Immobilization of Lactobacillus bulgaricus with gellan gum and its application in continuous fermentation of D-lactic acid from corn straw / 生物工程学报

Biorefinery of chemicals from straw is an effective approach to alleviate the environmental pollution caused by straw burning. In this paper, we prepared gellan gum immobilized Lactobacillus bulgaricus T15 gel beads (LA-GAGR-T15 gel beads), characterized their properties, and established a continuous cell recycle fermentation process for D-lactate (D-LA) production using the LA-GAGR-T15 gel beads. The fracture stress of LA-GAGR-T15 gel beads was (91.68±0.11) kPa, which was 125.12% higher than that of the calcium alginate immobilized T15 gel beads (calcium alginate-T15 gel beads). This indicated that the strength of LA-GAGR-T15 gel beads was stronger, and the strain was less likely to leak out. The average D-LA production was (72.90±2.79) g/L after fermentation for ten recycles (720 h) using LA-GAGR-T15 gel beads as the starting strain and glucose as the substrate, which was 33.85% higher than that of calcium alginate-T15 gel beads and 37.70% higher than that of free T15. Subsequently, glucose was replaced by enzymatically hydrolyzed corn straw and fermented for ten recycles (240 h) using LA-GAGR-T15 gel beads. The yield of D-LA reached (1.74±0.79) g/(L·h), which was much higher than that of using free bacteria. The wear rate of gel beads was less than 5% after ten recycles, which indicated that LA-GAGR is a good carrier for cell immobilization and can be widely used in industrial fermentation. This study provides basic data for the industrial production of D-LA using cell-recycled fermentation, and provides a new way for the biorefinery of D-LA from corn straw.

Novas estratégias terapêuticas para o controle de biofilmes orais: terapia fotodinâmica e sistema carreador de antimicrobianos / New therapeutic strategics for the control of oral biofilms: photodynamic therapy and drug delivery system

Os biofilmes orais possuem grande relevância clínica por estarem associados com o desenvolvimento de cárie dentária e candidose bucal, que são doenças infecciosas frequentemente encontradas na população. O presente trabalho foi dividido em dois estudos: Estudo 1 que teve como objetivo analisar os efeitos da terapia fotodinâmica antimicrobiana (TFDa), mediada por Fotoenticine (FTC) e Azul de Metileno (AM), sobre biofilmes microcosmos de cárie dentária; e Estudo 2 cujo objetivo foi avaliar o gellan gum como biomaterial para carreador do antifúngico Ester fenetil do ácido caféico (CAPE) contra Candida albicans. No estudo 1, amostras de dentina cariada foram coletadas de diferentes pacientes para formar biofilmes microcosmos in vitro. Os biofilmes foram tratados com FTC ou AM associado à irradiação LED a 660 nm (28,5 J/cm²). Os dados foram analisados pela contagem de Unidades Formadoras de Colônias (UFC/mL). Além disso, a biomassa, estrutura do biofilme e produção de ácidos pelos microrganismos foram determinadas por análises microscópicas ou espectrofotométricas. Os biofilmes de diferentes pacientes apresentaram variações na composição microbiana, sendo formados por estreptococos, lactobacilos e leveduras. No geral, a TFDa diminuiu 3,7 Log10 do total de microrganismos, 2,8 Log10 de estreptococos, 3,2 Log10 de lactobacilos e 3,2 Log10 de leveduras, e atingiu a erradicação de estreptococos do grupo mutans. A TFDa também foi capaz de reduzir a biomassa, desagregar os biofilmes e diminuir a concentração de ácidos em 1,1 a 1,9 mmol de lactato/L. Em relação ao estudo 2, inicialmente, foram preparadas formulações do CAPE em diferentes concentrações de gellan gum (0,6 a 1%). As formulações foram avaliadas em relação ao sistema de liberação e ação antifúngica contra C. albicans. Verificou-se que concentrações mais altas de gellan (0,9 e 1%) levaram a uma liberação mais prolongada do CAPE em relação as concentrações mais baixas. Os valores de concentração inibitória mínima do CAPE sobre C. albicans foram aumentados quando esse composto foi incorporado no gellan. As formulações de CAPE em gellan apresentaram atividade antifúngica tanto em culturas planctônicas como em biofilmes de C. albicans, sendo esses efeitos dependentes do tempo de tratamento. O CAPE e suas formulações em gellan também levaram a uma diminuição da atividade proteolítica de C. albicans. Concluiu-se que a TFDa mediada por Fotoenticine e o sistema carreador de gellan gum podem ser estratégias terapêuticas promissoras para o controle dos biofilmes na cavidade bucal, podendo ser usadas respectivamente no tratamento da cárie e candidose. (AU)

Dental caries and oral candidiasis are infectious diseases frequently found in the population. The present work is divided into two studies, study 1 time as objective: To analyze the effects of antimicrobial photodynamic therapy (aPDT), mediated by Fotoenticine (FTC) and Methylene Blue (MB), on dental caries microcosm biofilms. In study 2, the objective was to evaluate gellan gum as a biomaterial to carry the antifungal caffeic acid phenethyl ester (CAPE) on Candida albicans. To conduct study 1, carious dentin samples were collected from different patients to form in vitro microcosm biofilms. The biofilms were treated with FTC or MB associated with 660 nm red LED irradiation, with energy dose of 28.5 J/cm² and power dose of 40 mW/cm². The data were analyzed by the count of Colony Forming Units (CFU/mL). In addition, the biomass, biofilm structure and acid production of the microorganisms were determined by microscopic or spectrophotometric analysis. The biofilms from different patients showed variations in microbial composition, being formed by streptococci, lactobacilli, and yeasts. Overall, aPDT decreased 3.7 Log10 of total microorganisms, 2.8 Log10 of streptococci, 3.2 Log10 of lactobacilli and 3.2 Log10 of yeasts, and achieved eradication of mutans group streptococci. PDTa was also able to reduce biomass, disaggregate biofilms, and decrease acid concentration by 1.1 to 1.9 mmol lactate/L. For study 2 of this, first the standards of CAPE were determined, such as minimum inhibitory concentration, and absorption peak, then CAPE was incorporated into gellan gum, and then the standard curve test and analysis of CAPE release was performed, finally the formulations were tested on planktonic culture and biofilm of different strains of C. albicans, it was also analyzed the action of this drug on the production of Sap. The MIC found varied from 32 to 64 µg/mL, the release tests showed a gradual release in the higher formulations, finally in the CFU/mL count both in planktonic culture and biofilm the formulations were able to inhibit the fungus. With this it is concluded that both aPDT for oral microcosm and gellan gum as caregiver of CAPE for Candida albicans inhibition are promising. (AU)

Development of novel mucoadhesive gels containing nanoparticle for buccal administration of dexamethasone

Abstract This study aimed to develop promising and innovative mucoadhesive gel systems containing dexamethasone-loaded nanoparticle to increase the effectiveness of treatment for oral precancerous lesions and to reduce side effects. In this respect, a dexamethasone-loaded nanoparticle formulation was prepared by using emulsification/solvent evaporation method. The nanoparticle has high zeta potential (-10.3±0.5 mV), low particle size (218.42±2.1), low polydispersity index (0.070±0.014) and high encapsulation efficiency (95.018±2.982%). To improve the mucosal retention time, the dexamethasone-loaded nanoparticle was dispersed in mucoadhesive gel using gellan gum. The developed gels offered appropriate pH value, high drug content, suitable mechanical and mucoadhesive performance and appropriate viscosity for mucosal administration. All formulations exhibited plastic flow and typical gel-type mechanical spectra after the determined frequency value. The developed formulations exhibited extended drug release as intended for these systems. Cytotoxicity was tested by MTT assay in human epithelioid carcinoma cell (HeLa) in vitro. The MTT assay showed that the blank formulations were non-toxic to cells. It was observed that the bioactivity of the free dexamethasone was potentiated by mucoadhesive gels containing dexamethasone-loaded nanoparticle in HeLa cells. Results from this study indicate that mucoadhesive gels are effective for the local treatment of precancerous lesions. Our findings showed that the developed formulations were worthy of further studies.

Formulation And Evaluation Of Solid Dispersion Incorporated Fast Disintegrating Tablets Of Tenoxicam Using Design Of Experiment

The aim of the present work is to develop fast dissolving tablets from the solid dispersion of Tenoxicam for enhancement of solubility. The solid dispersions of Tenoxicam were prepared with Kollidon CL, PVP K30 and Poloxamer 127, in 1:1:1, 1:2:1 and 1:3:1 by using solvent evaporation method. The prepared solid dispersions were analyzed for all the physical parameters, drug: carrier interactions like FTIR, SEM, XRD. Solid dispersions showed a better dissolution compared to the pure drugs and among all the other formulations SD9 shows high percentage drug release i.e. 99.11 ± 5.17% for 90 min and selected as an optimized formulation for the preparation of fast disintegrating tablets of Tenoxicam. Gellan Gum, Fenugreek Seed Mucilage and L-HPC (low, middle and high concentrations) used in the preparation of fast disintegrating tablets prepared by direct compression method using 33 Response surface method. The post compression parameters of all the prepared tablets were within the limits. TF13 was selected as optimized formulation based on its highest disintegration time 36 sec and drug release 99.68 ± 1.52% for 10 min. Drug-excipients characterization also revealed that there is no interaction. Hence it concluded that solid dispersions incorporated fast disintegrating tablets is very useful approach for immediate release of Tenoxicam in the efficient management of inflammation and pain.

INCREMENTO EN LA VIDA ÚTIL POST COSECHA DEL AGUACATE (Persea americana) UTILIZANDO RECUBRIMIENTOS A BASE DE GOMA GELANA

El aguacate es uno de los frutos de importancia económica en Colombia que presenta pérdidas en post cosecha. El objetivo de esta investigación fue evaluar el efecto de un recubrimiento comestible a base de gelana de alto (GAA) y bajo acilo (GBA), sobre la calidad post cosecha del aguacate (Persea americana cv. "Hass"), almacenado durante nueve semanas. Para la elaboración de los recubrimientos, se utilizó un diseño factorial 2³, donde los factores fueron las concentraciones de GAA (0,30 y 0,60% p/v), GBA (0,30 y 0,60% p/v) y glicerol (GLI) (8,0 y 12% v/v); como agente antimicrobiano, se utilizó extracto acuoso de Toronjil (Melissa officinalis L), por ser un aditivo natural. Se evaluaron propiedades, como la firmeza, la pérdida de humedad, el pH y los sólidos solubles totales (SST), durante almacenamiento. Finalmente, para la estimación del periodo de vida útil, se empleó la ecuación de Monod Hinshelwood, previo modelado de los datos, con ayuda de la ecuación de Baranyi y Roberts. Los resultados indicaron que la aplicación de recubrimientos comestibles de goma gelana, conteniendo bajas concentraciones de glicerol, disminuye significativamente (P<0,05) la pérdida de firmeza, de humedad, de sólidos solubles y evitan grandes modificaciones del pH, manteniendo la calidad del aguacate, alargando la vida útil.

Avocado is one of the fruits of economic importance in Colombia. However, it presents losses mainly during the post-harvest period. The aim of this research was to evaluate the effect of an edible coating based on high acyl (HAG) and low acyl gellan (LAG) on post-harvest avocado quality (Persea americana cv. "Hass") stored during nine weeks. A factorial design 2³ was employed for the biofilm preparation, where the factors were concentrations of HAG (0.30 and 0.60% w/v), LAG (0.30 and 0.60% w/v) and glycerol (GLY v/v). As antimicrobial aqueous extract of lemon balm (Melissa officinalis L) was used. Properties such as firmness, moisture loss, pH, total soluble solids (TSS) during storage were evaluated. Finally, for the microbiological shelf life estimation the Hinshelwood Monod equation was applied previous data modeling using the Baranyi and Roberts model. The results indicated that the application of edible coatings based on gellan gum containing low concentrations of glycerol reduces the loss of firmness, moisture, soluble solids and prevent large changes in pH, maintaining the quality of avocado and extend its shelf life.

Desenvolvimento e caracterização de filmes e comprimidos bucais a base de pectina e goma gelana para liberação tópica de triancinolona / Development and characterization of films and buccal tablets based on pectin and gellan gum for the topical release of triamcinolone

O tratamento farmacológico de patologias bucais é conduzido, geralmente, por via de adminis-tração local. No entanto, devido ao pouco tempo de permanência do fármaco no local de ação, esse tratamento pode ser bastante comprometido. Assim, este trabalho teve por objetivo o de-senvolvimento de formas farmacêuticas que proporcionem a liberação local de triancinolona na cavidade oral. Foram produzidos filmes e comprimidos mucoadesivos a partir de polímeros naturais como gelana e pectina. Os filmes bucais foram preparados por meio de evaporação do solvente (solvent casting) utilizando diferentes quantidades de polímeros. As matérias-primas e os filmes foram caracterizados fisico quimicamente utilizando espectroscopia vibracional (in-fravermelho com transformada de Fourier e Raman) e difração de raios X. As propiedades físicas e mecânicas dos filmes também foram avaliadas. Além disso, realizou-se os ensaios de mucoadesividade e de dissolução do fármaco. Os comprimidos foram preparados por com-pressão direta usando como base os polímeros naturais. Diferentes parâmetros em relação as misturas e as formulações foram avaliados tais como as propriedades de fluxo dos pós consti-tuintes, peso médio, dureza, friabilidade e desintegração. Em relação aos filmes bucais, estes foram obtidos com sucesso através de um método simples, sem a utilização de agentes reticu-lantes, ácidos ou solventes orgânicos. Todos apresentaram bons resultados nas propriedades avaliadas, no entanto as formulações com quantidades intermediarias de polímeros foram as melhores. Dentre as formulações de comprimidos preparadas, apenas 4 apresentaram boas ca-racterísticas, no entanto, os resultados dos ensaios de dissolução mostraram que estas formula-ções têm capacidade de agir como sistema de liberação controlada de fármacos.

Pharmacological treatment of oral pathologies is usually conducted by local administration. However, due to the short time the drug stays in the site of action, this treatment can be quite compromised. Thus, the objective of this work was to develop pharmaceutical forms that pro-vide the local release of triamcinolone in the oral cavity. Mucoadhesive films and tablets were made from natural polymers such as gellan and pectin. The buccal films were prepared by sol-vent casting using different amounts of polymers. The raw materials and films were characte-rized physically chemically using vibrational spectroscopy (FTIR and Raman) and X-ray diffraction. The physical and mechanical properties of the films were also evaluated. In addi-tion, the mucoadhesive and drug dissolution tests were performed. The tablets were prepared by direct pressing with the natural polymers. Different parameters in relation to mixtures and formulations were evaluated such as the flow properties of the constituent powders, average weight, hardness, friability and disintegration. In relation to oral films, these were successfully obtained by a simple method, without the use of crosslinking agents, acids or organic solvents. All presented good results in the evaluated properties, however the formulations with interme-diate amounts of polymers were the best. Among the tablet formulations prepared, only 4 sho-wed good characteristics, however, the dissolution test results showed that these formulations have the ability to act as a controlled drug delivery system.

Desenvolvimento e caracterização de filmes e comprimidos bucais a base de pectina e goma gelana para liberação tópica de triancinolona / Development and characterization of films and buccal tablets based on pectin and gellan gum for the topical release of triamcinolone

O tratamento farmacológico de patologias bucais é conduzido, geralmente, por via de administração local. No entanto, devido ao pouco tempo de permanência do fármaco no local de ação, esse tratamento pode ser bastante comprometido. Assim, este trabalho teve por objetivo o desenvolvimento de formas farmacêuticas que proporcionem a liberação local de triancinolona na cavidade oral. Foram produzidos filmes e comprimidos mucoadesivos a partir de polímeros naturais como gelana e pectina. Os filmes bucais foram preparados por meio de evaporação do solvente (solvent casting) utilizando diferentes quantidades de polímeros. As matérias-primas e os filmes foram caracterizados fisico quimicamente utilizando espectroscopia vibracional (in-infravermelho com transformada de Fourier e Raman) e difração de raios X. As propriedades físicas e mecânicas dos filmes também foram avaliadas. Além disso, realizou-se os ensaios de mucoadesividade e de dissolução do fármaco. Os comprimidos foram preparados por com-pressão direta usando como base os polímeros naturais. Diferentes parâmetros em relação as misturas e as formulações foram avaliados tais como as propriedades de fluxo dos pós constituintes, peso médio, dureza, friabilidade e desintegração. Em relação aos filmes bucais, estes foram obtidos com sucesso através de um método simples, sem a utilização de agentes reticulantes, ácidos ou solventes orgânicos. Todos apresentaram bons resultados nas propriedades avaliadas, no entanto as formulações com quantidades intermediarias de polímeros foram as melhores. Dentre as formulações de comprimidos preparadas, apenas 4 apresentaram boas características, no entanto, os resultados dos ensaios de dissolução mostraram que estas formulações têm capacidade de agir como sistema de liberação controlada de fármacos

Pharmacological treatment of oral pathologies is usually conducted by local administration. However, due to the short time the drug stays in the site of action, this treatment can be quite compromised. Thus, the objective of this work was to develop pharmaceutical forms that pro-vide the local release of triamcinolone in the oral cavity. Mucoadhesive films and tablets were made from natural polymers such as gellan and pectin. The buccal films were prepared by sol-vent casting using different amounts of polymers. The raw materials and films were characte-rized physically chemically using vibrational spectroscopy (FTIR and Raman) and X-ray diffraction. The physical and mechanical properties of the films were also evaluated. In addi-tion, the mucoadhesive and drug dissolution tests were performed. The tablets were prepared by direct pressing with the natural polymers. Different parameters in relation to mixtures and formulations were evaluated such as the flow properties of the constituent powders, average weight, hardness, friability and disintegration. In relation to oral films, these were successfully obtained by a simple method, without the use of crosslinking agents, acids or organic solvents. All presented good results in the evaluated properties, however the formulations with interme-diate amounts of polymers were the best. Among the tablet formulations prepared, only 4 sho-wed good characteristics, however, the dissolution test results showed that these formulations have the ability to act as a controlled drug delivery system

A Novel In Situ Gel Formulation of Ranitidine for Oral Sustained Delivery

The main purpose of this study was to develop a novel, in situ gel system for sustained delivery of ranitidine hydrochloride. Ranitidine in situ gels at 0.2%, 0.5%, and 1.0% gellan gum concentration (w/v) were prepared, respectively, and characterized in terms of preparation, viscosity and in vitro release. The viscosity of the gellan gum formulations in solution increased with increasing concentrations of gellan gum. In vitro study showed that the release of ranitidine from these gels was characterized by an initial phase of high release (burst effect) and translated to the second phase of moderate release. Single photon emission computing tomography technique was used to evaluate the stomach residence time of gel containing 99mTc tracer. The animal experiment suggested in situ gel had feasibility of forming gels in stomach and sustained the ranitidine release from the gels over the period of at least 8 h. In conclusion, the in situ gel system is a promising approach for the oral delivery of ranitidine for the therapeutic effects improvement.