Effect of process variables on particle size and viability of Bifidobacterium lactis Bb-12 in genipin-gelatin microspheres

Gelatin microspheres cross-linked with genipin were developed to encapsulate the probiotic Bifidobacterium lactis Bb-12 The effects of different gelatin concentrations (10–19% w/v), bloom strengths (175 and 300), surfactants, stirring rates during emulsion formation and genipin concentrations (0–10?mM) on the microsphere sizes and viability of bacterial cells were investigated. Principal Component Analysis revealed microsphere size distribution differed depending on the presence or absence of surfactants as well as a trend of increasing micropshere size with increasing gelatin concentration and bloom strength. Lower stirring rates resulted in larger microspheres with higher encapsulation yields of bifidobacteria Microsphere size and cell viability were not significantly (p?<?0.05) influenced by increasing genipin concentrations up to 10?mM whereas microsphere stability in simulated gastric juice increased with increasing genipin concentration. The encapsulation yields were higher in 175 bloom strength gelatin microspheres than in 300. Cold-stage scanning electron microscopy showed encapsulated bacteria distributed throughout the genipin cross-linked gelatin matrix.     

In vitro survival of Bifidobacterium bifidum microencapsulated in zein-coated alginate hydrogel microbeads

The Bifidobacterium bifidum susceptibility in gastrointestinal conditions and storage stability limit its use as potential probiotics. The current study was design to encapsulate B. bifidum using sodium alginate (SA, 1.4% w/v) and different concentration of zein as coating material, that is, Z₁ (1% w/v), Z₂ (3% w/v), Z₃ (5% w/v), Z₄ (7% w/v), Z₅ (9% w/v). The resultant microbeads were further investigated for encapsulation efficiency, survival in gastrointestinal conditions, release profile in intestinal fluid, storage stability and morphological characteristics. The highest encapsulation efficiency (94.56%) and viable count (>10⁷ log CFU/g) was observed in Z₄ (7% w/v). Viable cell count of B. bifidum was >10⁶ log CFU/g in all the zein-coated microbeads as compare to free cells (10³ log CFU/g) and SA (10⁵ log CFU/g) at 4 °C after 32 days of storage. Therefore, B. bifidum encapsulated in zein-coated alginate microbeads present improved survival during gastric transit and storage.     

Microentrapment of probiotic bacteria in a Ca2 +-induced whey protein gel and effects on their viability in a dynamic gastro-intestinal model

Entrapping probiotic bacteria in gels with ionic cross-linking is typically achieved with polysaccharides (alginate, pectin, carraghenan). In this study, whey proteins were used for this purpose by carrying out the Ca²⁺-induced gelation of pre-heated whey protein isolate (WPI). A Lactobacillus rhamnosus cell suspension was added in a denatured WPI solution in a 30?:?70 volume ratio. Gelation was carried out by extrusion of the cell suspension in a CaCl₂ solution. Beads of ～3?mm diameter were formed. The population in the beads was 8.0?×?10⁸?cells?g^?1. Entrapment efficiency in gel beads was 96%, with a survival level of 23%. Scanning electron microscopy of beads before freeze-drying showed a tight protein network containing encapsulated Lb. rhamnosus cells homogeneously distributed throughout the matrix. The survival to freeze-drying of the bead-entrapped cells was 41%. Viability of microentrapped cells in a dynamic gastro-intestinal (GI) model was studied and the results were compared to free cells freeze-dried in a milk-based cryoprotective solution, as well as in a pre-denatured WPI solution. Results showed that protein gelation provided protection against acidic conditions in the stomach after 90?min, as well as against bile after 30, 60 and 90?min in the duodenum. Moreover, the milk-based cryoprotective solution was equally effective after 90?min in the duodenum. It is concluded that the gelation of whey proteins induced by Ca²⁺ ions can protect the cells against adverse conditions of the GI system. However, certain stages in the entrapment process, particularly extrusion in the solution of CaCl₂, still need to be optimized in order to reduce the mortality of the cells during gelation.     

Oil encapsulation in core–shell alginate capsules by inverse gelation. I: dripping methodology

The production of capsules by inverse gelation consists of adding dropwise oil containing calcium dispersion into an alginate bath. A dripping technique to produce capsules from oil-in-water (O/W) emulsions was proposed by Abang. However, little is known about the oil encapsulation using water-in-oil (W/O) emulsions. This work aims to develop a new method of W/O emulsions encapsulation by inverse gelation. The success of the W/O emulsion encapsulation is due to three factors: 1) use of an emulsion with moderate stability (50?min); 2) production of an emulsion with at least 90?g/L of CaCl₂ and 3) addition of ethanol (20% v/v) into the alginate bath. Both wet and dry capsules were obtained with a spherical shape with diameters of 7 and 3.6?mm, respectively. All volume of oil was encapsulated and the oil loading in the wet and dry capsules was of 23 and 68% v/v, respectively.     

Encapsulation of Lactobacillus plantarum ATCC 8014 and Pediococcus acidilactici ATCC 8042 in a freeze-dried alginate-gum arabic system and its in vitro testing under gastrointestinal conditions

Abstract

The aim of this study was to investigate the viability of Pediococcus acidilactici ATCC 8042 and Lactobacillus plantarum ATCC 8014 in a freeze-dried capsules system prepared with sodium alginate and gum arabic using the extrusion technique. The capsules made with alginate 2% (w/v)/gum arabic 2% (w/v) showed higher hardness (7.12?±?0.71?N), with highly cohesive (0.81?±?0.02) and elastic (0.99?±?0.00) features on the Texture Profile Analysis (TPA), as well as higher sphericity with 1.75?±?0.12?mm y 1.73?±?0.13?mm diameter axes and regularity in their surface by Scanning Electron Microscopy (SEM). The use of skimmed milk at 10% as a cryoprotector in the freeze-drying process allowed the obtention of high viability percentages (88% a 96%) for both strains. Best results of viability for P. acidilactici encapsulated was with the use of alginate 2% (w/v)/gum arabic 2% (w/v) (92%±2.65), and L. plantarum with the use of alginate 2% (w/v) (84.71%±10.33) during the gastrointestinal environment challenge.     

Microentrapment of probiotic bacteria in a Ca(2+)-induced whey protein gel and effects on their viability in a dynamic gastro-intestinal model

Entrapping probiotic bacteria in gels with ionic cross-linking is typically achieved with polysaccharides (alginate, pectin, carraghenan). In this study, whey proteins were used for this purpose by carrying out the Ca(2+)-induced gelation of pre-heated whey protein isolate (WPI). A Lactobacillus rhamnosus cell suspension was added in a denatured WPI solution in a 30 : 70 volume ratio. Gelation was carried out by extrusion of the cell suspension in a CaCl(2) solution. Beads of approximately 3 mm diameter were formed. The population in the beads was 8.0 x 10(8) cells g(-1). Entrapment efficiency in gel beads was 96%, with a survival level of 23%. Scanning electron microscopy of beads before freeze-drying showed a tight protein network containing encapsulated Lb. rhamnosus cells homogeneously distributed throughout the matrix. The survival to freeze-drying of the bead-entrapped cells was 41%. Viability of microentrapped cells in a dynamic gastro-intestinal (GI) model was studied and the results were compared to free cells freeze-dried in a milk-based cryoprotective solution, as well as in a pre-denatured WPI solution. Results showed that protein gelation provided protection against acidic conditions in the stomach after 90 min, as well as against bile after 30, 60 and 90 min in the duodenum. Moreover, the milk-based cryoprotective solution was equally effective after 90 min in the duodenum. It is concluded that the gelation of whey proteins induced by Ca(2+) ions can protect the cells against adverse conditions of the GI system. However, certain stages in the entrapment process, particularly extrusion in the solution of CaCl(2), still need to be optimized in order to reduce the mortality of the cells during gelation.     

Encapsulation of vitamin A

Abstract

Vitamin A was protected from degradation in the first compartment of the ruminant stomach by encapsulation by a phase-separation technique. the matrix components consisted of substituted cellulosic materials, fatty acids or a variety of proteins. Antioxidants such as butylated hydroxytoluene and ethoxyquin were incorporated in the formulations. the protective efficiency of the formulations as estimated by exposing the encapsulated vitamin A to gastric juice (microbial degradation) and to a pepsin solution (enzymatic degradation). the capsules prepared with substituted cellulosic materials gave the best protection to vitamin A from degradation.     

Beauveria brongniartii subjected to spray-drying in a composite carrier matrix system

The negative aspects of chemical pesticides are of growing concern to the public. Thus, there is a strong effort to exploit environmentally friendly possibilities for pest management. One strategy is the application of biocontrol agents such as the fungus Beauveria brongniartii. In this context, the central objective of the research presently described is to investigate spray drying as a preservation method for fungal conidia to obtain a practical formulation for spray application. An aqueous binary mixture composed of skim milk (SM) and polyvinylpyrrolidone (PVP K90) was examined as encapsulation matrix. The influence of different inlet/outlet temperature adjustments, the composition of the carrier system and the conidia concentration were examined with respect to their influence on spore viability. Results indicate that air outlet temperatures up to 53 ± 2°C resulted in a slight reduction of conidial viability (≈3%). Microencapsulated conidia have been subjected to storage tests with and without the addition of silica gel capsules at various temperatures. Results show that survival is inversely related to storage temperatures and residual moisture levels of the spray dried powders. The highest survival rates were observed at moisture contents of 3% and a temperature of 10°C. Moreover, production characteristics like entrapment efficacy, shape and size were investigated. Furthermore, the composition of the carrier matrix was optimised to result in production yields of 25%. Results show that spray drying is a useful, economic encapsulation technology for aerial conidia of Beauveria brongniartii resulting in highly concentrated, spray dried powders of 92% viability.     

Effect of process variables on particle size and viability of Bifidobacterium lactis Bb-12 in genipin-gelatin microspheres

Gelatin microspheres cross-linked with genipin were developed to encapsulate the probiotic Bifidobacterium lactis Bb-12 The effects of different gelatin concentrations (10-19% w/v), bloom strengths (175 and 300), surfactants, stirring rates during emulsion formation and genipin concentrations (0-10 mM) on the microsphere sizes and viability of bacterial cells were investigated. Principal Component Analysis revealed microsphere size distribution differed depending on the presence or absence of surfactants as well as a trend of increasing micropshere size with increasing gelatin concentration and bloom strength. Lower stirring rates resulted in larger microspheres with higher encapsulation yields of bifidobacteria Microsphere size and cell viability were not significantly (p < 0.05) influenced by increasing genipin concentrations up to 10 mM whereas microsphere stability in simulated gastric juice increased with increasing genipin concentration. The encapsulation yields were higher in 175 bloom strength gelatin microspheres than in 300. Cold-stage scanning electron microscopy showed encapsulated bacteria distributed throughout the genipin cross-linked gelatin matrix.     

Uptake and Biotransformation of 6,7-Dimethylquinoline and 6,8-Dimethylquinoline by Rainbow Trout (Salmo Gairdneri)

1. 6,7-Dimethylquinoline (6,7-DMQ) is readily taken up by rainbow trout and bioconcentrated in tissue after exposure to ca 1?mg/1 for 7.5?h. Mean bioconcentration factors (from water) were 21, 18, 6 and 14 for bile, liver, muscle and carcass respectively. Mean tissue concentrations after 69-96?h depuration were ND, ND, 0.54 and 0.48 μg/g for bile, liver, muscle and carcass respectively.

2. Major metabolites, following exposure to 6,7-DMQ, were conjugates (glucuronide or sulphate) of 7-hydroxymethyl-6-methylquinoline and 6-hydroxymethyl-7-methylquinoline. Mean concentration of metabolites in the bile were 500μg/g after 7.5?h exposure to ca 1?mg/1 and 1367 μg/g after 9.5?h exposure to ca 1?mg/1 and 69?h depuration.

3. 6,8-Dimethylquinoline (6,8-DMQ) is also readily bioconcentrated in fish tissue after exposure to ca 1?mg/1. Mean bioconcentration factors (from water) were 23, 20, 13 and 25 for bile, liver, muscle and carcass respectively. Mean tissue concentrations after 7?h exposure to ca 1?mg/1 and 63?h depuration were 4.0,0.67,0.49, and 3.2 μg/g respectively for bile, liver, muscle and carcass.

4. Major metabolites, following exposure to 6,8-DMQ were conjugates (glucuronide or sulphate) of 6,8-dimethyl-5-hydroxyquinoline, 6,8-dimethyl-7-hydroxyquinoline. 6,8-dimethyl-3-hydroxyquinoline and 6-hydroxymethyl-8-methylquinoline. Mean concentration of metabolites in the bile were 1278 μg/g after exposure to ca 1?mg/1 for 8?h and 1031 μg after exposure to ca 1?mg/1 for 7h and 63?h depuration.     

Survival of free and microencapsulated Bifidobacterium: effect of honey addition

Abstract

This study evaluated the effect of honey addition on the viability of free and emulsion encapsulated cells of two strains of Bifidobacterium that underwent simulation of human upper gastrointestinal transit. In the control condition, without honey, free cells were drastically reduced after exposure to gastrointestinal conditions. The reduction was more pronounced with Bifidobacterium J7 of human origin. On the other hand, when cells were encapsulated, the viability reduction was higher for strain Bifidobacterium Bb12. The microencapsulation improved the viability maintenance of both Bifidobacterium strains, in recommended amounts for probiotic activity, after exposure to simulated gastrointestinal conditions. Moreover, suspending free cells of both Bifidobacterium strains in honey solutions resulted in a protective effect, equivalent to the plain microencapsulation with sodium alginate 3%. It is concluded that microencapsulation and the addition of honey improved the ability of Bifidobacterium to tolerate gastrointestinal conditions in vitro.     

盐酸小檗碱与氟康唑协同抗耐药白念珠菌的动物实验

目的观察盐酸小檗碱不同剂量与氟康唑协同抗耐药白念珠菌的疗效。方法将90只ICR小鼠随机分为6组,每组15只,分别为真菌感染模型组(简称:空白对照组)、单用盐酸小檗碱(9 mg/kg)治疗组(简称小檗碱组)、氟康唑(0.5 mg/kg)单用治疗组(简称氟康唑组)、盐酸小檗碱(1 mg/kg)+氟康唑(0.5 mg/kg)治疗组(简称合用1组)、盐酸小檗碱(3 mg/kg)+氟康唑(0.5 mg/kg)治疗组(简称合用2组)、盐酸小檗碱(9 mg/kg)+氟康唑(0.5 mg/kg)治疗组(简称合用3组)。在小鼠系统性真菌感染模型建立2 h后各治疗组分别腹腔注射给药0.2 ml/10 g,1次/d,连续给药7 d,肾脏的活菌数检测换算为log10CFU/值。结果单纯小檗碱组平均存活时间3.5 d,肾脏的活菌数为log10CFU/值6.566,与空白对照组3.4 d、活菌数6.462无显著性差异(P>0.05);氟康唑组平均存活时间9.9 d、活菌数为6.566,与小檗碱组有显著性差异(P<0.05);合用1组平均存活时间12.7 d、活菌数为5.723;合用2组平均存活时间16.1 d、活菌数5.645;合用3组平均存活时间18.7 d、活菌数为4.967。两药合用组的存活时间明显延长及活菌数明显低于各单用治疗组(P<0.05或0.01),其中,合用2组和3组与氟康唑单纯治疗组相比有非常显著性差异(P<0.01)。结论盐酸小檗碱与氟康唑合用有协同抗耐药白念珠菌作用,中剂量以上小檗碱合用氟康唑能显著提高耐药白念珠菌的疗效。     

Development of chitosan–pullulan composite nanoparticles for nasal delivery of vaccines: in vivo studies

Abstract

Here, we aimed at developing chitosan/pullulan composite nanoparticles and testing their potential as novel systems for the nasal delivery of diphtheria toxoid (DT). All the chitosan derivatives [N-trimethyl (TMC), chloride and glutamate] and carboxymethyl pullulan (CMP) were synthesised and antigen-loaded composites were prepared by polyion complexation of chitosan and pullulan derivatives (particle size: 239–405?nm; surface charge: +18 and +27?mV). Their immunological effects after intranasal administration to mice were compared to intramuscular route. Composite nanoparticles induced higher levels of IgG responses than particles formed with chitosan derivative and antigen. Nasally administered TMC–pullulan composites showed higher DT serum IgG titre when compared with the other composites. Co-encapsulation of CpG ODN within TMC-CMP-DT nanoparticles resulted in a balanced Th₁/Th₂ response. TMC/pullulan composite nanoparticles also induced highest cytokine levels compared to those of chitosan salts. These findings demonstrated that TMC-CMP-DT composite nanoparticles are promising delivery system for nasal vaccination.     

脂质体包裹的反义寡核苷酸逆转耐甲氧西林金黄色葡萄球菌耐药性的研究

目的：用人工合成磷脂二棕榈酰磷脂酰胆碱（dipalmitoyl phosphatidylcholine，DPPC），二肉豆蔻酰磷脂酰甘油（dimyristoyl phosphatidylglycerol，DMPG）制备反义寡核苷酸阴离子脂质体并研究脂质体包裹的抑制耐甲氧西林金黄色葡萄球菌（methicillin resistant staphylococcus aureus，MRSA）耐药基因表达信号传导通路中BlaRlmRNA表达的反义寡核苷酸（antisense phosphothioate oligodeoxynucleotides，AS-ODNs）对MRSA耐药性的影响。方法：设计合成AS-ODNs；薄膜分散冻干法制备其脂质体；透射电镜观察脂质体的形态；离心纯化脂质体并用紫外分光光度计测定包封率、渗漏率；振荡法检测体外释放度；平板克隆形成实验计数菌落数CFU；微量法测定细菌生长曲线。结果：反义寡核苷酸阴离子脂质体大小均匀，为圆球体，包封率为77．38％，冷冻条件下保存1月后渗漏率为0．18％，体外释放度实验表明24h后约60％的药物从脂质体中释放，反义寡核苷酸脂质体可显著抑制MRSA生长，脂质体包裹的不同剂量的AS-ODNs中MRSA的菌落形成单位（CFU）与空白对照组比较明显减少，具有剂量依赖性，且效果明显优于未被脂质体包裹的AS-ODNs。结论：采用薄膜分散冻干法制备反义寡核苷酸阴离子脂质体，包封率较高，质量稳定，反义寡核苷酸脂质体能逆转MRSA的耐药性，效果明显优于单用AS-ODNs，可作为反义寡核苷酸进入细菌的载体。     

Synthesis and characterization of polyurethane–urea microcapsules containing galangal essential oil: statistical analysis of encapsulation

Galangal essential oil (GEO) is known to possess antimicrobial activity (e.g. against Staphylococcus aureus). A way to increase oil lifetime in plants is encapsulation in polyurethane–urea (PUU) microcapsules. In this study, PUU microcapsules with GEO were synthesized by interfacial polymerization at oil–water interface in oil–water emulsion. A statistical analysis of the microcapsule size was successfully applied for characterization of the encapsulation process. Using the model of reversible aggregation, it was shown that the process of encapsulation takes place in the conditions of thermodynamic control. The polymerization conditions (agitation rate in the range 2000–10?000?rpm/min) are the key factors that affect the mean microcapsule size of primary capsules formed during encapsulation. Two complementary processes were determined the mean capsule size during a transformation of these primary microcapsules: break-up and coalescence of oil droplets in the oil-in-water emulsion. The agitation rate does not influence the coalescence of the oil droplets, but the threshold value of agitation speed (in this system 4000?rpm/min) does exist and that is what strongly increases break-up of oil droplets. The higher agitation rate resulted in smaller size of microcapsules (mean diameter decreasing from 5.6 to 4.9?µm for primary capsules and from 13.8 to 9.8?µm for secondary capsules) and with a narrower size distribution. The last mode of encapsulation allows the more effective use the shell material for encapsulating of larger amount of oil.     

Preparation and in vitro evaluation of slow release ketoprofen microcapsules formulated into tablets and capsules

Abstract

Ketoprofen powder was encapsulated with Eudragit RL/RS polymer solutions in isopropanol-acetone 1:1, using a simple and rapid method. Microcapsules were prepared using Eudragit solutions with different RL/RS ratios. The encapsulation process produces free-flowing microcapsules with good drug content and marked decrease in dissolution rate. The retardation in release profile of ketoprofen from microcapsules was a function of the polymer ratio employed in the encapsulation process. In vitro release of ketoprofen from microcapsules either filled in gelatin capsules or compressed into tablets, using calcium sulphate as diluent, confirmed the efficiency of the encapsulation process for preparing prolonged release medication. A capsule formulation with optimum sustained-release profile was suggested.     

Microencapsulation of white champaca (Michelia alba D.C.) extract using octenyl succinic anhydride (OSA) starch for controlled release aroma

The objective of the study was to optimise the encapsulation of Michelia alba D.C. (MAD) extract using octenyl succinic anhydride (OSA) starch. The MAD extract (5–10?g/100?g of dry starch) and the OSA starch (25–100?g/100?ml of water) was used in microcapsule preparation and analysed for the physicochemical and encapsulation properties. The optimised formula using the MAD extract and the OSA starch were 15.00?g/100?g of dry starch and 96.32?g/100?g water, which provided the highest in yield recovery (40.65%?±?0.99) and encapsulation efficiency (68.91%?±?1.50), with the lowest moisture content (3.19%?±?0.06) and water activity (0.236?±?0.004). The aroma release from the optimum encapsulated powder in simulated artificial saliva fluid (SSF) suggested that linalool retention in microcapsules was higher than verbenone and 2-methyl butanoic acid. This study shows that the optimised formulation of MAD encapsulated flavour powder was found to be effective for controlling the aroma release.     

Enhanced Encapsulation of Amphotericin B into Liposomes by Complex Formation with Polyethylene Glycol Derivatives

Purpose. A highly efficient method was developed for the encapsulation of amphotericin B (AmB) in liposomes, and the mechanism involved was characterized. Methods. AmB was encapsulated in dipalmitoylphosphatidylcholine/cholesterol (DPPC/CH, 2:1) liposomes after complex formation with distearoyl-N-(monomethoxy poly(ethylene glycol) succinyl) phosphatidylethanolamine (DSPE-PEG). Hydration of lipids was done with 9% sucrose solution. Results. The encapsulated amount of AmB was 111 g/mg lipid, which was much higher than that obtained by the same method without DSPE-PEG (14 g/mg lipid). The amount encapsulated increased with amount of DSPE-PEG used and with PEG molecular weight. Encapsulation efficacy was also influenced by the type of PEG derivatives used and by the modification of AmB, suggesting the involvement of complex formation between AmB and DSPE-PEG. Absorption and ³¹P-NMR spectral analyses indicated that interactions between the amino and phosphate groups and between the polyene and PEG moieties in AmB and DSPE-PEG, respectively, play an important role in the complex formation. Conclusions. Complex formation of AmB with DSPE-PEG allows the highly efficient encapsulation of the drug in liposomes. This simple technique should be applicable to other hydrophobic drugs.     

Radiopaque alginate microcapsules for X-ray visualization and immunoprotection of cellular therapeutics

Alginate-poly-L-lysine-alginate (APA) microcapsules have been explored as vehicles for therapeutic drug and cell delivery. The permselectivity of these capsules provides a unique means of controlled drug release and immunoisolation of encapsulated cells. Immunoisolation is especially attractive as it abrogates the need for chronic immunosuppressive therapy and opens up the possibility for the delivery of numerous cell sources including xenogeneic grafts. APA microcapsules containing cellular therapeutics have proven effective in the short-term treatment of a wide range of diseases requiring enzyme or endocrine replacement therapy, including type I diabetes. If these microcapsules could be noninvasively monitored with X-ray imaging modalities (i.e., fluoroscopy, CT, and digital subtraction angiography), questions such as the ideal transplantation site, the best means of delivery, and the long-term survival of grafts could be better addressed. We have developed two novel alginate-based radiopaque microcapsule formulations containing either barium sulfate (Ba X-Caps) or bismuth sulfate (Bi X-Caps). As compared to conventional, nonradiopaque APA capsules, Ba X-Caps and Bi X-Caps containing human cadaveric islets resulted in a decrease in cellular viability of less than 5% up to 14 days after encapsulation. Both radiopaque capsules were found to be permeable to lectins < or =75 kDa, but were impermeable to lectins > or =120 kDa, thus ensuring the blockage of the penetration of antibodies while allowing free diffusion of insulin and nutrients. The glucose-responsive insulin secretion of the radiopaque encapsulated human islets was found to be unaltered compared to that of unlabeled controls, with human C-peptide levels ranging from 3.21 to 2.87 (Ba X-Caps) and 3.23 to 2.87 (Bi X-Caps) ng/islet at 7 and 14 days postencapsulation, respectively. Using fluoroscopy, both Ba X-Caps and Bi X-Caps could be readily visualized as single radiopaque entities in vitro. Furthermore, following transplantation in vivo in mice and rabbits, single capsules could be identified with no significant change in contrast for at least 2 weeks. This study represents the first attempt at making radiopaque microcapsules for X-ray guided delivery and imaging of cellular therapeutics. While human cadaveric islets were used as a proof-of-principle, these radiopaque capsules may have wide ranging therapeutic applications for a variety of cell types.     

Beauveria brongniartii subjected to spray-drying in a composite carrier matrix system

The negative aspects of chemical pesticides are of growing concern to the public. Thus, there is a strong effort to exploit environmentally friendly possibilities for pest management. One strategy is the application of biocontrol agents such as the fungus Beauveria brongniartii. In this context, the central objective of the research presently described is to investigate spray drying as a preservation method for fungal conidia to obtain a practical formulation for spray application. An aqueous binary mixture composed of skim milk (SM) and polyvinylpyrrolidone (PVP K90) was examined as encapsulation matrix. The influence of different inlet/outlet temperature adjustments, the composition of the carrier system and the conidia concentration were examined with respect to their influence on spore viability. Results indicate that air outlet temperatures up to 53 +/- 2 degrees C resulted in a slight reduction of conidial viability (approximately 3%). Microencapsulated conidia have been subjected to storage tests with and without the addition of silica gel capsules at various temperatures. Results show that survival is inversely related to storage temperatures and residual moisture levels of the spray dried powders. The highest survival rates were observed at moisture contents of 3% and a temperature of 10 degrees C. Moreover, production characteristics like entrapment efficacy, shape and size were investigated. Furthermore, the composition of the carrier matrix was optimised to result in production yields of 25%. Results show that spray drying is a useful, economic encapsulation technology for aerial conidia of Beauveria brongniartii resulting in highly concentrated, spray dried powders of 92% viability.