanostructured lipid carriers using human cells and skin model

There is a risk of toxicological reactions due to systemic absorption and photo-instability of sunscreens. The study aimed to investigate the safety profile (cytotoxicity, phototoxicity, photostability, UV filter release profile, and skin irritation properties) of sunscreen (NLC-TRF sunscreen) produced from nanostructured lipid carriers (NLCs) and tocotrienol-rich fraction (TRF). The cytotoxicity and phototoxicity of the sunscreen were evaluated on normal human dermal fibroblast (NHDF) and skin irritation properties was tested on skin model. Besides, the photoprotection in pre- and post-UV irradiation were analysed to determine the photostability. Additionally, the release profile for UV filters (diethylamino hydroxybenzoyl hexyl benzoate (DHHB) and ethylhexyl triazone (EHT)) were evaluated. The NLC-TRF sunscreen demonstrated no cytotoxicity and skin irritation to cause cell death. It showed no phototoxic effect and high photostability up to 10 Minimal Erythema Dose (MED) to ensure high SPF value above 50 and broad-spectrum of UV absorption. The NLC-TRF sunscreen implies its safety for topical application with sustainable release profile for UV filter (cumulative release of 28% for DHHB and 40% for EHT after 8 h) due to the application of NLCs. The results suggest that the NLC-TRF sunscreen is an advanced formulation with improved stability and is safe for topical delivery

Application of kenaf seed oil-nanostructured lipid carrier to palm-based α-tocopherol cream for photoprotection

The application of a nanostructured lipid carrier (NLC) to ultraviolet (UV) filter encapsulation was found to enhance its safe use. In this work, a kenaf seed oil-NLC (KSO-NLC) coloaded with 1% diethylamino hydroxybenzoyl hexyl benzoate and 1% ethylhexyl triazone was used as an active ingredient in α-tocopherol cream to develop a photoprotective prototype. It was then subjected to further analysis to determine its physical properties, storage stability, and cytotoxicity. The ratio of KSO-NLC to α-tocopherol cream was optimized based on the sun protection factor (SPF) value using a UV transmittance analyzer. The physical properties of the samples were analyzed, and the amount of α-tocopherol was quantified by ultra-high-performance liquid chromatography. The optimized sample was then evaluated for in vitro antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid assays. Meanwhile, in vitro cytotoxicity was studied on a normal human dermal fibroblast cell line using thiazolyl blue tetrazolium bromide and cell counting kit-8 assays. The sample of KSO-NLC to α-tocopherol cream in a ratio of 1:2 (N3) showed SPF value >50. Besides, the samples showed microbial stability and sustainable α-tocopherol content upon 12 weeks of storage. The cytotoxicity evaluation of N3 and α-tocopherol cream (N5) showed >100% cell proliferation, which indicated that there is no side effect on the cell growth, while triggering the cell proliferation with the presence of bioactive compounds. Overall, the findings of the study are promising for the development of new sunscreen formulation with the utilization of KSO-NLC and palm-based α-tocopherol cream