Physico-chemical characterization of zein as a film coating polymer: A direct comparison with ethyl cellulose

pH Effect on the Structure, Rheology, and Electrospinning of Maize Zein

As a simple and convenient technology to fabricate micron-to-nanoscale fibers with controllable structure, electrostatic spinning has produced fiber films with many natural advantages, including a large specific surface area and high porosity. Maize zein, as a major storage protein in corn, showed high hydrophobicity and has been successfully applied as a promising carrier for encapsulation and controlled release in the pharmaceutical and food areas. Proteins exhibit different physical and chemical properties at different pH values, and it is worth investigating whether this change in physical and chemical properties affects the properties of electrospun fiber films. We studied the pH effects on zein solution rheology, fiber morphology, and film properties. Rotational rheometers were used to test the rheology of the solutions and establish a correlation between solution concentration and fiber morphology. The critical concentrations calculated by the cross-equation fitting model were 17.6%, 20.1%, 20.1%, 17.1%, and 19.5% (w/v) for pH 4, 5, 6, 7, and 8, respectively. The secondary structure of zein changed with the variation in solution pH. Furthermore, we analyzed the physical properties of the zein films. The contact angles of the fiber membranes prepared with different pH spinning solutions were all above 100, while zein films formed by solvent evaporation showed hydrophilic properties. The results indicated that the rheological properties of zein solutions and the surface properties of the film were affected by the pH value. This study showed that zein solutions can be stabilized to form electrospun fibers at a variety of pH levels and offered new opportunities to further enhance the encapsulation activity of zein films for bioactive materials.

In vitro Investigation of the Antimicrobial Activity of Mouth Washes Incorporating Zein-Coated Magnesium Oxide Nanoparticles

PURPOSE

This in vitro study was undertaken to investigate the antimicrobial effect of distinctive oral mouth washes after the addition of zein-coated (Magnesium oxide) MgO nanoparticles on exemplary of some oral microorganisms.

MATERIALS AND METHODS

Three hundred and twelve samples were used in this study. A set of five concentrations of MgO nanoparticles with zein and without zein-coating were incorporated into three oral mouth washes: Listerine zero, Listerine total control and Oral B in the mass percentages of 0.3%, 0.5%, 1%, 2%, 5% and 10%, in addition to controls with no MgO nanoparticles. The antimicrobial effect of three mouth washes with variable concentrations of MgO was tested against the following organisms: Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis and Candida albicans using the disc diffusion test (DDT) and direct contact test (DCT). Data were analyzed using one-way ANOVA statistical test.

RESULTS

The tested mouthwashes with zein-coated MgO nanoparticles showed significant differences of antimicrobial activity on S. mutans, S. aureus, E. faecalis, and C. albicans in the disc diffusion test. While in the DCT, all tested mouthwashes with MgO nanoparticles with and without zein coating showed antimicrobial activity on all tested microorganisms.

CONCLUSION

Zein-coated MgO nanoparticles may be considered as a potential antimicrobial agent when added to oral mouthwashes. Future analysis, including in vivo studies, is required in order to incorporate zein/MgO nanoparticles into oral mouthwashes that may improve its antibacterial property.

The Use of Natural Materials in Film Coating for Controlled Oral Drug Release

BACKGROUND

Although synthetic materials have been used in film coating processes for drug delivery for many years, substantial studies on natural materials have also been conducted because of their biodegradable and unique properties.

METHODS

Because of the ability to form and modify films for controlled oral drug delivery, increasing attention has been shown to these materials in the design of film coating systems in recent research.

RESULTS

This review aims to provide an overview of natural materials focusing on film coating for oral delivery, specifically in terms of their classification and their combinations in film coating formulations for adjusting the desired properties for controlled drug delivery.

CONCLUSIONS

Discussing natural materials and their potential applications in film coating would benefit the optimization of processes and strategies for future utilization.

Hot melt extruded zein for controlled delivery of diclofenac sodium: Effect of drug loading and medium composition

This study evaluates the potential use of zein as an excipient in hot-melt extrusion for controlled delivery of diclofenac sodium (DS). Mixtures of zein, polyethylene glycol and drug were hot melt extruded and cut into 2 mm extrudates. Extrudates were characterised using differential scanning calorimetry, X-ray powder diffraction and scanning electron microscopy. The drug in the extrudates was found to be in the non-crystalline state, independent of the drug loading. Moreover, the drug release from extrudates was investigated. The release was directly dependent on the drug loading: a controlled and nearly zero-order release was obtained at the lowest drug loading (12.5% w/w), whereas almost immediate release was achieved at higher drug loadings, i.e. 25% and 37.5%. The release was inversely dependent on the ionic strength of the medium. The influence of digestive enzymes on drug release was also studied. Pancreatin, but not pepsin, was found to have a significant influence on the drug release as well as on the microstructure of zein extrudates. These data therefore support the potential use of zein as excipient in hot melt extrusion for controlled release purposes.

Application of Protein-Based Films and Coatings for Food Packaging: A Review

As the IV generation of packaging, biopolymers, with the advantages of biodegradability, process ability, combination possibilities and no pollution to food, have become the leading food packaging materials. Biopolymers can be directly extracted from biomass, synthesized from bioderived monomers and produced directly by microorganisms which are all abundant and renewable. The raw materials used to produce biopolymers are low-cost, some even coming from agrion dustrial waste. This review summarized the advances in protein-based films and coatings for food packaging. The materials studied to develop protein-based packaging films and coatings can be divided into two classes: plant proteins and animal proteins. Parts of proteins are referred in this review, including plant proteins i.e., gluten, soy proteins and zein, and animal proteins i.e., casein, whey and gelatin. Films and coatings based on these proteins have excellent gas barrier properties and satisfactory mechanical properties. However, the hydrophilicity of proteins makes the protein-based films present poor water barrier characteristics. The application of plasticizers and the corresponding post-treatments can make the properties of the protein-based films and coatings improved. The addition of active compounds into protein-based films can effectively inhibit or delay the growth of microorganisms and the oxidation of lipids. The review also summarized the research about the storage requirements of various foods that can provide corresponding guidance for the preparation of food packaging materials. Numerous application examples of protein-based films and coatings in food packaging also confirm their important role in food packaging materials.

Zein as a Pharmaceutical Excipient in Oral Solid Dosage Forms: State of the Art and Future Perspectives

Zein is the main storage protein of corn and it has several industrial applications. Mainly in the last 10-15 years, zein has emerged as a potential pharmaceutical excipient with unique features. Zein is a natural, biocompatible and biodegradable material produced from renewable sources. It is insoluble, yet due to its amphiphilic nature, it has self-assembling properties, which have been exploited for the formation of micromicroparticle and nanoparticle and films. Moreover, zein can hydrate so it has been used in swellable matrices for controlled drug release. Other pharmaceutical applications of zein in oral drug delivery include its incorporation in solid dispersions of poorly soluble drugs and in colonic drug delivery systems. This review describes the features of zein significant for its use as a pharmaceutical excipient for oral drug delivery, and it summaries the literature relevant to macroscopic zein-based oral dosage forms, i.e. tablets, capsules, beads and powders. Particular attention is paid to the most novel formulations and applications of zein. Moreover, gaps of knowledge as well as possible venues for future investigations on zein are highlighted.

Recent advances in food-packing, pharmaceutical and biomedical applications of zein and zein-based materials

Zein is a biodegradable and biocompatible material extracted from renewable resources; it comprises almost 80% of the whole protein content in corn. This review highlights and describes some zein and zein-based materials, focusing on biomedical applications. It was demonstrated in this review that the biodegradation and biocompatibility of zein are key parameters for its uses in the food-packing, biomedical and pharmaceutical fields. Furthermore, it was pointed out that the presence of hydrophilic-hydrophobic groups in zein chains is a very important aspect for obtaining material with different hydrophobicities by mixing with other moieties (polymeric or not), but also for obtaining derivatives with different properties. The physical and chemical characteristics and special structure (at the molecular, nano and micro scales) make zein molecules inherently superior to many other polymers from natural sources and synthetic ones. The film-forming property of zein and zein-based materials is important for several applications. The good electrospinnability of zein is important for producing zein and zein-based nanofibers for applications in tissue engineering and drug delivery. The use of zein's hydrolysate peptides for reducing blood pressure is another important issue related to the application of derivatives of zein in the biomedical field. It is pointed out that the biodegradability and biocompatibility of zein and other inherent properties associated with zein's structure allow a myriad of applications of such materials with great potential in the near future.

Zein in controlled drug delivery and tissue engineering

Controlled delivery of a bioactive to specific organ, cellular and sub-cellular level is a desired feature of a drug carrier system. In order to achieve this goal, formulation scientists search for better alternatives of biomaterials to deliver the therapeutics in more precise and controlled manner in vivo. Zein, a plant protein obtained from corn, is a useful biomaterial for several industrial applications including agriculture, cosmetics, packaging and pharmaceuticals. Being a hydrophobic protein, which is biodegradable, biocompatible, economic to use and with generally regarded safe "GRAS" status, it is an attractive biomaterial for human use. Novel biomedical applications of zein such as controlled and targeted delivery of bioactives and tissue engineering are the current research interests of the scientific fraternity. Here we attempt to review the literature on zein as a biopolymer for drug/vaccine/gene delivery and its applicability in tissue engineering.

Thermoplastic Foams from Zein and Gelatin

The aim of this study was to characterize the foaming of natural proteins as thermoplastic polymers. In particular, two proteins, one of vegetal origin, zein, and one of animal origin, gelatin, were processed to achieve thermoplastic polymers, and subsequently foamed by a gas foaming batch process. The effects of suitable plasticizing additives and melt-mixing process on the thermal and mechanical properties of the thermoplasticized proteins were evaluated to assess the thermoplastic characteristics of these materials. Furthermore, selected protein/plasticizers systems were foamed with mixtures of CO2 and N2 as blowing agents, in a batch foaming apparatus, at different temperatures, pressures and pressure drop rates, to evaluate the processing window and the final properties of the foams. Foams with densities of 0.1 g/cm3 and morphologies characterized by uniform distributions of cells with 10 μm diameters were obtained. Results indicated the suitability of zein and gelatin for being processed with classical thermoplastic processing technologies including melt mixing and foaming and their potentials as biodegradable polymers.