Studies of Ciprofloxacin Encapsulation on Alginate/Pectin Matrixes and Its Relationship with Biodisponibility

Preparation of Trichoderma asperellum Microcapsules and Biocontrol of Cucumber Powdery Mildew

Microencapsulation is an important technique for protecting the viability and activity of microorganisms under adverse environmental conditions. To improve biological control, controlled-release microcapsules of Trichoderma asperellum were prepared and embedded in combinations of the biodegradable wall materials sodium alginate (SA). The microcapsules were evaluated for their ability to control cucumber powdery mildew in the greenhouse. The results showed that the highest encapsulation efficiency of 95% was obtained by applying 1% SA and 4% calcium chloride. The microcapsules provided good, controlled release and UV resistance, and could be stored for a long time. The greenhouse experiment revealed that the T. asperellum microcapsules had a maximal biocontrol efficiency of 76% against cucumber powdery mildew. In summary, embedding T. asperellum in microcapsules is a promising technique to improve the survivability of T. asperellum conidia. The T. asperellum microcapsules exerted significant biocontrol efficiency against cucumber powdery mildew. IMPORTANCE Trichoderma asperellum is widely found in plant roots and soil and has been used for the biocontrol of various plant pathogens; however, the control efficiency of T. asperellum is usually unstable in field trials. To improve the control efficiency of T. asperellum, in the present study, T. asperellum microcapsules were prepared using sodium alginate as wall material to reduce the effects of temperature, UV irradiation, and other environmental factors on its activity, and to significantly improve its biocontrol efficiency on cucumber powdery mildew. Microcapsules can prolong the shelf life of microbial pesticides. This study provides a new way to prepare a biocontrol agent against cucumber powdery mildew with high efficiency.

Bacterial Cellulose-Based Materials as Dressings for Wound Healing

Bacterial cellulose (BC) is produced by several microorganisms as extracellular structures and can be modified by various physicochemical and biological strategies to produce different cellulosic formats. The main advantages of BC for biomedical applications can be summarized thus: easy moldability, purification, and scalability; high biocompatibility; and straightforward tailoring. The presence of a high amount of free hydroxyl residues, linked with water and nanoporous morphology, makes BC polymer an ideal candidate for wound healing. In this frame, acute and chronic wounds, associated with prevalent pathologies, were addressed to find adequate therapeutic strategies. Hence, the main characteristics of different BC structures-such as membranes and films, fibrous and spheroidal, nanocrystals and nanofibers, and different BC blends, as well as recent advances in BC composites with alginate, collagen, chitosan, silk sericin, and some miscellaneous blends-are reported in detail. Moreover, the development of novel antimicrobial BC and drug delivery systems are discussed.

Alginates Combined with Natural Polymers as Valuable Drug Delivery Platforms

Alginates (ALG) have been used in biomedical and pharmaceutical technologies for decades. ALG are natural polymers occurring in brown algae and feature multiple advantages, including biocompatibility, low toxicity and mucoadhesiveness. Moreover, ALG demonstrate biological activities per se, including anti-hyperlipidemic, antimicrobial, anti-reflux, immunomodulatory or anti-inflammatory activities. ALG are characterized by gelling ability, one of the most frequently utilized properties in the drug form design. ALG have numerous applications in pharmaceutical technology that include micro- and nanoparticles, tablets, mucoadhesive dosage forms, wound dressings and films. However, there are some shortcomings, which impede the development of modified-release dosage forms or formulations with adequate mechanical strength based on pure ALG. Other natural polymers combined with ALG create great potential as drug carriers, improving limitations of ALG matrices. Therefore, in this paper, ALG blends with pectins, chitosan, gelatin, and carrageenans were critically reviewed.

The New Strategy for Studying Drug-Delivery Systems with Prolonged Release: Seven-Day In Vitro Antibacterial Action

The new method of antibacterial-drug-activity investigation in vitro is proposed as a powerful strategy for understanding how carriers affect drug action during long periods (7 days). In this paper, we observed fluoroquinolone moxifloxacin (MF) antibacterial-efficiency in non-covalent complexes, with the sulfobutyl ether derivative of β-cyclodextrin (SCD) and its polymer (SCDpol). We conducted in vitro studies on two Escherichia coli strains that differed in surface morphology. It was found that MF loses its antibacterial action after 3-4 days in liquid media, whereas the inclusion of the drug in SCD led to the increase of MF antibacterial activity by up to 1.4 times within 1-5 days of the experiment. In the case of MF-SCDpol, we observed a 12-fold increase in the MF action, and a tendency to prolonged antibacterial activity. We visualized this phenomenon (the state of bacteria, cell membrane, and surface morphology) during MF and MF-carrier exposure by TEM. SCD and SCDpol did not change the drug's mechanism of action. Particle adsorption on cells was the crucial factor for determining the observed effects. The proteinaceous fimbriae on the bacteria surface gave a 2-fold increase of the drug carrier adsorption, hence the strains with fimbriae are more preferable for the proposed treatment. Furthermore, the approach to visualize the CD polymer adsorption on bacteria via TEM is suggested. We hope that the proposed comprehensive method will be useful for the studies of drug-delivery systems to uncover long-term antibacterial action.

Pectin Microspheres: Synthesis Methods, Properties, and Their Multidisciplinary Applications

There is great contemporary interest in using cleaner technologies through green chemistry and utilizing biopolymers as raw material. Pectin is found on plant cell walls, and it is commonly extracted from fruit shells, mostly apples or citrus fruits. Pectin has applications in many areas of commercial relevance; for this reason, it is possible to find available information about novel methods to transform pectin and pursuing enhanced features, with the structuring of biopolymer microspheres being highly cited to enhance its activity. The structuring of polymers is a technique that has been growing in recent decades, due to its potential for diverse applications in various fields of science and technology. Several techniques are used for the synthesis of microspheres, such as ionotropic gelation, extrusion, aerosol drying, or emulsions, with the latter being the most commonly used method based on its reproducibility and simplicity. The most cited applications are in drug delivery, especially for the treatment of colon diseases and digestive-tract-related issues. In the industrial field, it is used for protecting encapsulated compounds; moreover, the environmental applications mainly include the bioremediation of toxic substances. However, there are still many possibilities for expanding the use of this biopolymer in the environmental field.

Exploration of the Microstructure and Rheological Properties of Sodium Alginate-Pectin-Whey Protein Isolate Stabilized Β-Carotene Emulsions: To Improve Stability and Achieve Gastrointestinal Sustained Release

Sodium alginate (SA)-pectin (PEC)-whey protein isolate (WPI) complexes were used as an emulsifier to prepare β-carotene emulsions, and the encapsulation efficiency for β-carotene was up to 93.08%. The confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) images showed that the SA-PEC-WPI emulsion had a compact network structure. The SA-PEC-WPI emulsion exhibited shear-thinning behavior and was in a semi-dilute or weak network state. The SA-PEC-WPI stabilized β-carotene emulsion had better thermal, physical and chemical stability. A small amount of β-carotene (19.46 ± 1.33%) was released from SA-PEC-WPI stabilized β-carotene emulsion in simulated gastric digestion, while a large amount of β-carotene (90.33 ± 1.58%) was released in simulated intestinal digestion. Fourier transform infrared (FTIR) experiments indicated that the formation of SA-PEC-WPI stabilized β-carotene emulsion was attributed to the electrostatic and hydrogen bonding interactions between WPI and SA or PEC, and the hydrophobic interactions between β-carotene and WPI. These results can facilitate the design of polysaccharide-protein stabilized emulsions with high encapsulation efficiency and stability for nutraceutical delivery in food and supplement products.

Biopolymers for Biological Control of Plant Pathogens: Advances in Microencapsulation of Beneficial Microorganisms

The use of biofertilizers, including biocontrol agents such as Pseudomonas and Bacillus in agriculture can increase soil characteristics and plant acquisition of nutrients and enhancement the efficiency of manure and mineral fertilizer. Despite the problems that liquid and solid formulations have in maintaining the viability of microbial agents, encapsulation can improve their application with extended shelf-life, and controlled release from formulations. Research into novel formulation methods especially encapsulation techniques has increased in recent years due to the mounting demand for microbial biological control. The application of polymeric materials in agriculture has developed recently as a replacement for traditional materials and considered an improvement in technological processes in the growing of crops. This study aims to overview of types of biopolymers and methods used for encapsulation of living biological control agents, especially microbial organisms.

Effectively reducing antibiotic contamination and resistance in fishery by efficient gastrointestine-blood delivering dietary millispheres

The overuse of antibiotics during the medication treatment is inevitable in the extensively-applied intensive and semi-intensive aquaculture mode; the accompanied antibiotic contamination and antimicrobial resistance pose threats to the ecosystems and cause great loss to the aquaculture industry. To solve the problem, this work introduced the antibiotic-laden dietary millispheres (DMSs) with internal porous structure for the high availability, attractiveness and digestibility to fish. Two types of antibiotics with distinct solubilities - tetracycline chloride (TCH) and sulfadiazine (SDZ) were made into the DMSs, individually, which were then directly adopted in the feeding of fish. Carassius auratus was chosen as the target fish in this work. The mesocosm study demonstrate that, compared with the regular way of oral administration (feeding the mixture of antibiotics and commercial feed pellets), the DMSs could use much less (i.e. one order of magnitude lower) antibiotic dose to reach the equivalent antibiotic concentration in gastrointestine and blood. As a robust alternative, either TCH- or SDZ-laden DMSs achieved efficient drug delivery in vivo, which importantly facilitated the source reduction of antibiotics, the alleviation of antibiotic contamination in fishery and the control of antibiotic resistance especially in sediments.

Survival and storage stability of encapsulated probiotic under simulated digestion conditions and on dried apple snacks

The objective of the current study was to explore the probiotics carrier potential of apple dried snacks and improve the survival of probiotics under simulated gastrointestinal conditions. Purposely, the probiotics were encapsulated using two hydrogel materials (sodium alginate and carrageenan) by using encapsulator. Briefly, slices of apple were immersed in solution containing free and encapsulated probiotics and then dried by conventional drying method. The dried apple snack was analyzed for different characteristics (physiochemical and microbiological) during storage. The viability of the free and encapsulated probiotics was accessed in apple snack and under simulated gastrointestinal conditions. Apple snack rich with encapsulated probiotics showed a significant result (p < .05) regarding the survival and stability. The encapsulated probiotics decreased from 9.5 log CFU/g to 8.83 log CFU/g as compared to free probiotics that decreased to 5.28 log CFU/g. Furthermore, encapsulated probiotics exhibited a better stability under simulated gastrointestinal conditions as compared to free. During storage, an increase in phenolic content and hardness was observed while decrease in pH was noted. Results of sensory parameters indicated apple snack as potential and acceptable probiotics carrier.

Lactoferrin-Loaded Alginate Microparticles to Target Clostridioides difficile Infection

Some forms of bovine lactoferrin (bLf) are effective in delaying Clostridioides difficile growth and preventing toxin production. However, therapeutic use of bLf may be limited by protein stability issues. The objective of this study was to prepare and evaluate colon-targeted, pH-triggered alginate microparticles loaded with bioactive bLf and to evaluate their anti-C difficile defense properties in vitro. Different forms of metal-bound bLf were encapsulated in alginate microparticles using an emulsification or internal gelation method. The microparticles were coated with chitosan to control protein release. In vitro drug release studies were conducted in pH-simulated gastrointestinal conditions to investigate the release kinetics of encapsulated protein. No significant release of metal-bound bLf was observed at acidic pH; however, on reaching simulated colonic pH, most of the encapsulated lactoferrin was released. The application of bLf (5 mg/mL) delivered from alginate microparticles to human intestinal epithelial cells significantly reduced the cytotoxic effects of toxins A and B as well as bacterial supernatant on Caco-2 and Vero cells, respectively. These results are the first to suggest that alginate-bLf microparticles show protective effects against C difficile toxin-mediated epithelial damage and impairment of barrier function in human intestinal epithelial cells. The future potential of lactoferrin-loaded alginate microparticles against C difficile deserves further study.

Microencapsulation of microbial canthaxanthin with alginate and high methoxyl pectin and evaluation the release properties in neutral and acidic condition

Canthaxanthin (CX) is an orange-red keto-carotenoid with high antioxidant activity. This functional pigment is sensitive to oxygen, light, pH and heat. In this study, CX was produced by the Dietzia natronolimnaea HS-1 and was encapsulated in Alginate (Alg) and Alg-high methoxyl pectin (HMP) through O/W/O multiple emulsion/external gelation method to developed resistant microparticles among acidic and neutral pHs. Results showed that initial CX concentration had a significant influence on total CX (TCX), surface CX (SCX), microencapsulation efficiency (EE) and particles size. The highest EE% for Alg (60.21 ± 0.18) and Alg-HMP (70.60 ± 0.68) were obtained with CX initial concentration of 11 and 18 μg/mg, respectively. Alg microparticles showed smaller size compare to Alg-HMP microcapsules. Presence of CX in microparticles and good antioxidant activity was confirmed by FT-IR spectroscopy and DPPH assay, respectively. CX in vitro release was 66% and 49% in acidic condition and 76% and 50% in neutral condition for Alg and Alg-HMP, respectively. Thus, Alg-HMP-CX₁₈ microparticles were selected to be used in both neutral and acidic foods such as milk and fermented milks products as an antioxidant and a colorant agent.

Development of novel gastroretentive salbutamol sulfate-loaded sodium alginate-pectin bubble beads prepared by co-axial needle air-injection method and in vivo clinical evaluation by ultrasound studies

In the present study, the salbutamol sulfate-loaded sodium alginate-pectin (SS-loaded SA-PEC) bubble beads have been optimized and evaluated for drug loading, in vitro drug release, in vivo floating behavior in the stomach, etc. Nine batches (F1-F9) of bubble beads with different SA and PEC contents were prepared by novel co-axial needle air-injection method and related to their percent drug loading efficiency (%DLE) and percent drug release at 4 h (%R_4h) as response factors. The multivariate analysis has shown the effect of SA/PEC ratio, total polymer content, as well as their interaction on %DLE and %R_4h. In the quantitative modeling, the satisfactory adjustment of the linear models (along with interaction terms) with the experimental data for both %DLE and %R_4h has confirmed the findings of the multivariate analysis. The optimized SS-loaded SA-PEC bubble beads based on 2D (contours), 3D, desirability, and overlay plots has exhibited %DLE of 87.35 ± 2.48% (n = 3 and error = 2.94%) and %R_4h of 85.79 ± 2.98% (n = 3 and error = 0.25%). The in vitro drug release studies have shown almost complete (≥85%) SS release from all the batches within 4-6 h in simulated gastric fluid (SGF) pH 1.2. The in vivo clinical findings by ultrasound studies have shown excellent floatation (>6 h) behavior of bubble beads in the upper gastrointestinal tract (GIT) and efficient stomach-specific gastroretention.

Pectin and Pectin-Based Composite Materials: Beyond Food Texture

Pectins are plant cell wall natural heteropolysaccharides composed mainly of α-1-4 d-galacturonic acid units, which may or may not be methyl esterified, possesses neutral sugars branching that harbor functional moieties. Physicochemical features as pH, temperature, ions concentration, and cosolute presence, affect directly the extraction yield and gelling capacity of pectins. The chemical and structural features of this polysaccharide enables its interaction with a wide range of molecules, a property that scientists profit from to form new composite matrices for target/controlled delivery of therapeutic molecules, genes or cells. Considered a prebiotic dietary fiber, pectins meetmany regulations easily, regarding health applications within the pharmaceutical industry as a raw material and as an agent for the prevention of cancer. Thus, this review lists many emergent pectin-based composite materials which will probably palliate the impact of obesity, diabetes and heart disease, aid to forestall actual epidemics, expand the ken of food additives and food products design.

Hybrid bacterial cellulose–pectin films for delivery of bioactive molecules

Novel biopolymeric films based on bacterial cellulose (BC) modified with high methoxylated pectin (HMP) were developed for drug delivery.

Modified bacterial cellulose scaffolds for localized doxorubicin release in human colorectal HT-29 cells

Bacterial cellulose (BC) films modified by the in situ method with the addition of alginate (Alg) during the microbial cultivation of Gluconacetobacter hansenii under static conditions increased the loading of doxorubicin by at least three times. Biophysical analysis of BC-Alg films by scanning electron microscopy, thermogravimetry, X-ray diffraction and FTIR showed a highly homogeneous interpenetrated network scaffold without changes in the BC crystalline structure but with an increased amorphous phase. The main molecular interactions determined by FTIR between both biopolymers clearly suggest high compatibility. These results indicate that alginate plays a key role in the biophysical properties of the hybrid BC matrix. BC-Alg scaffold analysis by nitrogen adsorption isotherms revealed by the Brunauer-Emmett-Teller (BET) method an increase in surface area of about 84% and in pore volume of more than 200%. The Barrett-Joyner-Halenda (BJH) model also showed an increase of about 25% in the pore size compared to the BC film. Loading BC-Alg scaffolds with different amounts of doxorubicin decreased the cell viability of HT-29 human colorectal adenocarcinoma cell line compared to the free Dox from around 95-53% after 24h and from 63% to 37% after 48 h. Dox kinetic release from the BC-Alg nanocomposite displayed hyperbolic curves related to the different amounts of drug payload and was stable for at least 14 days. The results of the BC-Alg nanocomposites show a promissory potential for anticancer therapies of solid tumors.

Development of biopolymer nanocomposite for silver nanoparticles and Ciprofloxacin controlled release

Screening of biopolymeric gel beads containing Silver NanoParticles (Ag-NPs) stabilized in Guar Gum Alkyl Amine (GGAA) and Ciprofloxacin (Cip) was carried out in order to obtain a novel nanocomposite with controlled release profile of both antimicrobians. The selected matrix composed of Alginate/High Methoxyl Pectin (HMP)/GGAA (4:4:1) was able to co-incorporate Ag-NPs and Cip with encapsulation efficiency higher than 70%. SEM images revealed good cohesivity and compatibility between the biopolymers and the cargos. Beads provided protection against Ag-NPs degradation at acidic pHs and HMP would played a key role providing hydrophobic regions. While Cip release profile showed a pH independent diffusional process, Ag-NPs release was restricted to matrix erodability. Calcium quelating agents and/or alginate degrading enzymes could modulate the release profile. The bactericidal activity of beads was tested in liquid medium, showing cooperative effects between the antimicrobials against Pseudomonas aeruginosa, Escherichia coli, Bacillus cereus and Staphylococcus aureus. TEM images confirmed interaction of Ag-NPs with bacterial surfaces followed by membrane damage. Results suggested the nanocomposite matrix as a promising system for oral treatment of intestinal infectious diseases caused by multidrug resistant and unknown microorganisms, since both Cip and Ag-NPs would be able to reach intestine in the active form.

Effects of the sol-gel route on the structural characteristics and antibacterial activity of silica-encapsulated gentamicin

The effects of sol-gel processes, i.e., acid-catalyzed gelation, base-catalyzed gelation and base-catalyzed precipitation routes, on the encapsulation of gentamicin were investigated. The resulting xerogels were characterized using a series of complementary instrumental techniques, i.e., the adsorption/desorption of nitrogen, small-angle X-ray scattering, Fourier transform infrared spectroscopy, diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and scanning electron microscopy. The encapsulated gentamicin samples were tested against a series of Gram-positive and Gram-negative bacterial strains. The best antimicrobial activity was observed with the encapsulated gentamicin that was prepared via the precipitation route, even in comparison with the neat antibiotic, especially in the case of the Gram-positive strain Staphylococcus aureus. The gentamicin concentration on the outermost surface and the zeta potential were identified as factors that affected the highest efficiency, as observed in the case of encapsulation via the base-catalyzed process.

Tailoring of alginate-gelatin microspheres properties for oral Ciprofloxacin-controlled release against Pseudomonas aeruginosa

CONTEXT

Ciprofloxacin (Cip) is a broad spectrum antibiotic frequently used in the treatment of infectious diseases caused by Pseudomonas aeruginosa. Cip oral administration is commonly associated with poor drug biodisponibility, gastrointestinal tract irritation, and toxic undesirable side effects.

OBJECTIVE

The aim of this work is to provide an oral biopolymeric system for controlled release of Cip.

MATERIALS AND METHODS

Alginate-gelatin blend microspheres were crosslinked in the presence of 1,2-propylene glycol, calcium, and glutaraldehyde. Studies of Cip encapsulation and release were performed. Matrix characteristics were studied simultaneously by optical microscopy and Fourier transform infrared spectroscopy (FTIR) using synchrotron light, and by texturometric analysis. Microsphere surface topologies were observed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and epifluorescence microscopy.

RESULTS

Microspheres crosslinked with glutaraldehyde showed about 80% Cip encapsulation and less than 10% Cip release under simulated gastric conditions in 15 min, while a controlled release profile was observed at intestinal environment conditions. Antimicrobial activity against P. aeruginosa showed an increasing bacterial growth inhibition in time. Finally, bovine serum albumin (BSA) was used as model protein for binding of macromolecules onto active surface of microspheres, with a consequently modulation of Cip release.

DISCUSSION AND CONCLUSIONS

The results are indicating that alginate/gelatin matrix crosslinked via Ca(2+) and glutaraldehyde can be tailored by decorating the microsphere surface with biological active molecules useful for targeting, making a potential tool to improve Cip oral administration for infection diseases.

Alginate lyase and ciprofloxacin co-immobilization on biopolymeric microspheres for cystic fibrosis treatment

A new formulation is described based on biopolymeric microspheres containing alginate lyase (AL) and ciprofloxacin (Cip) for sustainable oral delivery in CF patients. Alginate (ALG) and high-methoxyl pectin (HMP) are selected as the biopolymers to develop a composite matrix. ALG microspheres coated with HMP and ALG-HMP blend are gelled in water/organic solvents mixtures, obtaining Cip encapsulations from 46.0 to 100.0%. ALG-HMP shows a Cip sustainable release profile and is able to encapsulate 90.0% of AL, showing 76.0% enzyme activity after release under simulated intestinal conditions. The developed system is a promising delivery carrier to treat chronic infection of Pseudomonas aeruginosa and to reduce the viscoelasticity of the mucus accumulated into intestine of CF patients.