Microencapsulation of a probiotic bacteria with alginate–gelatin and its properties

Lactobacillus casei ATCC 393-loaded microcapsules based on alginate and gelatin had been prepared by extrusion method and the product could increase the cell numbers of L. casei ATCC 393 to be 10⁷ CFU g^?1 in the dry state of microcapsules. The microparticles homogeneously distributed with size of 1.1 ± 0.2 mm. Four kinds of microcapsules (S₁, S₂, S₃ and S₄) exhibited swelling in simulated gastric fluid (SGF) while the beads eroded and disintegrated rapidly in simulated intestinal fluid (SIF). Cells of L. casei ATCC 393 could be continuously released from the microcapsules during simulated gastrointestinal tract (GIT) and the release amounts and speeds in SIF were much higher and faster than that in SGF. Encapsulation in alginate–gelatin microcapsules successfully improved the survival of L. casei ATCC 393 and this approach might be useful in delivery of probiotic cultures as a functional food.     

Microencapsulation of probiotics by efficient vibration technology

The target site of action of probiotics is the intestine. They must be surviving the stomach acidic condition before reaching the target site. Three probiotic bacteria were microencapsulated in sodium alginate beads using a sophisticated microencapsulation technology provided by BÜCHI B-390. This study reports the tolerance of the different microencapsulated Lactobacillus at low pH using simulated gastric juice, comparing it with the tolerance of free bacteria. The three microencapsulated strains displayed time-dependent acid sensitivity at pH values under 3.0. At pH 2.0, a dramatic reduction in bacterial survival occurred after 5?min, with only L. casei surviving after 30?min, with 75% survival. At pH 2.5 microencapsulated L. casei survived for 90?, L. reuteri survived for 60?and L. bulgaricus survived for only 30?min, respectively. The microencapsulation technology used in this study may effectively protect Lactobacillus from gastric conditions and permit comparisons between strains.     

Chemopreventive effect and lack of genotoxicity and mutagenicity of the exopolysaccharide botryosphaeran on human lymphocytes

Carbohydrate biopolymers of fungal-origin are an important natural resource in the search for new bioagents with therapeutic and nutraceutical potential. In this study the mutagenic, genotoxic, antigenotoxic and antioxidant properties of the fungal exopolysaccharide botryosphaeran, a (1 → 3)(1 → 6)-β-D-glucan, from Botryosphaeria rhodina MAMB-05, was evaluated. The mutagenicity was assessed at five concentrations in Salmonella typhimurium by the Ames test. Normal and tumor (Jurkat cells) human T lymphocyte cultures were used to evaluate the genotoxicity and antigenotoxicity (Comet assay) of botryosphaeran alone and in combination with the mutagen methyl methanesulfonate (MMS). The ability of botryosphaeran to reduce the production of reactive oxygen and nitrogen species (RONS) generated by hydrogen peroxide was assessed using the CM-H₂DCFDA probe in lymphocyte cultures under different treatment times. None of the evaluated botryosphaeran concentrations were mutagenic in bacteria, nor induced genotoxicity in normal and tumor lymphocytes. Botryosphaeran protected lymphocyte DNA against damage caused by MMS under simultaneous treatment and post-treatment conditions. However, botryosphaeran was not able to reduce the RONS generated by H₂O₂. Besides the absence of genotoxicity, botryosphaeran exerted a protective effect on human lymphocytes against genotoxic damage caused by MMS. These results are important in the validation of botryosphaeran as a therapeutic agent targeting health promotion.     

A dry powder formulation from silk fibroin microspheres as a topical auto-gelling device

With the aim of establishing the formulation of a new hydrophilic auto-gelling medical device for biomedical applications, fibroin-based microspheres were prepared. The proposed microspheres were produced by a cost-effective and industrially scalable technique, such as the spray-drying. Spray-dried silk fibroin microspheres were obtained and the effects of different hydrophilic polymer on the process yield, microsphere morphology and conformation transition of fibroin were evaluated. The final auto-gelling formulations were obtained by adding calcium gluconate (as a calcium source for alginate crosslinking) to the prepared microspheres and tested by an in vitro gelling test. This study showed that the combination of fibroin with sodium alginate and poloxamer produced the most promising auto-gelling formulation for specific biomedical applications, such as the treatment of pressure ulcers.     

Design and characterization of chitosan-alginate microspheres for ocular delivery of azelastine

Abstract

The use of mucoadhesive biopolymers is one of the best approaches to prolong the drug residence inside the cul-de-sac, consequently increasing the bioavailability. Thus, the focus of this work was to develop mucoadhesive microspheres to overcome the limitations of ocular drug delivery. The chitosan-sodium alginate microspheres of azelastine hydrochloride were fabricated using modified ionotropic gelation technique. The particle size, zeta potential, entrapment efficiency and drug release kinetics were evaluated and characterized by SEM, FT-IR, DSC, in vitro mucoadhesion and in vivo study. The microspheres had average particle size in the range of 3.55 to 6.70?µm and zeta potential +24.55 to +49.56?mV. The fabricated microspheres possess maximum drug entrapment of 73.05% with 65% mucin binding efficiency and revealed a controlled release over the 8-h period following a non-Fickian diffusion. SEM showed that microspheres were distinct solid with irregular shape. FT-IR and DSC results concluded the drug entrapment into microspheres. In vivo studies on ocular rat model revealed that azelastine microspheres had better efficacy. Chitosan sodium alginate microspheres prepared were in particle size range suitable for ocular purpose. In vitro release and in vivo efficacy studies revealed that the microspheres were effective in prolonging the drug’s presence in cul de sac with improved therapeutic efficacy.     

响应面法优化肉苁蓉松果菊苷肠溶微球的制备

目的 制备肉苁蓉松果菊苷肠溶微球,筛选最佳制备工艺,并考察其体外释放特性。方法 用离子凝胶-干燥法制备肉苁蓉松果菊苷肠溶微球,以包封率为考察指标,用响应面法优化其制备工艺。结果 制备肉苁蓉松果菊苷肠溶微球最佳工艺参数：海藻酸钠浓度36.33 mg/ml、氯化钙浓度10.82 mg/ml、壳聚糖浓度10.93 mg/ml。结论 优选的工艺稳定、可行,制备的微球包封率高、缓释效果较好。     

A Novel 4′-O-Diglycoside of Decarboxyrosmarinic Acid from Blepharis ciliaris

Abstract

A novel natural phenolic 1 was isolated from the hydroalcoholic extract of the aerial parts of Blepharis ciliaris (L.) B.L. Burtt (Acanthaceae), in addition to apigenin 7-O-glucoside 2 and apigenin-7-O-(3″-acetyl-6″-E-p-coumaroyl glucoside) 3. The structure of 1 was established as 3′,4′-dihydroxy-β-phenyl ethyl caffeate-4′-β-O-D-galactopyranosyl-(1′″→4″)-α-O-L-rhamnopyranoside [= 9′-decarboxy rosmarinic acid-4′-O-(1→4)-galactosyl rhanmoside]. Structures were determined by conventional methods of analysis, as well as by different MS and NMR techniques.     

Effect of alginate composition and purity on alginate microspheres

Background: Alginate is commonly used to microencapsulate islets in experiments with islet allografts and xenografts for the treatment of Type I diabetes. The purpose of the present study is to determine the effects of alginate composition and purity on the morphology and size of microspheres. Methods: Microcapsules produced with the impure alginate types, medium-viscosity high-guluronic acid (IMVG), low-viscosity high-G (ILVG), low-viscosity high-mannuronic acid (ILVM) and medium-viscosity high-M (IMVM) were compared with one another and others generated with a highly purified LVM (HPLVM) alginate. Droplets of 1.5% alginate from an air-syringe pump were gelled in 1.1% CaCl₂ solution. While leaving the alginate pressure and needle recess constant, the air-jacket pressure was varied between 9.5–10.5 PPSI to enhance stable microcapsule generation and different batches of microbeads were made from each alginate type. Results: The sizes of the high-guluronic acid alginate microbeads were consistently bigger than those of the corresponding high-mannuronic acid alginate beads at all air-jacket settings. At the optimal air-jacket pressure of 9.0 PPSI, the mean+SD diameter of the IMVG microbeads was 780+20?µm, while that of IMVM was 607+44?µm (p<0.0001, n?=?30). Similarly, the mean ILVG microbead diameter was 816+28 µm compared to 656+26?µm for ILVM capsules (p<0.0001, n?=?30). Less polymorphism was found with the HPLVM microspheres than with the ILVM microbeads. Conclusion: Highly purified high-mannuronic acid alginate will provide smaller, spherical microcapsules suitable for islet cell transplantation.     

Preparation and release characteristics of polymer-coated and blended alginate microspheres

To prevent a rapid drug release from alginate microspheres in simulated intestinal media, alginate microspheres were coated or blended with polymers. Three polymers were selected and evaluated such as HPMC, Eudragit RS 30D and chitosan, as both coating materials and additive polymers for controlling the drug release. This study focused on the release characteristics of polymer-coated and blended alginate microspheres, varying the type of polymer and its concentration. The alginate microspheres were prepared by dropping the mixture of drug and sodium alginate into CaCl(2) solution using a spray-gun. Polymer-coated microspheres were prepared by adding alginate microspheres into polymer solution with mild stirring. Polymer-blended microspheres were prepared by dropping the mixture of drug, sodium alginate and additive polymer with plasticizer into CaCl(2) solution. In vitro release test was carried out to investigate the release profiles in 500 ml of phosphate buffered saline (PBS, pH 7.4). As the amount of polymer in sodium alginate or coating solution increase, the drug release generally decreased. HPMC-blended microspheres swelled but withstood the disintegration, showing an ideal linear release profiles. Chitosan-coated microspheres showed smooth and round surface and extended the release of drug. In comparison with chitosan-coated microspheres, HPMC-blended alginate microspheres can be easily made and used for controlled drug delivery systems due to convenient process and controlled drug release.     

Formulation optimization and <Emphasis Type="Italic">in vivo</Emphasis> evaluation of mucoadhesive xyloglucan microspheres

Mucoadhesive microspheres of the novel polymer, xyloglucan, have been formulated and their performance characteristics have been systematically evaluated in vitro and in vivo. The mucoadhesive microspheres were obtained by incorporating glipizide as model drug in xyloglucan as a mucoadhesive polymer and sodium alginate as a gel-forming polymer by the orifice-ionic gelation method. A3² factorial design was employed to study the effect of independent variables, xyloglucan concentration (X ₁ ) and calcium chloride (CaCl₂) concentration (X ₂ ), on the dependent variables including drug entrapment efficiency, release time (t ₈₀), and percentage mucoadhesion in 1h. The best batch exhibited high drug entrapment efficiency (92.98%) and percentage mucoadhesion (78% after 1h). The drug release was also controlled for more than 8 hours. In vivo testing of the mucoadhesive microspheres revealed significant hypoglycemic effect of glipizide.     

Oral Immunization Against Candidiasis Using Lactobacillus casei Displaying Enolase 1 from Candida albicans

Candidiasis is a common fungal infection that is prevalent in immunocompromised individuals. In this study, an oral vaccine against Candida albicans was developed by using the molecular display approach. Enolase 1 protein (Eno1p) of C. albicans was expressed on the Lactobacillus casei cell surface by using poly-gamma-glutamic acid synthetase complex A from Bacillus subtilis as an anchoring protein. The Eno1p-displaying L. casei cells were used to immunize mice, which were later challenged with a lethal dose of C. albicans. The data indicated that the vaccine elicited a strong IgG response and increased the survival rate of the vaccinated mice. Furthermore, L. casei acted as a potent adjuvant and induced high antibody titers that were comparable to those induced by strong adjuvants such as the cholera toxin. Overall, the molecular display method can be used to rapidly develop vaccines that can be conveniently administered and require minimal processing.     

凝血酶-壳聚糖海藻酸钠微球止血作用研究

目的考察凝血酶 壳聚糖海藻酸钠微球止血效果。方法以壳聚糖、海藻酸钠为辅料,凝血酶为模型药物,乳化胶联法制备止血微球;建立大鼠股动脉创伤出血模型、大鼠背部渗血模型和小鼠断尾出血模型,以云南白药、创可贴、棉球止血为参比,记录止血时间,计算出血量,考察凝血酶 壳聚糖海藻酸钠微球止血效果。结果高、中、低剂量凝血酶-壳聚糖海藻酸钠微球均能明显缩短大鼠股动脉出血时间（P＜0.01）,减少出血量（P＜0.05）,止血强度随给药剂量增大而增强,无明显量效关系;高、中、低剂量凝血酶 壳聚糖海藻酸钠微球均能明显缩短小鼠断尾出血时间（P＜0.01）,高剂量组止血效果较明显,止血效果呈一定量效关系;高、中、低剂量凝血酶-壳聚糖海藻酸钠微球均能明显缩短大鼠背部渗血出血时间（P＜0.05）,降低出血量（P＜0.01）,高剂量缩短出血时间最迅速,止血效果明显,有一定的量效关系。结论凝血酶－壳聚糖海藻酸钠微球止血效果明显。     

In vivo anti-ulcerogenic effect of okra (Abelmoschus esculentus) on ethanol-induced acute gastric mucosal lesions

Context: Okra, Abelmoschus esculentus (L.) (Malvaceae), is a medicinal plant widely used in Turkish traditional medicine for the treatment of various diseases such as ulcers and gastritis.

Objective: In the present study, we evaluated the gastroprotective effect of okra against ethanol-induced acute gastric mucosal injury in animal models.

Materials and methods: Wistar rats were treated with 500, 250 or 100?mg/kg okra; 20?mg/kg famotidine (Fam); and 75?mg/kg quercetin (Que). Following a 60?min period, all the rats were given 1?mL of ethanol (80%). One hour after the administration of ethanol, all groups were sacrificed.

Results: At 5000?mg/kg, the extract produced (okra) no signs of toxicity in animals. Okra 500, 250, 100, Fam 20 and Que 75 inhibited ulcer formation by 81.0, 67.5, 67.0, 76.3 and 72.4%, respectively. Okra 500 significantly decreased edema, hemorrhage and inflammation scores compared with the ethanol group (p?p?p?p?Discussion and conclusions: Our in vivo data indicate that okra has a gastroprotective effect against ethanol and could reduce the gastric ulcer as seen from biochemical and histopathological results. We suggest that okra could be a possible therapeutic antiulcer agent.     

Spray-Dried Lactose Composite Particles Containing an Ion Complex of Alginate-Chitosan for Designing a Dry-Coated Tablet Having a Time-Controlled Releasing Function

Purpose. The properties of novel spray-dried lactose compositeparticles suitable for the coating filler of a dry-coated tablet having a longinduction period in drug release were investigated. Methods. To prepare spray-dried composite particles containingalginate-chitosan complex (SD(L/AL-CS)), an aqueous solution of lactoseand sodium alginate and the acetic acid solution of chitosan wereconcomitantly fed into the rotary atomizer of a spray-dryer. Theformation of the alginate-chitosan complex was confirmed by measuring theweight of insoluble portion in the mixture of sodium alginate andchitosan solutions. The dissolution properties of the dry-coated tabletwere measured with the JP specified paddle method. Results. The micromeritic properties of SD(L/AL-CS) were comparedto those of the SD composite particles of lactose-sodium alginate,having a good compacting property. The drug release profiles ofdry-coated tablet with SD(L/AL-CS) contained a long induction periodfollowed by a rapid drug release phase in the artificial intestinal fluid.The induction period for drug release to occur was increased with anincrease in the degree of deacetylation of chitosan and in the amountof chitosan in the formulation. The prolongation of induction periodwas attributed to the formation of an insoluble ion complex betweensodium alginate and chitosan in the composite particles, which couldform a rigid gel structure on the tablet surface. Conclusions. A time-controlled release tablet was designed with thecomposite particles of lactose containing the alginate-chitosan ioncomplex. The induction period of the dry-coated tablet could be prolongedin order to deliver the drug to the colon by controlling the type andamount of chitosan formulated in the composite particles.     

Chitosan-coated alginate microspheres for embolization and/or chemoembolization: In vivo studies

In this study, chitosan-coated alginate microspheres were prepared by the ionic complexation of alginate and chitosan biopolymers to use in embolization and/or chemoembolization studies. Biopolymeric microspheres were prepared by the ionic gelation technique of alginate with a suitable divalent cation (i.e. CaCl₂) in a suspension medium composed of mineral oil and petroleum ether including emulsifier (i.e. Tween-80) and then obtained microspheres were coated with chitosan in an aqueous chitosan solution while the medium was magnetically stirred. The obtained microspheres are in the size range of 100–400?µm and they can be prepared as required by changing the preparation conditions (i.e. stirring rate, concentration of biopolymers, molecular weight and concentration of chitosan, etc.). In the in vivo studies, New Zealand rabbits were used as the test animals. Both complete and partial embolization of the kidney were achieved by using the microspheres. The renal angiograms obtained before/after embolization and the histopathological observations showed the feasibility of the chitosan-coated alginate microspheres as an alternative embolization and/or chemoembolization agent.     

一种聚乳酸聚乙醇酸缓释微球的制备工艺

目的:研究一种制备聚乳酸聚乙醇酸(PLGA)微球的新工艺,即将海藻酸钠与钙离子螯合形成缓释凝胶的原理与复乳法制备微球的工艺相结合。方法:以牛血清白蛋白(BSA)为模型药,以包封率、载药量、产率作为评价指标,研究PLGA黏度、海藻酸钠浓度及外水相1中氯化钙浓度对微球性质的影响,并通过L9(34)正交试验设计优选微球制备的工艺条件。结果:优选的制备工艺重现性好,微球形态圆整,结构致密,平均粒径为67.5μm,载药量、包封率和产率分别为0.669%、53.38%和80.08%。结论:本研究获得了较为满意的制备PLGA微球的新工艺,微球的理化性质良好。     

Sodium alginate microspheres of metformin HCl: formulation and in vitro evaluation

Metformin microspheres with sodium alginate alone and in combination with gellan were prepared using an emulsion-cross linking method. The prepared microspheres were evaluated for their physico-chemical characteristics like particle size, morphology using SEM, incorporation efficiency, equilibrium water content (swelling) and in vitro drug release. The effect of various formulation variables like polymer concentration (sodium alginate; and proportion of gellan in microspheres prepared by a combination of sodium alginate and gellan), drug loading, crosslinking agent concentration and cross-linking time on the in vitro dissolution of the prepared microspheres were evaluated. The results showed that both the particle size and the incorporation efficiency were proportional to the polymer concentration. In case of microspheres containing both sodium alginate and gellan, the mean diameter and the incorporation efficiency were higher than the corresponding microspheres containing only alginate, both increasing with an increase in proportion of gellan. The prepared microspheres were found to be discrete and spherical in shape and were successful in sustaining the drug release for 8 hours. Incorporation of gellan caused a significant decrease in drug release. The release followed a biphasic profile, in all cases, characterized by an initial phase of moderate drug release followed by a phase of higher release. Further, the kinetic treatment of the dissolution data revealed the prevalence of matrix diffusion kinetics.     

Note: Xanthone glycosides from Swertia franchetiana

A new xanthone glycoside (1) has been isolated from Swertia franchetiana together with five known xanthone glycosides. Their structures were elucidated as 7-O-[β-d-xylopyranosyl-(1→2)-β-d-xylopyranosyl]-1,7,8-trihydroxy-3-methoxyxanthone (1), 7-O-[α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyl]-1,7,8-trihydroxy-3-methoxyxanthone (2), 8-O-β-d-glucopyranosyl-1,3,5,8-tetrahydroxyxanthone (3), 1-O-β-d-glucopyranosyl-1-hydroxy-3,7,8-trimethoxyxanthone (4), 1-O-[β-d-xylopyranosyl-(1→6)-β-d-glucopyranosyl]-1-hydroxy-2,3,5-trimethoxyxanthone (5) and 1-O-[β-d-xylopyranosyl-(1→6)-β-d-glucopyranosyl]-1-hydroxy-3,5-dimethoxyxanthone (6) on the basis of spectroscopic evidence.     

正辛胺改性海藻酸钠凝胶微球的制备及其性质研究

目的:制备正辛胺改性海藻酸钠凝胶微球,并研究其性质。方法:以超声波辅助氧化法制备多醛基海藻酸钠,通过希夫碱反应制备正辛胺改性海藻酸钠,并表征其结构;以乳化-内部凝胶化技术制备负载小分子抗肿瘤药物β-榄香烯的改性海藻酸钠凝胶微球,采用气相色谱法测定其8、15、24、48h时的累积释放率及海藻酸钠和正辛胺改性海藻酸钠凝胶微球中β-榄香烯的包封率。结果:表征并证实了多醛基海藻酸钠和正辛胺改性海藻酸钠的结构;制备得到的改性海藻酸钠凝胶微球中8、15、24、48h时β-榄香烯的累积释放率分别为16%、28%、40%、83%;海藻酸钠和正辛胺改性海藻酸钠凝胶微球中β-榄香烯的包封率分别为36%、73%。结论:制备的正辛胺改性海藻酸钠凝胶微球,具有优良的缓释性能,对β-榄香烯的包封率高。     

Insulin encapsulation in reinforced alginate microspheres prepared by internal gelation.

Insulin-loaded alginate microspheres prepared by emulsification/internal gelation were reinforced by blending with polyanionic additive polymers and/or chitosan-coating in order to increase the protection of insulin at simulated gastric pH and obtain a sustained release at simulated intestinal pH. Polyanionic additive polymers blended with alginate were cellulose acetate phtalate (CAP), Eudragit L100 (EL100), sodium carboxymethylcellulose (CMC), polyphosphate (PP), dextran sulfate (DS) and cellulose sulfate (CS). Chitosan-coating was applied by using a one-stage procedure. The influence of additive polymers and chitosan-coating on the size distribution of microspheres, encapsulation efficiency and release profile of insulin in simulated gastrointestinal pH conditions was studied. The mean diameter of blended microspheres ranged from 65 to 106 microm and encapsulation efficiency of insulin varied from 14 to 100%, reaching a maximum value when CS and DS were incorporated in the alginate matrix. Insulin release, at pH 1.2, was almost prevented by the incorporation of PP, DS and CS. When uncoated microspheres were transferred to pH 6.8, a fast dissolution occurred, independently of the additive polymer blended with alginate, and insulin was completely released. Increasing the additive polymer concentration in the alginate matrix and/or chitosan-coating the blended alginate microspheres did not promote a sustained release of insulin from microspheres at pH 6.8.