Preparation of Copper-loaded Microcapsule Formulations

Novel copper-loaded chitosan or chitosan/alginate based microcapsules formulations have been presented. It was shown that prolonged release of copper from microcapsules accompanied with possible prolonged presence of copper on leaves is useful in crop protection

Self-similarity of molecular association in double layers

Asocijacija molekula površinski aktivnih tvari (PAT), rast i agregacija samoasocijata u lamelarne dvoslojeve (fleksibilne i zatvorene), micele, vezikule i tekuće kristale, predstavljaju važna temeljna istraživanja s primjenom - između ostalog - na transmembranska svojstva vezikula u prijenosu i enkapsulaciji lijekova. Među mnogim praktičnim upotrebama amfifilni agregati predstavljaju mogućnost primjene dobro definiranih dvoslojeva i multislojeva liotropnih mezotaza za kozmetičku i faimaceutsku industriju. Asocijati katanionskih PAT pokazuju široku raznovrsnost oblika, veličina i strukture čestica pa je moguće proizvesti nove materijale različitih svojstava. Vezikule mogu nastajati spontano kao rezultat samo nakupljanja fleksibilnih monoslojeva u jednoslojne i višeslojne meke čestice sa zatvorenim dvoslojevima. U ovom radu istraživanja su provedena u katanionskim smjesama natrijevoga n dodecilbenzensulfonata (SDBS) i didodecildimetil amonijevoga bromida (DDAB) u vodi te u vodenim otopinama neionskoga dvolančanog PAT, 4-(l-pentilheptil)benzensulfonata (6SDBS). Određivanje faznoga dijagrama, područja stvaranja micela i vezikula te faznih prijelaza, određivanje unutarnjih i vanjskih struktura čestica, provedeno je s pomoću metode raspršenja svjetlosti, raspršenja X zraka pod malim kutom te drugih komplementarnih metoda, npr. reoloških mjerenja u pseudo-izotropnim područjima koja dobro indiciraju stvaranje micela i vezikula karakterizirano kritičnim micelizacijskim i vezikularnim koncentracijama. Dodatno, mezofaze su istraživane polarizacijskom i elektronskom mikroskopijom.Surfactant molecules association, growth and aggregation of selt associates into lamellar bilayers (flexible and closed), micelles, vesicles and liquid crystals, is considered to present important fundamental research with application to trans-membrane properties in the drug delivery and encapsulation. Among many practical applications, the amphiphilic aggregates present the possibility of using well defined bilayers and multilayers in the cosmetic and pharmaceutical industry. Associates of catanionic surfactants show a wide variety of particle shapes, sizes and structures, and due to that, the new materials of different properties could be prepared. Vesicles can be formed spontaneously as a result of self-association of flexible monolayers into unilamellar and multilamellar soft particles with closed bilayers. In this paper investigations have been performed in catanionic mixtures of Sodium n-dodecylbenzensulfonate (SDBS) and Didodecyldimetyl ammonium bromide (DDAB) in water, and in the water solutions of nonionic double-chain surfactant, 4-( 1 pentylheptyl)benzenesulfonate (6SDBS). Phase diagram, regions of micelles and vesicles formation, phase transitions, outer and inner structures of particles, were investigated by light scattering, small angle X-ray scattering, and other related methods, e.g., rheological measurements within pseudoisotropic regions that indicated the formation of micelles and vesicles as characterised by the critical micellisation and vesiculation concentrations. In addition, mesophases have been confirmed by polarisation and electron microscopy

Release of Trichoderma viride Spores from Microcapsules Simultaneously Loaded with Chemical and Biological Agents

Recent studies of bioactive agents, simultaneous encapsulation in chitosan/alginate microcapsules revealed that encapsulation in the same compartment does not inhibit activity either of Trichoderma viride spores nor copper cations. The objective of this work was to investigate the influence of formulation variables (concentration of copper cations, chitosan layer and microcapsule size) on T. viride spores release. Results showed that the increase in copper cation concentration promoted, but the increase in microcapsule size and presence of the chitosan layer on microcapsule surface reduced T. viride spores release. Fitting to simple Korsmeyer–Peppas empirical model elucidated the underlying mechanism of release. Fickian diffusion controlled release from microcapsules without chitosan layer and smaller microcapsules with chitosan layer, whereas anomalous diffusion mechanism (a combination of the diffusion and erosion mechanisms) was found to be the rate-controlling mechanism from larger microcapsules with chitosan layer. The investigation showed that proper selection of formulation variables helps in designing microcapsules with the desirable release of T. viride for plant protection and nutrition

Chitosan-based layer-by-layer edible coatings application for the preservation of mandarin fruit bioactive compounds and organic acids

The layer-by-layer application of biopolymeric coatings to mandarin fruits as a postharvest treatment to improve fruit coating efficacy has been reported. A single 1 % (w/v) chitosan application was evaluated, and polyelectrolyte complexes such as 1.5 % (w/v) alginate/chitosan, 1 % (w/v) hydroxypropyl methylcellulose/chitosan, and 0.2 % (w/v) locust bean gum/chitosan were applied to mandarin fruits. The quality of coated mandarin fruits was observed at temperatures: 20 ± 2 °C (up to 10 days) and 5 °C (up to 28 days). Changes in the fruit metabolism were observed by evaluating bioactive compounds (polyphenolic compounds and flavonoids), antioxidant activity, and organic acids during the preservation of mandarin fruits. All of the tested combinations of layer-by-layer coatings significantly impacted the quality of mandarin fruits throughout storage, both at room temperature and cold storage, respectively. The overall best performance was observed for a layer-by-layer hydroxypropyl methylcellulose/chitosan coating in terms of visual aspects, bioactive compounds, antioxidant activity, and organic acids content