Active packaging is an innovative strategy in preventing lipid oxidation. Different active substances with different mechanisms of action have been investigated for imparting antioxidant activity to active packaging systems, including free radical scavengers, metal chelators, ultraviolet (UV) absorbers, oxygen scavengers, and singlet oxygen quenchers. Antioxidant agents have been incorporated into active packaging systems in different forms, mainly including independent sachet packages, adhesive-bonded labels, physical adsorption/coating on packaging material surface, being incorporated into packaging polymer matrix, multilayer films, and covalent immobilization onto the food contact packaging surface. In this paper, we review recent advances in antioxidant active packaging with the highlight of the development and application of non-migratory active packaging systems. The potential use of emerging technologies in antioxidant active packaging is also emphasized. We further describe challenges and opportunities towards the commercial application of such antioxidant active packaging systems, with a focus on maintaining safety, quality and nutrition of packaged foods.

Objectives To provide a comprehensive understanding of the competing thermodynamic and kinetic factors governing the crystallization of various hydrate systems. The ultimate goal is to utilize this understanding to improve the control over the unit operations involving hydrate formation, as well as to optimize the bioavailability of a given drug product. Key findings The thermodynamic and kinetic factors that govern hydrate crystallization are introduced and the current status of the endeavour to gain a mechanistic understanding of the phenomena that occur during the crystallization of different hydrate systems is discussed. The importance of hydrate investigation in the pharmaceutical field is exemplified by examining two specific hydrate systems: the polymorphic hydrate system and hydrates of pharmaceutical salts. Summary This review identifies the factors that are of critical importance in the investigation of anhydrate/hydrate systems. This knowledge can be used to control the phase transformation during pharmaceutical processing and storage, as well as in building a desired functionality for the final formulation.

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The influence of various excipients on the conversion of carbamazepine polymorphs to the dihydrate in aqueous suspension has been investigated. Ten excipients having functional groups which were potentially able to form hydrogen bonds with carbamazepine (group 1: methylcellulose, hypromellose (hydroxypropyl methylcellulose), hydroxypropylcellulose (HPC), 2-hydroxyethylcellulose (HEC), carmellose sodium (sodium carboxymethylcellulose), cellobiose; group 2: povidone (polyvinylpyrrolidone), povidone-vinyl acetate copolymer (povidone/VA) and N-methyl-2-pyrrolidone; group 3: macrogol (polyethylene glycol) and polyethylene oxide-polypropylene oxide copolymer (PEO/PPO)) were selected. Carbamazepine polymorphic forms III and I were dispersed separately into each aqueous excipient solution (0.1%, w/v) for 30 min at room temperature. The inhibition effect of each excipient was quantified using Raman spectroscopy combined with multivariate analyses. The solubility parameter of each excipient was calculated and used for categorizing excipients. Excipients in groups 1 and 2, which had both low solubility parameters (< 27.0 MPa(1/2)) and strong hydrogen bonding groups, inhibited the conversion completely. With increasing solubility parameter, the inhibition effect decreased for group 1 excipients, especially for carbamazepine form I, which had a higher specific surface area. Also, the excipients of group 3, lacking strong hydrogen bonding groups, showed poor inhibition although they had low solubility parameters (< 21.0 MPa(1/2)). This study indicated the importance of both hydrogen bonding interaction and a suitable hydrophobicity (expressed by the solubility parameter) in the inhibition of the conversion of carbamazepine to the dihydrate.

The genetic diversity of siderophore-producing bacteria of tobacco rhizosphere was studied by amplified ribosomal DNA restriction analysis (ARDRA), 16S rRNA sequence homology and phylogenetics analysis methods. Studies demonstrated that 85% of the total 354 isolates produced siderophores in iron limited liquid medium. A total of 28 ARDRA patterns were identified among the 299 siderophore-producing bacterial isolates. The 28 ARDRA patterns represented bacteria of 14 different genera belonging to six bacterial divisions, namely β-, γ-, α-Proteobacteria, Sphingobacteria, Bacilli, and Actinobacteria. Especially, γ-Proteobacteria consisting of Pseudomonas, Enterobacter, Serratia, Pantoea, Erwinia and Stenotrophomonas genus encountered 18 different ARDRA groups. Results also showed a greater siderophore-producing bacterial diversity than previous researches. For example, Sphingobacterium (isolates G-2-21-1 and G-2-27-2), Pseudomonas poae (isolate G-2-1-1), Enterobacter endosymbiont (isolates G-2-10-2 and N-5-10), Delftia acidovorans (isolate G-1-15), and Achromobacter xylosoxidans (isolates N-46-11HH and N-5-20) were reported to be able to produce siderophores under low-iron conditions for the first time. Gram-negative isolates were more frequently encountered, with more than 95% total frequency. For Gram-positive bacteria, the Bacillus and Rhodococcus were the only two genera, with 1.7% total frequency. Furthermore, the Pseudomonas and Enterobacter were dominant in this environment, with 44.5% and 24.7% total frequency, respectively. It was also found that 75 percent of the isolates that had the high percentages of siderophore units (% between 40 and 60) belonged to Pseudomonas. Pseudomonas sp. G-229-21 screened out in this study may have potential to apply to low-iron soil to prevent plant soil-borne fungal pathogen diseases.

Traditional dissolution testing determines drug release to the bulk, but does not enable an understanding of the events happening close to the surface of a solid or a tablet. UV imaging is a new imaging approach that can be used to study the dissolution behavior of chemical compounds. The UV imaging instrumentation offers recording of absorbance maps with a high spatial and temporal resolution which facilitates the abundant collection of information regarding the evolving solution concentrations. In this study, UV imaging was used to visualize the dissolution behavior of amlodipine besylate (amorphous and dihydrate forms) and amlodipine free base. The dissolution of amlodipine besylate was faster from the amorphous form than from the crystalline forms. The UV imaging investigations suggested that a solvent mediated phase transformation occurred for the amorphous amlodipine besylate and the amlodipine free base samples. Raman spectroscopy was used to confirm and probe the changes at the solid surface occurring upon contact with the dissolution media and verified the recrystallization of the amorphous form to the monohydrate. The combination of UV imaging and Raman spectroscopy is an efficient tool to obtain a deeper insight into the early events of the dissolution process.

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Transition metal-promoted oxidation impacts the quality, shelf life, and nutrition of many packaged foods. Metalchelating active packaging therefore offers a means to protect foods against oxidation. Herein, we report the development and characterization of nonmigratory metal-chelating active packaging. To prepare the films, carboxylic acids were grafted onto the surfaces of polypropylene films by photoinitiated graft polymerization of acrylic acid. Attenuated total reflectance/Fourier transform infrared spectroscopy, contact angle, scanning electron microscopy, and iron-chelating assay were used to characterize film properties. Graft polymerization yielded a carboxylic acid density of 68.67 ± 9.99 nmol per cm 2 film, with ferrous ironchelating activity of 71.07 ± 12.95 nmol per cm 2 . The functionalized films extended the lag phase of lipid oxidation in a soybean oil-in-water emulsion system from 2 to 9 days. The application of such nonmigratory active packaging films represents a promising approach to reduce additive use while maintaining food quality.