Release Of Bioactive Materials Research Articles

Encapsulation of β-carotene from sea buckthorn (Hippophaë rhamnoides L.) juice in furcellaran beads

Abstract The objective of this study was to prepare and evaluate furcellaran beads as an encapsulation material for β-carotene from sea buckthorn ( Hippophae rhamnoides L.) juice. Beads were prepared by ionotropic gelation. The influence of bead formulation factors on the particle size and firmness was investigated and the encapsulation efficiency of β-carotene in beads was studied. The nature of the cation, the polymer and cation concentration, and the proportion of volumes of the outer to the inner phase influenced the size and firmness of furcellaran beads. With increasing proportion of sea buckthorn juice in the formulae, firmness of furcellaran beads decreased. The encapsulation efficiency of β-carotene from sea buckthorn juice in furcellaran capsules was 97%. It suggested that furcellaran beads may be applied for β-carotene encapsulation. Industrial relevance Encapsulation is a rapidly emerging area with multitude of applications in biotechnology, one of them being the controlled release of active biomolecules. The sensitivity to the environmental factors makes furcellaran a promising material for the controlled release of pharmaceuticals, (pro)biotica, and bioactive materials. Entrapment of these materials into the furcellaran beads by protecting them against degradation processes could solve the problem to incorporate health promoting ingredients into food without reducing their bioavailability or functionality. The change of pH in the digestive system could cause degradation of the beads followed by release of bioactive materials in the organism. It does create a basis for new product development in food industry. However, more work regarding to the improvements of bead stability and the release of entrapped materials are required.

Optimization study for the production of an opioid-like preparation from bovine casein by mild acidic hydrolysis

Abstract Several bioactive peptides (phosphopeptides, opioid peptides and immunopeptides) derived from milk proteins have been shown to exert beneficial effects, however only a few biologically active peptides from natural sources have found applications to date. In order to quantitatively produce opioid-like bioactive fragments from major milk proteins, the efficacy of a gastric-like digestive process to release casein-derived peptides that induce a myorelaxant effect, was investigated. Whole bovine casein was incubated with pepsin at low pH. The release of bioactive material occurred over time and correlated with the acidity rather than with the enzymatic activity. The acidic hydrolysate was tested for its opioid potencies in several conventional bioassay systems. It exhibited a naloxone-reversible inhibitory effect of the electrically evoked contractions of GPI, MVD and RVD. This opioid-like effect was estimated by the determination of the “apparent” IC50 values, and the antinociceptive efficacy confirmed in vitro.

Preparation and characterization of interpenetrating network beads of poly(vinyl alcohol)-grafted-poly(acrylamide) with sodium alginate and their controlled release characteristics for cypermethrin pesticidePreliminary results of this study were presented at the 28th International Symposium on Controlled Release of Bioactive Materials, Abstract No. 4001, June 23–27, 2001, San Diego, California.

Preparation and characterization of interpenetrating network beads of poly(vinyl alcohol)-grafted-poly(acrylamide) with sodium alginate and their controlled release characteristics for cypermethrin pesticidePreliminary results of this study were presented at the 28th International Symposium on Controlled Release of Bioactive Materials, Abstract No. 4001, June 23–27, 2001, San Diego, California.

LYMPHOTOXIN-β AND TNF REGULATION IN T CELL SUBSETS: DIFFERENTIAL EFFECTS OF PGE 2

The effects of prostaglandin E 2(PGE 2) on lymphotoxin β (LT-β) and tumour necrosis factor alpha (TNF) were assessed in murine CD4 +Th 1and Th 2T cell clones. LT-β mRNA was constitutively expressed by both T cell subsets. However, PGE 2inhibited its accumulation only in Th 1, but not Th 2clones. PGE 2inhibited TNF mRNA accumulation and production and release of bioactive material by both Th 1and Th 2T cells. The effects of PGE 2were also evaluated on production of IL-3, another cytokine produced by both T cell subsets, and interleukin 4 (IL-4), which is produced only by Th 2cells. Though IL-3 was produced by both T cell subsets it was only inhibited in Th 1cells, a pattern similar to that observed for LT-β. Accumulation of IL-4 mRNA in Th 2cells was not inhibited by PGE 2. These results demonstrate that PGE 2does not affect LT-β, IL-4, or IL-3 in Th 2cells, but inhibits TNF mRNA accumulation and production in this T cell subset. Thus, TNF appears to be the only cytokine susceptible to inhibition by PGE 2in Th 2cells. The fact that PGE 2inhibits LT-β and IL-3 in Th 1but not Th 2cells points to a different mechanism of regulation of the same cytokine in different subsets. The mechanisms that contribute to TNF mRNA accumulation also may differ in the two CD4 +T cell subsets, because cycloheximide superinduced TNF mRNA in Th 2cells, but not in Th 1cells. The inhibitory effects of PGE 2on TNF mRNA accumulation by either T cell subset did not require de novoprotein synthesis since preincubation with the protein synthesis inhibitor, cycloheximide, did not alter the PGE 2-mediated effects. Cross-regulation of cytokine production and function has been demonstrated for both T cell subsets, and PGE 2may modulate the outcome of an immune response via differential regulation of cytokine production.

Polyethylene-starch extrudates as erodible carriers for bioactive materials: I. Erodibility and in vitro dye release studies.

The objective of the present investigation is to develop and evaluate polyethylene-starch based carriers for sustaining the release of bioactive materials. Polyethylene-starch carriers were prepared by incorporating various amounts of corn starch 0, 40, 80, and 100% in polyethylene beads with and without dye. Acid orange dye was incorporated (1%) to study release patterns and the effect of starch (%) on release. The granulated mixtures were extruded to form uniform dispersions of starch and polyethylene throughout the extrudate. The extrudates obtained were studied for SEM surface characterization before, during, and after release studies to study the erosion process. In the case of 100% starch, 80% of the matrix was eroded in 5 weeks, while with 40% and 80% starch, erosion was less than 20%. The dye release studies showed that release could be sustained well over 12 weeks, depending on the starch (%) incorporated. The erosion process was studied using scanning electron microscopic techniques, which showed gradual erosion of starch particles, leaving a polyethylene skeleton. These materials show promising potential for use as carriers for bioactive materials.

21st international symposium on controlled release of bioactive materials

21st international symposium on controlled release of bioactive materials

Bioactive materials for antifouling coatings

Marine fouling is the result of the settling and subsequent growth of marine organisms on surfaces immersed in seawater. The most successful principle in use today for the protection of ship's hulls against this unwanted growth is the release of bioactive materials from antifouling coatings. Antifouling coatings containing a mixture of cuprous oxide and triorganotin compounds in combination with sophisticated release mechanisms are considered to be today's most efficient systems. However, ever since the first biologically active materials were introduced into antifouling coatings, a search for alternatives has been continuing. Until the mid-1970s this research mainly involved the development of biocides which could simply prolong existing drydocking intervals, i.e. prolong the period in which the ship was fouling free. During the last decade, however, environmental aspects have become a top priority in the development of new biocides for antifouling coatings.

11th international symposium on controlled release of bioactive materials

11th international symposium on controlled release of bioactive materials