Preparation and characterization of octenyl succinic anhydride modified waxy maize starch hydrolyzate/chitosan complexes with enhanced interfacial properties.

The preparation and characterization of colloidal complexes based on octenyl succinic anhydride starch hydrolyzate (OSAS) and chitosan (CS) were conducted. Results showed that OSA-S/CS ratio (r) and pH significantly affected complex turbidities and yields. The highest turbidity and yield were obtained at r = 6:1 when pH was fixed, and at pH 6.5 when r was fixed. All complexes remained liquid-like except that formed at pH 6.5, which exhibited a gel structure due to the strongest complexation. OSA-S/CS complexes had intertwined core-shell microstructure and exhibited electrostatic interactions between COO- and NH3+ groups of OSA-S and CS, respectively. The complexes prepared at r = 6:1 and pH 6.0 exhibited the most suitable wettability (θow = 91.97°) and interfacial adsorption dynamics. The compact lamellar network and intact cores of these complexes were also shown. This work provides profound and comprehensive information about the formation and physicochemical properties of OSA-S/CS complexes.

Water-mediated catalyst-free synthesis of lysine-based ampholytic amphiphiles for multipurpose applications: Characterization and pH-responsive emulsifying properties.

A novel series of lysine-based ampholytic amphiphiles, with alkylsuccinic anhydrides of varying chain lengths as hydrophobic acylating agents, were synthesized in medium to high yield (50.23-90.15%) based on a facile, catalyst-free method in water medium; and structurally confirmed by mass spectrometry (MS), Fourier transform infra-red (FTIR) spectroscopy, and 1H/13C nuclear magnetic resonances (NMR) analysis. The resulting compounds were subjected to pH-dependent amphiphilic property, ferrous ion chelating, DPPH antioxidant capacity, and cytotoxicity analyses. Results showed that CMC values decrease, γ value increase, and emulsion stability increase with the increase of medium pH, suggesting that the surface activity of synthetic compounds at air/water and oil/water interface under neutral and alkaline conditions was remarkably higher than that under acidic condition. Lauryl O-acylated malic lysine (compound 4b) presented excellent foaming ability close to commercial detergent sodium dodecyl sulphate; dodecyl succinic lysine (compound 4a) afforded highly stable o/w nanoemulsion. Moreover, compound 4b displayed comparable ferrous ion chelating property to lysine and 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidative capacity similar to a commercial food ingredient, diacetyl tartaric acid esters of mono- and di-glycerides (DATEM), indicating its multi-faceted functionalities. A cytotoxicity study of compounds 3b &4b showed that they were non-toxic. Thus, these novel ampholytic amphiphiles may find multi-purpose applications in food, detergent, pharmaceutical, and cosmetic industry.

Synthesis of d-labeled and unlabeled ethyl succinic anhydrides and application to quantitative analysis of peptides by isotope differential mass spectrometry.

Ethyl succinic anhydride and its d5-labeled version have been synthesized and applied to quantitative analysis of peptides in combination with MALDI or ESI mass spectrometry. These modifiers react with amino groups in the N-termini and lysine side chains in proteins, and therefore the combination of these modifiers was shown to be a useful tool for quantification of peptides and hence for proteomics research.

Preparation of fenofibrate dry emulsion and dry suspension using octenyl succinic anhydride starch as emulsifying agent and solid carrier.

Purpose of this study was to investigate the ability of octenyl succinic anhydride (OSA) starch as emulsifier and solid carrier in dry emulsion (DE) and dry suspension (DS) formulations. Fenofibrate (FF) was loaded at lower and higher than its saturation concentration in oil phase to prepare the DE and DS by spray drying method. The DE and DS were successfully prepared with 36-48% and 46% production yield, respectively. After reconstitution in water, the emulsion with mean droplet size of 1-2 µm was obtained. Solid state characterization revealed the amorphous state of FF and the crystalline state of OSA starch in both DE and DS formulations. Both DE and DS enhanced FF dissolution rate compared to pure material and DS showed the highest dissolution rate. The DE and DS could be compressed to the tablets with acceptable disintegration time and without changeable dissolution profile. Moreover, the dissolution profiles of both DE and DS remained unchanged after 2 months storage at 40 °C.

A facile synthesis of deuterium labeled 2,2-dimethyl-[2H6]-succinic acid and its anhydride.

Deuterium labeled 2,2-dimethyl-[(2)H(6)]-succinic anhydride by a sequence of reactions involving Knoevenagel condensation of [(2)H(6)]-acetone with ethyl cyanoacetate in the presence of piperidine, Michael addition of cyanide, HCl hydrolysis, simultaneous decarboxylation, and subsequent dehydration using acetic anhydride in an overall yield of 34.23% based on [(2)H(6)]-acetone utilized in the reaction is reported. The title compounds were characterized and confirmed spectroscopically by Fourier transform infrared, (1) H-NMR, and Mass. The chemical purity as determined by HPLC was 99%. To the best of our knowledge, the synthesis of these specifically deuterium labeled compounds has not been reported so far.

Monoglyceride-based self-assembling copolymers as carriers for poorly water-soluble drugs.

To develop self-assembling polymers forming polymeric micelles and increasing the solubility of poorly soluble drugs, amphiphilic polymers containing a hydrophilic PEG moiety and a hydrophobic moiety derived from monoglycerides and polyethers were designed. The biodegradable copolymers were obtained via a polycondensation reaction of polyethylene glycol (PEG), monooleylglyceride (MOG) and succinic anhydride (SA). Polymers with molecular weight below 10,000 g/mol containing a minimum of 40 mol% PEG and a maximum of 10 mol% MOG self-assembled spontaneously in aqueous media upon gentle mixing. They formed particles with a diameter of 10 nm although some aggregation was evident. The critical micellar concentration varied between 3x10(-4) and 4x10(-3) g/ml, depending on the polymer. The cloud point (> or = 66 degrees C) and flocculation point (> or = 0.89 M) increased with the PEG chain length. At a 1% concentration, the polymers increased the solubility of poorly water-soluble drug candidates up to 500-fold. Drug solubility increased as a function of the polymer concentration. HPMC capsules filled with these polymers disintegrated and released model drugs rapidly. Polymer with long PEG chains had a lower cytotoxicity (MTT test) on Caco-2 cells. All of these data suggest that the object polymers, in particular PEG1000/MOG/SA (45/5/50) might be potential candidates for improving the oral biopharmaceutical performance of poorly soluble drugs.

Production of octenyl succinic anhydride-modified waxy corn starch and its characterization.

The objective of this work is to investigate the effects of reaction conditions on the synthesis of octenyl succinic anhydride (OSA)-modified starch from waxy corn starch and to study the characteristics of the OSA-modified starch as well as its applications. A mathematical model was developed to investigate the influences of various processing condition factors on the production of the OSA-modified waxy corn starch production and predict the optimum reaction conditions. The maximal degree of substitution (DS) of OSA-modified waxy corn starch (0.0204) was predicted to occur when the starch concentration was 31.2%, the pH was 8.6, the reaction temperature was 33.6 degrees C, and the reaction time was 18.7 h. Repeated reactions for producing OSA-modified waxy corn starch were carried out in a 5 m(3) reactor under the optimized conditions for verification of the model. The characteristics of modified waxy corn starch including infrared spectrum, scanning electron microscopy, and pasting property were tested and emulsification capacity of the OSA-modified starch were evaluated as well.

Formation of shellac succinate having improved enteric film properties through dry media reaction.

The aim of this study was to improve enteric properties of shellac by the formation of succinate derivative through dry media reaction. Shellac and succinic anhydride were mixed and then co-ground by planetary ball mill. The ground mixture was then activated by heating for various times and washed for removal of excess succinic anhydride. The ground mixtures and the heat-activated mixtures were characterized by physical and chemical tests, including acid value, FTIR spectroscopy, (1)H NMR and (13)C NMR spectroscopy, thermal analysis and film properties. The results demonstrated that acid values of heat-activated shellac mixtures increased with the increase of annealing time, suggesting the presence of carboxylic acid moieties of succinate at shellac molecules. The results were in good agreement with the DSC thermograms. The melting peak of shellac disappeared after heating, while melting peak of succinic anhydride gradually decreased, suggesting the utilization of succinic anhydride for the esterification. The shellac succinate formation was also confirmed by (1)H NMR and (13)C NMR spectroscopies. Film prepared from shellac succinate showed improved solubility, especially at the pH of small intestine (5.8-6.7), as compared to native shellac. The shellac succinate film also demonstrated better mechanical property, in terms of increased flexibility. In conclusion, solid-state formation of shellac succinate ester, which had improved enteric properties, was easily accomplished under the concept of "green approach".