Zahariah Ismail

Phase Behavior and Formulation of Palm Oil Esters o/w Nanoemulsions Stabilized by Hydrocolloid Gums for Cosmeceuticals Application

Palm oil esters (POEs) are wax esters derived from palm oil and cis-9-octadecen-1-ol. The excellent wetting behaviour of the esters without the oily feel make them have great potentials in the manufacture of cosmeceutical and pharmaceutical products. However, little is known about their phase behaviors in ternary systems. The purpose of this investigation was to construct phase diagram of the POEs and mixed surfactants and to consequently select nanoemulsions composition for further studies. The preparation and characterization of oil-in-water nanoemulsions stabilized by hydrocolloid gums were then studied. Two types of nonionic surfactants were selected, namely Tween 80 (T80) and Span 80 (S80). Ternary phase diagram of POEs:Tocotrienol/T80:S80 (80:20)/water system was constructed at 25.0 ± 0.5°C. The emulsification properties of 2 hydrocolloids gum (xanthan gum, carbopol ultrez 20 copolymer) were investigated. Gum dispersions were prepared in water (0.8%) and emulsified with 30% oil using a Polytron homogenizer. The flow curve of the emulsions always exhibited shear thinning behavior and obeys the power law viscosity. The emulsions with carbopol ultrez 20 copolymer was the most stable emulsions which composed of very small oil droplets (50% < 142.43 nm) with a narrow size distribution.

Characterization and effect on skin hydration of engkabang-based emulsions.

Formulations containing engkabang fat and engkabang fat esters, F10 and E15 respectively were prepared using a high-shear homogenizer, followed by a high-pressure homogenizer. Both formulations were stable at room temperature, at 45 °C, and after undergoing freeze-thaw cycles. The particle sizes of F10 and E15 after high pressure were 115.75 nm and 148.41 nm respectively. The zeta potentials of F10 and E15 were −36.4 mV and −48.8 mV respectively, while, the pH values of F10 and E15 were 5.59 and 5.81 respectively. The rheology of F10 and E15 showed thixotropy and pseudoplastic behavior respectively. There were no bacteria or fungal growths in the samples. The short-term moisturizing effect on 20 subjects analyzed by analysis of variance (ANOVA), gave p-values of 7.35×10−12 and 2.77×10−15 for F10 and E15 respectively. The hydration of the skins increased after application of F10 and E15 with p-value below 0.05.

Ternary Phase Behaviour of Dihydroxystearic Acid/Octyl Dihydroxystearate/Medium Chain Triglycerides

Abstract Dihydroxystearic acid (DHSA) and octyl dihydroxystearate (DHSA ester) have been successfully prepared from palm oleic acid. Preliminary results showed that these compounds are suitable in personal care and cosmetics products. The objective is to study the phase behaviour in the ternary system of DHSA/DHSA ester/MCT (medium chain triglycerides) at 85°C. Phase changes were observed through polarizing light, whereas the formation of texture was confirmed using a polarizing microscope in combination with heating. From the ternary phase diagram, results show that all ratios of DHSA/DHSA ester were completely in two‐phase region with various concentrations of MCT. Needles and spherulite textures were found in this system.

Phase behavior of engkabang fat with nonionic surfactants

Abstract Phase behavior of engkabang fat was determined through the construction of ternary phase diagrams using nonionic surfactants. Several phase regions appeared in the ternary phase diagrams such as isotropic, homogenous, liquid crystal, two phase and three phase regions. The increase of hydrophilic-lipophilic balance (HLB) values of the nonionic surfactants used gave larger isotropic and homogenous region in the ternary phase diagrams. The combination of engkabang fat:Solubilisant Gamma (2:1) in the ternary phases diagram gave an even larger isotropic and homogenous regions as well as the formation of liquid crystal region.

Ultra Moisturizing Skin Whitening Lotion Enriched with Tocotrienols

A two-in-one product, a skin whitening lotion enriched with tocotrienols that ultra moisturizes and lightens, was successfully prepared. The basic formulation for this product was prepared by constructing a ternary phase diagram consisting of medium chain triglycerides (MCT), mixed glucose-based emulsifiers, and deionized water at 80°C. The right ratio of these compounds was selected based on liquid crystalline region to produce a stable product. Other palm-based materials were added to the basic formulation. The product was found to be stable for more than 3 months upon storage stability test. The mean droplet size is 10 µm with a monomodal distribution pattern which prevents agglomeration. This decreases Brownian motion, thus prolonging its stability. Long-term acute moisturizing tests showed a significant increase of between 21.2% and 15.4% hydration for 5 and 6 weeks, respectively. The efficacy testing on 20 subjects confirmed a reduction in melanin content, lightening the skin in 4 weeks.

Lyotropic Mesophases of Nonionic Sugar‐Based Emulsifiers

Abstract A preliminary study of the phase behavior of a ternary system of water and emulsifier mixtures has been carried out at 80°C under the polarizing light microscope. The emulsifiers used were Glucate SS (methyl glucose sesquistearate) and Glucamate SSE‐20 (PEG‐20 methyl glucose sesquistearate).The textures of the mesophases of these systems were confirmed by polarized microscopy. Lamellar phases (Lα) were observed at Glucate SS and Glucamate SSE‐20 weight ratios of 40/60, 30/70 and 20/80. Also present in the phase diagram are a three phase region, a two phase region comprising hexagonal (H1) and isotropic (L1) phases, Lα + L1 and the isotropic single phase.

Phase Behavior and Rheology of Mixed Nonionic Sugar-Based Surfactants

ABSTRACT The rheological properties of 40/60, 30/70, and 20/80 by weight ratio of methyl glucose sesquistearate (glucate SS) and PEG-20 methyl glucose sesquistearate (glucamate SSE-20) at 1-phase (Lα) and 2-phase (L1 + Lα) region were studied. These regions are fully developed lamellar liquid crystal (Lα) ranging from 29–31% water, lamella liquid crystal, and isotropic matrix which is closed Lα region (L1 + Lα) ranging from 16–19% water, and lamella liquid crystal in which birefringence is not prominent and isotropic matrix (L1 + Lα)′ ranging from 34–44% water. The viscosity, yield value and thixotropy behavior were studied at 80°C using a Brookfield viscometer. A pseudoplastic behavior exhibits at all the phases for mixed surfactants. The viscosity of mixed surfactants indicated as fall in the following order Lα > (L1 + Lα)′ > (L1 + Lα). The yield values of 40/60 and 20/80 exhibit the same ranking as the viscosity but not for 30/70. The highest plastic viscosity was observed in Lα region. The consistency index or viscosity index increased at Lα and it decreased in the flow index (flow index to describe the flow-curve, i.e., Newtonian, dilatant, pseudoplastic or plastic). The thixotropy behavior in that required a longer time to recover its structure of mixed surfactants showed at the Lα. Oily streaks pattern exhibits the biggest hysteresis loop.

Physicochemical Properties of a Ternary System Based on Medium Chain Triglycerides/Water/Mixed Nonionic Sugar-Based Surfactants

Equal ratios of medium chainlength triglycerides and water were emulsified with 5% w/w of mixed nonionic surfactants with various hydrophilic-lipophilic balance (HLB) values. The HLB numbers ranged from 15 to 6.6. Emulsifiers with HLB numbers 15, 14.2, 13.3, and 12.5 produced low viscosity milk-like liquid, 11.6, 10.8, 10, and 9.1 produced cream, 8.3 and 7.4 produced paste like consistency, and 6.6 produced a coarse emulsion. The effects of HLB on stability, particle size, and rheological properties were studied. Emulsifiers with intermediate HLB numbers produced emulsions that are stable for 30 days at room temperature but a thin layer of oil on top of the emulsion was observed at 45°C. The thin oil layer can be redispersed with mild agitation without loss of stability. Emulsifiers with high and low HLB number (15, 14.2, 13.3, 6.6) produced emulsions that were unstable at both storage conditions. The stability of the emulsions correlate well with the particle size. The curve flow plot for most of the emulsions fit the Herschel Bulkley model. They exhibit a pseudoplastic type behavior. Emulsifiers with different HLB numbers also affect the shear stress at zero shear, τ0, and the yield value, τ.

Ultra Moisturizing Anti-Wrinkle Lotion Enriched with Tocotrienols

A stable palm-based anti-wrinkle lotion enriched with tocotrienols was successfully prepared. The stability of the product was due to the presence of liquid crystalline structure in the emulsion system. It helps in bringing the active to the dermis layer. Functionality active ingredients such as tocotrienols and anti-wrinkle were added in the formulation. A commercial plant extract was used to strengthen the collagen seated at the dermis layer. The product was formulated to pH 5.5 which is suitable for the skin. The mean droplet size is 10.2 µm with a monomodal distribution pattern which prevents agglomeration. This will decrease Brownian motion, thus prolonging its stability. Long-term acute moisturizing tests show a significant increase of between 24% and 17% hydration for five and six weeks respectively. The efficacy testing on 12 subjects confirmed a reduction in natural fine wrinkles on faces during aging or premature aging at −7.6%.

Selection of Polymorphic Structure in Dihydroxystearic Acid/Octyl dihydroxystearate/RBD Palm Kernel Olein & Medium Chain Triglycerides in Cosmetic and Personal Care Formulation

Dihydroxystearic acid (DHSA) and octyl dihydroxystearate (DHSA‐octyl ester) have been successfully prepared from palm oleic acid. Preliminary results showed that these compounds are suitable in personal care and cosmetics products. The objective is to study the phase behaviors in ternary system of DHSA/DHSA‐octyl ester/RBD palm kernel olein (RBDPKOo) and medium chain triglycerides (MCT) at 85°C. The phase changes were observed through polarizing light while the formation of texture was confirmed using polarizing microscope combination with heating. From the ternary phase diagram, results showed that all ratios of DHSA/DHSA‐octyl ester were completely in two‐phase region with various concentrations of RBDPKOo/MCT. Needles and spherulite textures were found in this system. The viscosity and thixotropy of these mixtures were also determined using rheometer. DHSA and DHSA‐octyl ester has a melting point of 84.4°C and 64.3°C, respectively.