Noraini Ahmad

Influence of nonionic branched-chain alkyl glycosides on a model nano-emulsion for drug delivery systems

The effect of incorporating new nonionic glycolipid surfactants on the properties of a model water/nonionic surfactant/oil nano-emulsion system was investigated using branched-chain alkyl glycosides: 2-hexyldecyl-β(/α)-D-glucoside (2-HDG) and 2-hexyldecyl-β(/α)-D-maltoside (2-HDM), whose structures are closely related to glycero-glycolipids. Both 2-HDG and 2-HDM have an identical hydrophobic chain (C16), but the former consists a monosaccharide glucose head group, in contrast to the latter which has a disaccharide maltose unit. Consequently, their hydrophilic-lipophilic balance (HLB) is different. The results obtained have shown that these branched-chain alkyl glycosides affect differently the stability of the nano-emulsions. Compared to the model nano-emulsion, the presence of 2-HDG reduces the oil droplet size, whereas 2-HDM modify the properties of the model nano-emulsion system in terms of its droplet size and storage time stability at high temperature. These nano-emulsions have been proven capable of encapsulating ketoprofen, showing a fast release of almost 100% in 24h. Thus, both synthetically prepared branched-chain alkyl glycosides with mono- and disaccharide sugar head groups are suitable as nano-emulsion stabilizing agents and as drug delivery systems in the future.

Physicochemical Characterization of Natural-like Branched-Chain Glycosides toward Formation of Hexosomes and Vesicles

Synthetic branched-chain glycolipids have become of great interest in biomimicking research, since they provide a suitable alternative for natural glycolipids, which are difficult to extract from natural resources. Therefore, branched-chain glycolipids obtained by direct syntheses are of utmost interest. In this work, two new branched-chain glycolipids are presented, namely, 2-hexyldecyl β(α)-D-glucoside (2-HDG) and 2-hexyldecyl β(α)-D-maltoside (2-HDM) based on glucose and maltose, respectively. The self-assembly properties of these glycolipids have been studied, observing the phase behavior under thermotropic and lyotropic conditions. Due to their amphiphilic characteristics, 2-HDG and 2-HDM possess rich phase behavior in dry form and in aqueous dispersions. In the thermotropic study, 2-HDG formed a columnar hexagonal liquid crystalline phase, whereas in a binary aqueous system, 2-HDG formed an inverted hexagonal liquid crystalline phase in equilibrium with excess aqueous solution. Furthermore, aqueous dispersions of the hexagonal liquid crystal could be obtained, dispersions known as hexosomes. On the other hand, 2-HDM formed a lamellar liquid crystalline phase (smectic A) in thermotropic conditions, whereas multilamellar vesicles have been observed in equilibrium with aqueous media. Surprisingly, 2-HDM mixed with sodium dodecyl sulfate or aerosol OT induced the formation of more stable unilamellar vesicles. Thus, the branched-chain glycolipids 2-HDG and 2-HDM not only provided alternative nonionic surfactants with rich phase behavior and versatile nanostructures, but also could be used as new drug carrier systems in the future.

Investigation of the Effect of Sugar Stereochemistry on Biologically Relevant Lyotropic Phases from Branched-Chain Synthetic Glycolipids by Small-Angle X-ray Scattering

Synthetic branched-chain glycolipids are suitable as model systems in understanding biological cell membranes, particularly because certain natural lipids possess chain branching. Herein, four branched-chain glycopyranosides, namely, 2-hexyl-decyl-α-D-glucopyranoside (α-Glc-OC10C6), 2-hexyl-decyl-β-D-glucopyranoside (β-Glc-OC10C6), 2-hexyl-decyl-α-D-galactopyranoside (α-Gal-OC10C6), and 2-hexyl-decyl-β-D-galactopyranoside (β-Gal-OC10C6), with a total alkyl chain length of 16 carbon atoms have been synthesized, and their phase behavior has been studied. The partial binary phase diagrams of these nonionic surfactants in water were investigated by optical polarizing microscopy (OPM) and small-angle X-ray scattering (SAXS). The introduction of chain branching in the hydrocarbon chain region is shown to result in the formation of inverse structures such as inverse hexagonal and inverse bicontinuous cubic phases. A comparison of the four compounds showed that they exhibited different polymorphism, especially in the thermotropic state, as a result of contributions from anomeric and epimeric effects according to their stereochemistry. The neat α-Glc-OC10C6 compound exhibited a lamellar (Lα) phase whereas dry α-Gal-OC10C6 formed an inverse bicontinuous cubic Ia3d (QII(G)) phase. Both β-anomers of glucoside and galactoside adopted the inverse hexagonal phase (HII) in the dry state. Generally, in the presence of water, all four glycolipids formed inverse bicontinuous cubic Ia3d (QII(G)) and Pn3m (QII(D)) phases over wide temperature and concentration ranges. The formation of inverse nonlamellar phases by these Guerbet branched-chain glycosides confirms their potential as materials for novel biotechnological applications such as drug delivery and crystallization of membrane proteins.

Nanoemulsion as a topical delivery system of antipsoriatic drugs

Psoriasis is one of the most common skin diseases, affecting 2–5% of the worlds population. It is a skin autoimmune disorder, resulting in an excessive growth and aberrant differentiation of keratinocytes. Psoriasis is an incurable lifetime disease which can only be controlled and relieved through medication. Various approaches have been explored to treat the disease. Treatment of psoriasis includes topical therapy, systemic therapy and phototherapy. Topical therapy is the first line treatment and it is the most practical medication method for psoriasis patients. However, the conventional topical treatments such as gel and cream have low efficiency, poor cosmetic and aesthetic appeal, leading to poor patient compliance or adherence, while systemic and photo therapy produce significant adverse side effects. Nanoemulsion is defined as an emulsion system consisting of oil, surfactant, and water with an isotropic, transparent (or translucent) appearance. The emulsion droplet size is defined to be less than 200 nm. Nonetheless, if the emulsion has low surfactant content and is kinetically stable, a size of less than 500 nm can be accepted as nanoemulsion. A small droplet size would enhance the delivery and penetration of a drug through the psoriasis skin layer. There has been a growing interest in using nanoemulsions in topical applications, due to their high stability and their optical transparency or translucency, which make them good and very dermatologically attractive. A good selection of oils and surfactants would enhance the transdermal treatment efficacy. This review highlights the potential of drug-loaded nanoemulsions for the treatment of psoriasis towards achieving better efficacy and eliminating side effects.

Carbon nanofibers-poly-3-hydroxyalkanoates nanocomposite: ultrasound-assisted dispersion and thermostructural properties

The conductivity and high surface-to-volume ratio of carbon nanofibers (CNFs) composited with the medium-chain-length poly- 3-hydroxyalkanoate (mcl-PHA) have attracted much attention as smart biomaterial. However, poor CNF dispersion leads to tactoid agglomerated composite with poor crystallite morphology resulting in inferior thermomechanical properties. We employed acoustic sonication to enhance the construction of exfoliated PHA/CNFs nanocomposites. The effects of CNF loading and the insonation variables (power intensity, frequency, and time) on the stability and microscopic morphology of the nanocomposites were studied. Sonication improved the dispersion of CNFs into the polymer matrix, thereby improving the physical morphology, crystallinity, and thermomechanical properties of the nanocomposites. For example, compositing the polymer with 10% w/w CNF resulted in 66% increase in crystallite size, 46% increase in micromolecular elastic strain, and 17% increase in lattice strain. Nevertheless, polymer degradation was observed following the ultrasound exposure. The constructed bionanocomposite could potentially be applied for organic electroconductive materials, biosensors and stimuli-responsive drug delivery devices.

Synthesis, Characterization, and Anticancer Activity of New Quinazoline Derivatives against MCF-7 Cells

Two new synthesized and characterized quinazoline Schiff bases 1 and 2 were investigated for anticancer activity against MCF-7 human breast cancer cell line. Compounds 1 and 2 demonstrated a remarkable antiproliferative effect, with an IC50 value of 6.246 × 10−6 mol/L and 5.910 × 10−6 mol/L, respectively, after 72 hours of treatment. Most apoptosis morphological features in treated MCF-7 cells were observed by AO/PI staining. The results of cell cycle analysis indicate that compounds did not induce S and M phase arrest in cell after 24 hours of treatment. Furthermore, MCF-7 cells treated with 1 and 2 subjected to apoptosis death, as exhibited by perturbation of mitochondrial membrane potential and cytochrome c release as well as increase in ROS formation. We also found activation of caspases-3/7, -8, and -9 in compounds 1 and 2. Moreover, inhibition of NF-κB translocation in MCF-7 cells treated by compound 1 significantly exhibited the association of extrinsic apoptosis pathway. Acute toxicity results demonstrated the nontoxic nature of the compounds in mice. Our results showed significant activity towards MCF-7 cells via either intrinsic or extrinsic mitochondrial pathway and are potential candidate for further in vivo and clinical breast cancer studies.

Nano-delivery Systems for Nutraceutical Application

Nutraceutical is defined as a food or part of it that provides the body with medical or health benefits, including the prevention and treatment of a disease. It is seen as a more natural way to accomplish therapeutic results with minimal side effects, and this view has propelled the discovery and production of nutraceutical to become a multibillion dollar enterprise. Nanoparticle-based delivery system is one of the promising encapsulation technologies for the nutraceutical industry. It is comprised of liquid- and solid-delivery systems. Protection of food bioactives, storage stability, high loading capacity, bioactive sustainability, and controlled-release mechanism are sought after qualities offered by encapsulation technology. Solid nanodelivery system consists of three types of encapsulation viz. nanocrystal, lipid, and polymeric nanoparticles, whereas liquid nanodelivery system consists of nanovesicle and nanoemulsion. The chapter will discuss available nanoparticle-based delivery systems together with their development, characterization, and their potential as nutraceutical bioavailability enhancer.

Self-aggregation behavior of synthetic amphiphile derived from triazolylbenzoic acid: CMC and phase transition

An anionic surfactant with intention to mimic the natural fatty acids with highly conjugated component, has been synthesized and analyzed by using NMR, FTIR and MS. The polar head group of the structure was linked to the hydrophobic tail, through triazolyl moiety that was formed from the Cu(I) cycloaddition between an azidobenzoic acid and an acetylene. The critical micellar concentration (cmc) of the surfactant was determined at 0.1 mM by measuring its conductivity at a constant pH, consistent with the UV-Visible absorption. Phase transitions of the surfactant were then observed, by gradually decreasing the pH from 10 to 7. There were two stages of phase transitions observed at pH 8.9 and 7.6 upon titration, suggesting the transition from smaller to larger size of the aggregation structures. The results indicate that the aggregation mechanism of the synthesized surfactant w a s greatly influenced by the conversion of t h e head group from -COO− to -COOH, which is similar to the natural fatty acids in aqueous form.An anionic surfactant with intention to mimic the natural fatty acids with highly conjugated component, has been synthesized and analyzed by using NMR, FTIR and MS. The polar head group of the structure was linked to the hydrophobic tail, through triazolyl moiety that was formed from the Cu(I) cycloaddition between an azidobenzoic acid and an acetylene. The critical micellar concentration (cmc) of the surfactant was determined at 0.1 mM by measuring its conductivity at a constant pH, consistent with the UV-Visible absorption. Phase transitions of the surfactant were then observed, by gradually decreasing the pH from 10 to 7. There were two stages of phase transitions observed at pH 8.9 and 7.6 upon titration, suggesting the transition from smaller to larger size of the aggregation structures. The results indicate that the aggregation mechanism of the synthesized surfactant w a s greatly influenced by the conversion of t h e head group from -COO− to -COOH, which is similar to the natural fatty acids in aqu...