Recent Advances in the Microencapsulation of Essential Oils, Lipids, and Compound Lipids through Spray Drying: A Review.

In recent decades, the microcapsules of lipids, compound lipids, and essential oils, have found numerous potential practical applications in food, textiles, agricultural products, as well as pharmaceuticals. This article discusses the encapsulation of fat-soluble vitamins, essential oils, polyunsaturated fatty acids, and structured lipids. Consequently, the compiled information establishes the criteria to better select encapsulating agents as well as combinations of encapsulating agents best suited to the types of active ingredient to be encapsulated. This review shows a trend towards applications in food and pharmacology as well as the increase in research related to microencapsulation by the spray drying of vitamins A and E, as well as fish oil, thanks to its contribution of omega 3 and omega 6. There is also an increase in articles in which spray drying is combined with other encapsulation techniques, or modifications to the conventional spray drying system.

5-Fluorouracil drug delivery system based on bacterial nanocellulose for colorectal cancer treatment: Mathematical and in vitro evaluation.

Colorectal cancer (CRC) is the third most common worldwide. Its treatment includes adjuvant chemotherapy with 5-fluorouracil (5FU) administered intravenously. 5FU is an antineoplastic drug of the fluoropyrimidines group, widely used in the treatment of solid tumors, mainly CRC. Nevertheless, it causes several adverse effects and poor effectiveness due to its short half-life. This work aimed to employ bacterial nanocellulose (BNC) as an encapsulation material for the oral administration of 5FU. First, the adsorption phenomena were analyzed by isotherms, thermodynamic parameters, and kinetic models. Then, encapsulation was carried out using spray-drying, and encapsulated 5FU desorption profiles were assessed in simulated fluids. The biological behavior was evaluated on colon cancer SW480 and SW620 cell lines. As result, it was found that at 25 °C a monolayer of 5FU was formed and the process showed to be the most spontaneous one. In the characterization of the nanocapsules, important changes were detected by the presence of 5FU. The delivery in the colon corresponded to a controlled release behavior. The in vitro assay indicated an improvement in the toxicity effect of the drug and its mechanism of action. Accordingly, BNC is a promising biomaterial for the development of a colon drug delivery platform of 5FU.

Effects of Chemical Post-treatments on Structural and Physicochemical Properties of Silk Fibroin Films Obtained From Silk Fibrous Waste.

Silk fibroin (SF) is a protein polymer claimed to have outstanding potential for medical applications. However, because of the manufacturing process, materials from regenerated SF exhibit a higher percentage of amorphous structures. The amorphous structures cause the material to be water soluble and can significantly limit its applications in wet biological environments. In order to increase the amount of crystalline structures and decrease the water solubility of SF materials, post-treatment with alcohols is usually employed. SF can be obtained from silk fibrous wastes (SFW), usually discarded in silk textile processes. This represents an opportunity to produce materials with high added value from low-cost natural sources. In this study, SF was obtained from SFW, and films were made thereof followed by a post-treatment by immersion or in a saturated atmosphere of methanol (MeOH) or ethanol (EtOH), using different exposure times. The resulting films were analyzed according to crystallinity, the percentage of crystalline and amorphous structures, and thermal stability. Also, water absorption and weight loss in aqueous media were determined. The results showed a significant increase in crystalline structures in all treated samples, varying according to the type and time of exposure to post-treatment conducted. The highest increase was shown in the case of the post-treatment by immersion in MeOH for 1 h, with a 23% increase over the untreated sample. This increase in crystallinity was reflected in an increase in the degradation temperature and a degradation rate of 5.3% on day 7. The possibility of tuning the degree of crystallinity, as well as thermal stability and aqueous integrity of thin films of SFW, can be applied to adjust these materials to the requirements of specific biomedical applications.