Role Of Stearic Acid Research Articles

Role of Stearic Acid toward the Gelation of Cocoa Butter and Wheat Germ Oil-Based Oleogels: Preparation, Physical Properties, and Application in Topical Mupirocin Delivery

Role of Stearic Acid toward the Gelation of Cocoa Butter and Wheat Germ Oil-Based Oleogels: Preparation, Physical Properties, and Application in Topical Mupirocin Delivery

Role of Stearic Acid as the Crystal Habit Modifier in Candelilla Wax-Groundnut Oil Oleogels

This study investigated the effects of incorporating stearic acid (SAC) in candelilla wax (CW) and groundnut oil (GO) oleogel with potential health benefits as an alternative to saturated fats in processed foods. Results showed that SAC possesses crystal habit-modifying properties on the oleogels, causing its average crystallite size to increase, as observed through polarized light microscopy and XRD analysis. Additionally, SAC caused an increase in ordering within the crystallite network as a result of the decrease in d-spacing. Interestingly, the firmness of the oleogels remained unaffected, even at a higher fraction of SAC. It is believed to be due to the interference caused by the crystallization of high-melting SAC within the fine crystal network of CW-GO oleogel. However, adding 3 mg of SAC significantly increased the work of the shear of the oleogel (SAC3), which decreased the spreadability. As observed through colorimetric analysis, SAC3 showed a dense and uniform distribution of prominent bright crystals with minimal amorphous regions, leading to a high whiteness index. SAC3 also demonstrated the highest compactness and dislocation density among the oleogels, likely due to the formation of prominent crystals. However, SAC did not affect the overall oleogel crystallization rate. SAC3 had delayed secondary crystallization and thermal equilibrium by having a prolonged crystallization time of CW crystals. In the case of controlled delivery studies, the addition of SAC improved CPCR. On the other hand, CPCR decreased with the increase in SAC amount, where SAC3 showed a moderate curcumin release ability among the oleogels.

Stearic acid induces CCK and GLP-1 upregulation via GPR120/PLC-β, leading to reduced appetite in Hu sheep fed with rice straw.

Due to the poor palatability of straw, feeding untreated rice straw reduces ruminant feed intake, thus affecting the production efficiency of animal husbandry. However, the detailed mechanism by which straw affects ruminants' feed intake is unclear. Therefore, this study aimed to elucidate the molecular mechanism by which a rice straw (RS)-based diet affects appetite regulation in Hu sheep. We found that RS promoted the secretion of cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) and decreased feed intake. Blood metabolomics showed that RS activated the arachidonic acid metabolism, biosynthesis of unsaturated fatty acids, linoleic acid metabolism, and alpha-linolenic acid metabolism pathways, and the secretion of stearic acid (SA), their metabolic end product, increased significantly. GPR120, one of the classical receptors of long-chain fatty acids (LCFAs), can be involved in appetite regulation. However, the role of SA in satiety hormone regulation mediated by GPR120 in ruminants is unclear. In this study, in vivo experiments showed that in sheep fed with RS, SA increased significantly and activated GPR120/Ca2+, increasing the secretion of the satiety hormones CCK and GLP-1. In vitro mechanism studies showed that SA promotes GLP-1 and CCK secretion by activating GPR120-mediated downstream PKC and IP3R signaling pathways of PLCβ.

Solid lipid particle-based tablets for buccal delivery: The role of solid lipid particles in drug release

This study aims to develop mucoadhesive tablets containing solid lipid particles for controlled release pattern through buccal delivery. The buccal tablets containing drug-loaded solid lipid particles (SLPs) were fabricated using the ultrasonication method and lyophilisation with the incorporation of bioadhesive excipients. The role of stearic acid in the lipid phase and the effects of different surfactant contents were thoroughly evaluated. The stearic acid in formulations showed its impacts on particle formation and release characteristics. Although liquid surfactants could create SLPs of nano-size, the dissolution profile resulted in low drug release. The combination of a solid surfactant and a liquid surfactant resulted in better tablet formation and an improvement in the dissolution rate of prednisolone in both immediate release and sustained release. Furthermore, an adaptable pH surface, long mucoadhesion time, and satisfactory permeation resulted in suitable conditions for buccal tablet design without causing any irritations. The success of this work could contribute to a new strategy for improving the bioavailability of poorly water-soluble drugs by buccal delivery.

On the Role of Stearic Acid on the Surface Properties of Carbon Nanotubes

In this article, modification of multiwalled carbon nanotubes (MWCNTs) with stearic acid (SA) was done using the wet chemical method. For this aim, MWCNTs were treated with high-concentrated nitric acid to create a functional group as a linkage between MWCNTs and SA. The modified MWCNTs with SA were examined by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), differential scanning calorimeter (DSC), and thermogravimetery analysis (TGA) instruments. The results of TGA and DSC indicate the deposition of about 4.3 wt% of SA on the surface of MWCNTs. This proves that the deposition of stearate with a medium diameter size of 20 nm on the surface of MWCNTs can be divided into physical and chemical adsorption. As well, the esterification occurs on the surface of functionalized MWCNTs and there is no SA unreacted on the surface of MWCNTs.

The role of stearic acid in ascorbic acid protection from degradation: a heterogeneous system for homogeneous thermodynamic data

A heterogeneous system between vitamin C and stearic acid was characterized by thermal and crystallographic analyses. The results showed that such a system prevents vitamin C from thermal decomposition. The evidence was provided by implementing a new protocol associating chromatic assays and thermal analyses in order to quantify the percentage of non-degraded vitamin C. The results collected with the vitamin C–stearic acid mixtures allowed deducing coherent interpretation of the results obtained with pure vitamin C at different heating scan rates. Vitamin C mainly degrades upon melting but also in the solid state for temperature close to the melting point when the heating rates are very low. Under these conditions, the temperature determined at the onset of the DSC graphs cannot be associated with the melting temperature but with a fusion-degradation phenomenon. At higher scan rates, the onset as well as the endothermic value of the signal increase to reach plateau values. These values have been identified as the temperature and enthalpy values of melting of vitamin C according to the results obtained from the heterogeneous system.

Study on the Role of Stearic Acid and Ethylene-bis-stearamide on the Mechanical Alloying of a Biomedical Titanium Based Alloy

The present study examines the influence of different contents and types of process control agent (PCA), i.e., stearic acid (SA) and ethylene-bis-stearamide (EBS), on the microstructural evolution and characteristics of Ti-16Sn-4Nb (wt pct) alloy powders and bulk samples. The characterization of the powders and bulk samples was carried out by using chemical analysis, optical microscopy, scanning electron microscopy (SEM) combined with energy-dispersive spectrometry (EDS), and X-ray diffractometry. Results indicated that the powder recovered from the ball milling containers increased with increasing amounts of SA and EBS. Furthermore, adding more SA or EBS to the powder mixture resulted in a considerably smaller particle size, with a flaky-shaped morphology for the given ball milling time. Also, a slightly higher effectiveness was found for EBS when compared to SA. Meanwhile, the addition of both SA and EBS led to a delay in the alloy formation during mechanical alloying (MA) and caused contamination of the material with mainly carbon (C) and oxygen (O). An optimum amount of 1 wt pct PCA led to a good balance between cold welding and fracturing, and thus favored the formation of the titanium alloy. The microstructural observation of the bulk alloy showed a homogeneous distribution of fine Nb-rich β-phase colonies within the α-Ti matrix with the addition of PCA less than 1 wt pct.

Hydroxypropyl methylcellulose (HPMC) formulated films: Relevance to adhesion and friction surface properties

Cellulose derivatives constitute one of the most dedicated polymers used in the production of film coatings (tablets, capsules …). The effect of the composition of hydroxypropyl methylcellulose (HPMC)-stearic acid films on the surface physico-chemical properties was investigated. Incorporation of stearic acid into HPMC films induces strong changes on surface structure, hydrophobic/hydrophilic character, adhesion and friction characteristics. The variations observed suggest an accumulation of stearic acid on film surfaces, resulting a decrease of its roughness and surface free energy. The nano-adhesion and nano-friction experiments were evaluated by using AFM/FFM, while the macro-adhesion and macro tribological studies were performed on tack test and pin-on-disk tribometer respectively. In all the cases, it was found that the hydrophobic character of stearic acid leads to decrease adhesion and friction at the two scales. The surface capillary force plays a key role in these properties. In addition, the study indicates the interplay of adhesion in friction property of HPMC films and the role of stearic acid as lubricant.

On role of stearic acid on morphology of Al–SiCp composite powders produced by mechanical alloying method

In the present study high energy ball mill has been conducted to produce Al matrix composite reinforced with silicon carbide (SiC) at different milling time. To evaluate the role of stearic acid content on powder morphology of Al–SiC composite, the material has been fabricated with different stearic acid content, namely 0·1, 0·5, 1 wt-%. The SEM micrographs taken from Al–SiC composite powder show that the size of composite powders depends strictly on both stearic acid content and milling time. At constant milling time the smaller particles have been observed as well as SiC content increases with increasing stearic acid content. The uniformity of composite powders was so much better as stearic acid content increases.

Role of stearic acid in the strain-induced crystallization of crosslinked natural rubber and synthetic cis-1,4-polyisoprene

Strain-induced crystallization of crosslinked natural rubber (NR) and its synthetic analogue, cis-1,4-polyisoprene (IR), both mixed with various amounts of stearic acid (SA), were investigated by time-resolved X-ray diffraction using a powerful synchrotron radiation source and simultaneous mechanical (tensile) measurement. No acceleration or retardation was observed on NR in spite of the increase of SA amount. Even the SA-free IR crystallized upon stretching, and the overall crystallization behavior of IR shifted to the larger strain ratio with increasing SA content. No difference due to the SA was detected in the deformation of crystal lattice by stress for both NR and IR. These results suggested that the extended network chains are effective for the initiation of crystallization upon stretching, while the role of SA is trivial. These behaviors are much different from their crystallization at low temperature by standing, where SA acts as a nucleating agent.

Role of Stearic Acid in Preparing EPDM/Clay Nanocomposites by Melt Compounding

EPDM/organic clay (OC) nanocomposites were prepared by melt blending. XRD results showed that if OC mixed with EPDM matrix, macromolecule chains are difficult to intercalate into the layers while stearic acid (SA) could easily intercalate into the OC interlayers under pretreating conditions (S-OC) and expand the interlayer spacing 2.6 nm of OC to a wider distance of 3.9 nm; EPDM could not further expand the distance of S-OC during the followed mixing process and the structure SA intercalating into OC is kept. TEM observation showed S-OC improved the dispersion of OC in EPDM, and FT-IR results indicated the esterification reaction occurred between carboxyl groups of SA and hydroxyl groups of OC, which was believed to be the driving force of SA intercalation. The tensile strengths of the nanocomposites are improved with increasing amount of SA, and the stresses at low strain are almost the same, due to the physical interaction between OC and EPDM macromolecules.

Antagonism between phenolic antioxidants and an organic acid

The role of stearic acid in the kinetics of polypropylene oxidation in the presence of 2,2 1-methylene-bis(4-methyl-6- tert-butyl-phenol) and 3,5-di- tert-butyl-4-hydroxyphenylpropionic acid diethyleneglycol ester has been studied. It has been demonstrated that this acid increases the critical concentration of the antioxidant with little effect on the rate constant of its consumption. The role of esterification reactions between antioxidant and acid is negligible. It is presumed that oxidant effectiveness is reduced by formation of complexes of antioxidant and acid.