Processamento e conservação de enxertos de pele: uma abordagem com foco nos métodos de criopreservação, liofilização e glicerolização / Skin grafts processing and conservation: an approach focusing on cryopreservation, freeze-drying and glycerol conservation methods

Introdução: o uso de substitutos cutâneos para o tratamento de diversas feridas graves é uma forma eficiente de prevenir infecções e favorecer o processo de reepitelização. No entanto, tecidos biológicos estão suscetíveis a degradação e contaminação. Por isso, devem ser submetidos a rigorosos protocolos de processamento e testes que comprovem suas contribuições benéficas e segurança de aplicação. Objetivo: trazer uma abordagem sobre as principais características dos métodos de criopreservação, glicerolização e liofilização e sua consequencia nos aspectos imunológicos, microbiológicos e de viabilidade tecidual de enxertos de pele humana. Metodologia: foi realizada uma busca online utilizando as palavras chaves "criopreservação", "liofilização", "glicerolização", "enxertos", "processamento tecidual" e "engenharia dos tecidos" em múltiplas combinações nos bancos de dados PubMed, LILACS e ScienceDirect. Resultados: 200 artigos científicos foram obtidos, 26 excluídos por duplicidade, 92 selecionados para leitura integral a partir da leitura de seus resumos e 27 utilizados na construção desta revisão. A liofilização e a glicerolização são métodos semelhantes considerando a viabilidade tecidual. O uso de glicerol traz como principal desvantagem sua citotoxicidade quando comparado aos outros métodos. A criopreservação mantém os tecidos viáveis. Contudo, pode ser mais cara e trazer riscos de transmissão de microorganismos patogênicos. De modo geral, não é bem estabelecido quais os melhores métodos de conservação para uma adequada conservação da viabilidade dos enxertos de pele. Considerações Finais: os 3 métodos, liofilização, glicerolização e criopreservação, possuem aplicabilidade na conservação de enxertos. A falta de padronização na aplicação de enxertos apesar de sua frequente aplicação e a escassez de estudos recentes sobre o tema justificam o presente estudo.

Introduction: the use of skin substitutes for treatment of several wounds is an efficient way to prevent infections and allow the re-epithelialization process. However, biological tissues are susceptible to degradation and contamination. Therefore, they must undergo rigorous processing and testing protocols that prove their beneficial contributions and application security. Objective:to bring an approach on the main characteristics of cryopreservation, freeze-drying and glycerol conservation methods and their implications on immunological, microbiological and tissue viability aspects when applied to human skin grafts. Methodology:a mostly online search was performed using the keywords "cryopreservation", "freeze-drying", "glycerol conservation", "grafts", "tissue processing" and "tissue engineering" in multiple combinations in PubMed, LILACS and ScienceDirect databases. Results: 200 scientific articles were rescued, 26 excluded by duplicity, 92 selected for full reading from the reading of their abstracts and 27 used in the construction of this review. Freeze-drying and glycerol conservation are similar methods, with glycerol conservation having greater economic advantage. The use of glycerol presents cytotoxicity when compared to the other methods. Cryopreservation keeps tissues viable, however, is more expensive and carry risks of transmission of pathogenic microorganisms. Overall, there is a lack of clarity about the importance of viability in the performance of skin grafts. Final considerations: the 3 methods have applicability in graft conservation. The lack of standardization in graft application despite its frequent application and the scarcity of recent studies on the subject justify the present study.

Effect of the drying method and texture improvers on reconstitution behavior of yogurt powder: physical and microbiological properties / Efecto del método de secado y mejoradores de textura sobre el comportamiento de reconstitución de un yogurt en polvo: propiedades físicas y microbiológicas

Background: One of the most used and effective preservation strategies in foods is drying. However, there are problems with the rheological properties, color, and viability of lactic acid bacteria in the yogurt once reconstituted when applying such conservation strategies. Objectives: Determine the concentration of the type of texture improver and drying that minimizes the negative effect on the rheological, color, and microbiological properties of a reconstituted yogurt powder. Methods: Intended to determine the texture improver which increases rheological properties of reconstituted yogurt powder, a mixture type experimental design was applied where three texture improvers were assessed; carboxymethylcellulose (CMC) (mass fraction 0 - 1), pectin (mass fraction 0 - 1), and xanthan gum (mass fraction 0 - 1). The rheological parameters; consistency index (K), flow behavior (n), viscosity at 100s-1 (η), the storage (G') and loss (G'') modules, and the phase shift angle (δ) of each of the reconstitutions were considered as design-dependent variables. Secondly, a central composite design (face-centered) was used for assessing the effectiveness of the drying (convection, spray-drying, and freeze-drying), the concentration of the texture improver (0.0 - 1.0 %), and the yogurt powder concentration (8.0 - 15.0 %). The above-mentioned rheological parameters, color, and viability of the lactic acid bacteria from each reconstituted yogurt powder were considered as the dependent variables. Optimization sought to match the parameters of reconstituted yogurt powder that approximated the conditions of fresh yogurt. Results: The independent variables in their lineal expression and some interactions between them had statistically significant differences (p < 0.05). At a concentration of 10.59 % with 0.03 % xanthan gum, the reconstitution of freeze-dried yogurt powder was the optimized condition (p < 0.05) and obtained the rheological, color, and microbiological parameters closest to fresh yogurt. Conclusions: The drying of the yogurt by freeze-drying mixed with xanthan gum as a texture improver allowed to obtain a reconstituted yogurt with properties close to the fresh product for direct consumption

Antecedentes: Una de las estrategias de conservación más utilizadas y efectivas en los alimentos es el secado. Sin embargo, existen problemas en las propiedades reológicas, el color y la viabilidad de bacterias ácido lácticas en el yogur una vez reconstituido al aplicar tales estrategias de conservación. Objetivos: Determinar la concentración del tipo de mejorador de textura y secado que minimiza el efecto negativo sobre las propiedades reológicas, de color y microbiológicas de un yogur en polvo reconstituido. Métodos: Para determinar el mejorador de textura que aumente las propiedades reológicas del yogur en polvo reconstituido, se aplicó un diseño experimental de tipo de mezcla donde se evaluaron tres mejoradores de textura; carboximetilcelulosa (CMC) (fracción de masa 0 -1), pectina (fracción de masa 0 -1) y goma xantan (fracción de masa 0 -1); los parámetros reológicos: índice de consistencia (K), comportamiento de flujo (n), viscosidad a 100s-1 (η), módulos de almacenamiento (G') y pérdida (G''), y ángulo de desfase (δ) de cada una de las reconstituciones fueron considerados como variables dependientes. En segundo lugar, se utilizó un diseño central compuesto (centrado a las caras) para evaluar el efecto del tipo de secado (convección, secado por aspersión y liofilización), la concentración del mejorador de textura (0.0 - 1.0 %) y concentración del yogur en polvo (8.0 - 15.0 %). Como variables dependientes se consideraron los parámetros reológicos mencionados anteriormente, el color y la viabilidad de las bacterias ácido lácticas de cada yogur en polvo reconstituido. La optimización buscó igualar los parámetros del yogur en polvo reconstituido que se aproximaran a las condiciones del yogur fresco. Resultados: Las variables independientes en su expresión lineal y algunas interacciones entre ellas tuvieron diferencias estadísticamente significativas (p < 0.05). La reconstitución de yogur liofilizado en polvo a una concentración de 10.59 % con 0.03 % de goma xantan, fueron las condiciones optimizadas (p < 0.05) que obtuvieron los parámetros reológicos, de color y microbiológicos más cercanos al yogur fresco. Conclusión: El secado del yogur por liofilización mezclado con goma xantan como mejorador de la textura, permitió obtener un yogur reconstituido con propiedades cercanas al producto fresco para consumo directo

Development of a new protocol for freeze-drying preservation of Pseudoalteromonas nigrifaciens and its protective effect on other marine bacteria

Background: Freeze-drying is known as one of the best methods to preserve bacterial strains. Protectant is the key factor affecting the survival rate of freeze-dried strains. In addition, salinity, bacterial suspension concentration, drying time, and other factors can also affect the survival rate of strains to varying degrees. At present, there are relatively few studies on freeze-drying preservation of marine bacteria. In the present study, we performed the freeze-drying protectant screening and optimized the preservation conditions for Pseudoalteromonas nigrifaciens, which is widely distributed in marine environment. The protective effects of the screened protectants were verified by 18 other marine bacterial strains. Results: The results indicated that the combination of 5.0% (w/v) lactose, 5.0% (w/v) mannitol, 5.0% (w/v) trehalose, 10.0% (w/v) skim milk powder, 0.5% (w/v) ascorbic acid and 0.5% (w/v) gelatin was the best choice for the preservation of P. nigrifaciens. The suggested salinity and concentration of initial cell suspension were 10 g/L NaCl and 1.0 × 109 CFU/mL, respectively. Furthermore, stationary-phase cells were the best choice for the freeze-drying process. The highest survival rate of P. nigrifaciens reached 52.8% when using 5­10% (w/v) skim milk as rehydration medium. Moreover, the other 18 marine strains belonging to Pseudoalteromonas, Vibrio, Photobacterium, Planomicrobium, Edwardsiella, Enterococcus, Bacillus, and Saccharomyces were freezedried under the abovementioned conditions. Their survival rates were 2.3­95.1%. Conclusion: Collectively, our results supported that the protectant mixture and parameters were beneficial for lyophilization of marine bacteria

How drying methods can influence the characteristics of mucilage obtained from chia seed and psyllium husk / Como os métodos de secagem podem influenciar as características da mucilagem obtida de sementes de chia e casca de psyllium

ABSTRACT: The influence of drying methods (oven drying at 50 °C, and freeze drying) on the centesimal composition, functional characteristics and rheological properties of mucilage obtained from chia seed and psyllium husk were investigated. Results showed that high temperature of oven drying reduced fiber content, solubility, emulsion activity and emulsion stability of mucilage. All samples showed pseudo plastic behavior, with the best result produced by Heschel-Bulkley and Power Law models of chia and psyllium mucilage, respectively. These results will be helpful in selecting suitable drying methods depending on the functional and rheological properties desired of the chia and psyllium mucilage in a food product.

RESUMO: Este estudo teve como objetivo avaliar a influência dos métodos de secagem (secagem em estufa a 50 °C e liofilização) sobre a composição centesimal, características funcionais e propriedades reológicas da mucilagem obtida a partir de sementes de chia e casca de psyllium. Os resultados mostraram que a alta temperatura de secagem em estufa reduziu o teor de fibras, a solubilidade, a atividade da emulsão e a estabilidade da emulsão das mucilagens. Todas as amostras apresentaram comportamento pseudoplástico, com o melhor ajuste produzido pelos modelos Heschel-Bulkley e Power Law das mucilagens de chia e psyllium, respectivamente. Estes resultados serão úteis na seleção do método de secagem adequado, dependendo das propriedades funcionais e reológicas desejadas das mucilagens de chia e psyllium.

Extracción y encapsulación de compuestos fenólicos provenientes de cascarilla de arroz / Extraction and encapsulation of phenolic compounds from rice hus

RESUMEN En la actualidad, el aprovechamiento de los subproductos agroindustriales es de vital importancia. El objetivo del presente trabajo fue estudiar una alternativa de valorización de la cascarilla de arroz, mediante la extracción y la encapsulación de compuestos fenólicos provenientes de las cascarillas. Este proceso fue llevado a cabo en un reactor batch con agitación mecánica a 453,15 K y 1 MPa durante 1 h, se usó agua como solvente. Se evaluó la micro-encapsulación de los componentes del extracto mediante liofilización usando como material encapsulante maltodextrina en diferentes proporciones. Los extractos acuosos mostraron un pH de 3,7, contenido de compuestos fenólicos de 8,2 mg equivalentes de ácido gálico/g de cascarilla, y una actividad antioxidante de 14,6 mg Eq.trolox/g de cascarilla. Mediante análisis de espectroscopía de infrarrojo se identificaron bandas representativas de grupos funcionales presentes en los compuestos fenólicos, reconocidos por su actividad antioxidante. La eficiencia de encapsulación fue de 99,8 % usando 14,3 % de maltodextrina, se obtuvieron cápsulas con 10,08 mg fenoles/g de encapsulado y un tamaño de partícula adecuado para la liberación y retención de los compuestos fenólicos de 63 μm. Posteriormente, se estudió la estructura semicristalina de las cápsulas mediante difracción de rayos X. Como conclusión, estas microcápsulas antioxidantes pueden ser adecuadas para su utilización en la industria farmacéutica o de alimentos como componente de envases alimentarios.

SUMMARY Currently, the use of agro-industrial by-products is of vital importance. The aim of the present work was to study an alternative of valorisation of the rice husk, by extraction and encapsulation of phenolic compounds from the husks. This process was carried out in a batch reactor with mechanical stirring at 453.15 K and 1 MPa for 1 h, water was used as the solvent. Microencapsulation of the extract components was evaluated by lyophilisation using maltodextrin at different proportions as encapsulating material. The aqueous extracts showed a pH of 3.7, contained phenolic compounds of 8.2 mg gallic acid/g of husk, and an antioxidant activity of 14.6 mg Eq.trolox/g of husk. By infrared spectroscopy analysis, representative bands of functional groups present in the phenolic compounds, recognised for their antioxidant activity, were identified. The encapsulation efficiency was 99.8 % using 14.3 % maltodextrin; capsules were obtained with 10.08 mg phenols/g capsules and a particle size suitable for the release and retention of phenolic compounds of 63 μm. Subsequently, the semi-crystalline structure of the capsules was studied by X-ray diffraction. To conclude, these antioxidant microcapsules may be suitable for use in the pharmaceutical or food industry as a component of food packaging.

Influence of different drying techniques on drying parameters of mango

Abstract This research inspected the effects of freeze, microwave (120 and 350 W) and hot air (60, 70 and 80 °C) drying techniques on the color, drying characteristics, antioxidant capacity and total phenolic content of mango slices. Midilli et al., Two-term and Page models which exemplify drying characteristics are superior than alternative models. All of the color values (a, b, L, C, α and ΔE) were altered notably based on the used drying technique and colors nearest to the fresh sample were attained with freeze drying. In comparison to the fresh sample, the dried samples showed a decrease of 18.4-54.6% in antioxidant capacity. The total phenolic content value was notably highest one for the microwave dried sample at 350 W and the lowest one for a hot air dried sample at 80 °C (P<0.05). This research showed that microwave drying at 350 W is able to yield high-quality mango slices with the extra advantage of shortened drying time in relation to hot air and freeze drying.

Effect of drying method on mechanical, thermal and water absorption properties of enzymatically crosslinked gelatin hydrogels

ABSTRACT Enzymatically crossliked gelatin hydrogel was submitted to two different drying methods: air drying and freeze drying. The resulting polymeric tridimensional arrangement (compact or porous, respectively) led to different thermal and swelling properties. Significant differences (p < 0.05) on thermal and mechanical characteristics as well as swelling in non-enzymatic gastric and intestinal simulated fluids (37 ºC) were detected. Water absorption data in such media was modelled according to Higuchi, Korsmeyer-Peppas, and Peppas-Sahlin equations. Freeze dried hydrogel showed Fickian diffusion behavior while air dried hydrogels presented poor adjustment to Higuchi model suggesting the importance of the relaxation mechanism at the beginning of swelling process. It was possible to conclude that the same gelatin hydrogel may be suitable to different applications depending on the drying process used.

NaCl stress impact on the key enzymes in glycolysis from Lactobacillus bulgaricus during freeze-drying

Abstract The viability of Lactobacillus bulgaricus in freeze-drying is of significant commercial interest to dairy industries. In the study, L.bulgaricus demonstrated a significantly improved (p < 0.05) survival rate during freeze-drying when subjected to a pre-stressed period under the conditions of 2% (w/v) NaCl for 2 h in the late growth phase. The main energy source for the life activity of lactic acid bacteria is related to the glycolytic pathway. To investigate the phenomenon of this stress-related viability improvement in L. bulgaricus, the activities and corresponding genes of key enzymes in glycolysis during 2% NaCl stress were studied. NaCl stress significantly enhanced (p < 0.05) glucose utilization. The activities of glycolytic enzymes (phosphofructokinase, pyruvate kinase, and lactate dehydrogenase) decreased during freeze-drying, and NaCl stress were found to improve activities of these enzymes before and after freeze-drying. However, a transcriptional analysis of the corresponding genes suggested that the effect of NaCl stress on the expression of the pfk2 gene was not obvious. The increased survival of freeze-dried cells of L. bulgaricus under NaCl stress might be due to changes in only the activity or translation level of these enzymes in different environmental conditions but have no relation to their mRNA transcription level.

Freeze-drying of ampicillin solid lipid nanoparticles using mannitol as cryoprotectant

abstract Solid lipid nanoparticles (SLNs) are interesting colloidal drug-delivery systems, since they have all the advantages of the lipid and polymeric nanoparticles. Freeze-drying is a widely used process for improving the stability of SLNs. Cryoprotectants have been used to decrease SLN aggregations during freeze-drying. In this study Ampicillin was chosen to be loaded in a cholesterol carrier with nano size range. To support the stability of SLNs, freeze-drying was done using mannitol. Particle size, drug release profile and antibacterial effects were studied after freeze-drying in comparison with primary SLNs. Preparations with 5% mannitol showed the least particle size enlargement. The average particle size was 150 and 187 nm before and after freeze-drying, respectively. Freeze-drying did not affect the release profile of drug loaded nanopartilces. Also our study showed that lyophilization did not change the antimicrobial effect of ampicillin SLNs. DSC analysis showed probability of chemical interaction between ampicillin and cholesterol.

resumo Nanoparticulas lipídicas sólidas (NLSs) são sistemas coloidais de liberação interessantes, uma vez que reúnem todas as vantagens de nanopartículas lipídicas e poliméricas. A liofilização é um processo amplamente utilizado para melhorar a estabilidade das NLSs e os crioprotetores têm sido usados para diminuir a agregação destas durante esse processo. Neste estudo, a ampicilina foi escolhida para ser encapsulada em um carreador de colesterol de escala nanométrica. Para manter a estabilidade das NLSs, a liofilização foi realizada utilizando-se manitol. O tamanho de partícula, o perfil de liberação do fármaco e os efeitos antibacterianos foram estudados após a liofilização em comparação com a NLSs primária. De acordo com os resultados, as preparações que contêm 5% de manitol mostraram o menor aumento do tamanho de partícula. Os resultados de tamanhos médio foram de 150 e 187 nm antes e depois da liofilização, respectivamente. O perfil de liberação prolongada, bem como o efeito antimicrobiano da ampicilina NLSs não foram alterados após a liofilização. A análise por DSC evidenciou provável interação entre a ampicilina e o colesterol.

Produtos derivados do camu-camu: efeito da secagem sobre elagitaninos e flavonoides, atividades antioxidante e antimicrobiana / Camu-camu ingredients: effect of drying on ellagitannins and flavonoids, and their antioxidant and antimicrobial activities

O camu-camu (Myrciaria dubia Mc. Vaugh) tem demonstrado ser um fruto promissor devido ao potencial funcional, principalmente pelo alto teor de vitamina C e compostos fenólicos, em especial elagitaninos. Este trabalho teve como objetivo avaliar os efeitos sobre os compostos fenólicos dos processos de secagem de polpa comercial de camu-camu, por leito de jorro e atomização (spray-drying), em diferentes temperaturas e concentrações de agentes carreadores, comparando-os com os do processo de liofilização. Os pós obtidos foram comparados em relação ao teor total de compostos fenólicos, ácido ascórbico e proantocianidinas. Além disso, avaliou-se o potencial benéfico à saúde através da determinação da capacidade antioxidante in vitro , atividade antimicrobiana e inibição das enzimas α-amilase, α-glicosidase e enzima conversora da angiotensina (ECA). Avaliou-se também proteção e regeneração celulares em modelo de planárias (Dugesia trigrina). Complementarmente, os pós de camu-camu foram adicionados em leite de soja, que foram fermentados com bactérias produtoras de ácido láctico (L. helveticus ATCC 12046 e L. plantarum NCDO 1193), para verificar sua funcionalidade quando incorporados como ingredientes em alimentos funcionais. Os resultados mostraram que a secagem da polpa acarretou em perdas significativas de compostos bioativos, na ordem ácido ascórbico>fenólicos totais> proantocianidinas, e spray-drying>leito de jorro>liofilização. Os compostos fenólicos detectados nos pós de camu-camu foram elagitaninos, ácido elágico, derivados de quercetina, ácido siríngico e miricetina, por LC-TOF-MS. A liofilização foi a melhor técnica de secagem para a preservação dos compostos fenólicos, e também da capacidade antioxidante e de inibição enzimática. Além disso, os pós liofilizados e atomizado (contendo 6% goma arábica a 120 °C) foram mais efetivos contra Staphylococcus aureus que a ampicilina. Os extratos desses pós demostraram potencial para proteção celular e rejuvenescimento no modelo de planárias. E por último, o leite de soja enriquecido com o pó de camu-camu resultou em um produto com maior teor de fenólicos, alta capacidade antioxidante e propriedades anti-hiperglicêmica e anti-hipertensiva. Portanto, os pós de camu-camu são ricos em compostos fenólicos e tem potencial para serem acrescentados como ingredientes em alimentos para o controle dos estágios iniciais de diabetes tipo 2 e complicações associadas

Camu-camu (Myrciaria dubia Mc. Vaugh) has demonstrated promising perspectives as a functional food, mainly due to high vitamin C and phenolic compounds contents, in particular ellagitannins. This study aimed to evaluate the effect of different drying processes (spouted bed drying, spray-drying) at selected temperatures and carrier concentrations, comparing to freeze-drying, on the contents and composition of phenolic compounds. The pulp powders were compared in relation to phenolic profiles, ascorbic acid and proanthocyanidins contents. Further, functional health potential was evaluated such as in vitro antioxidant capacity, antimicrobial activity and inhibition of α-amylase, α-glucosidase and angiotensin converting enzyme (ACE). It was also investigated cellular protection and regeneration in planaria (Dugesia trigrina) model. Additionally, camu-camu powders were added into soymilk and were fermented by lactic acid bacteria (L. helveticus ATCC 12046 and L. plantarum NCDO 1193) to verify their functionality as a functional food ingredient. The results showed that drying of the pulp led to significant losses of bioactive compounds, in the order ascorbic acid>total phenolics>proanthocyanidins, and spray-drying>spouted bed drying>freeze-drying. Phenolic compounds, such as ellagitannins, ellagic acid, quercetin derivatives, syringic acid and myricetin were detected in camu-camu by LC-TOF-MS. The freeze-drying was the best technique to preserve phenolic compounds, and also antioxidant capacity and enzyme inhibition. Besides that, freeze-dried and spray-dried (6% arabic gum at 120 °C) powders were more effective against Staphylococcus aureus than ampicillin. The extracts of those powders have desmonstrated potential to cellular protection and rejuvenation in planaria model. Finally, soymilk enriched with camu-camu powders resulted in more phenolic contents, high antioxidant capacity and anti-hyperglycemia and anti-hipertension properties product. To sum up, camu-camu powder is rich in phenolic bioactive profiles has potential as part of dietary strategies in the management of early stages of type 2 diabetes and associated complications

Optimización experimental del proceso de liofilización de uchuva adicionada con componentes activos por impregnación al vacío / Experimental optimization of the freeze dry process of cape gooseberry added with active compounds by vacuum impregnation

Antecedentes: Los procesos de optimización experimental, representan una herramienta efectiva para el mejoramiento de la calidad de los productos, contribuyendo en la diversificación de productos en la cadena de uchuva, como frutos promisorios de exportación. Objetivo: El objetivo del estudio fue optimizar el proceso de liofilización para obtener uchuvas (Physalis peruviana L.) semiesféricas adicionadas con componentes activos y de excelentes atributos de calidad. Métodos: Las muestras semiesféricas (3 - 4 g) fueron tratadas inicialmente por impregnación al vacío con una emulsión que contenía proteína de soja, sucralosa, tensoactivos, calcio, vitamina D3 (Colecalciferol), vitamina E (DL-α-tocoferol acetato) y vitamina B9 . La optimización experimental del proceso de liofilización se realizó con un diseño factorial 22 con el fin de determinar la condición óptima de operación, utilizando como variables independientes la velocidad de calentamiento de la placa (ºC/min) y el tiempo de sostenimiento a la temperatura de la placa para cada segmento del proceso y como variables dependientes: concentración de los componentes con actividad fisiológica, actividad de agua, humedad, textura, color y tiempo total de proceso. Resultados: Se identificó una influencia de las condiciones del proceso sobre las variables de respuesta, donde una porción de 49 g de uchuvas liofilizadas alcanzó contenidos superiores al 20% del valor diario de referencia de vitamina D y entre el 10 y 20% del valor diario de referencia en calcio y vitaminas B9, C y E; permitiendo identificar al producto como "Excelente fuente de vitamina D" y "Buena fuente de calcio y vitaminas B9, C, E", según la normativa colombiana. La condición óptima de proceso se alcanzó a una velocidad de calentamiento de placa de 0,04 ºC/min y un tiempo de sostenimiento de la temperatura de la placa de 1,2 h. Conclusiones: La aplicación integrada de procesos de impregnación al vacío y liofilización, representan una alternativa importante en el desarrollo de alimentos funcionales en el fruto de uchuva.

Introduction: Experimental optimization processes represent an effective tool for improving the quality of products, contributing to the diversification of products in the agricultural value chain of cape gooseberry, as promising export fruit. Aim: The aim of this study was to optimize the freeze-drying process to obtain hemispherical cape gooseberries (Physalis peruviana L.) with added active compounds, and with excellent quality attributes. Methods: The hemispherical samples (3 - 4 g) were initially treated by vacuum impregnation with an emulsion containing soybean protein, sucralose, surfactants, calcium, vitamin D3 (cholecalciferol), vitamin E (DL-α-tocopherol acetate) and vitamin B9. The experimental optimization of the freeze-drying was performed using a factorial design 22 to determine the optimum operating condition, using as independent variables the rate of heating plate (°C/min) and holding time at the temperature of the plate for each segment of the process and as dependent variables: concentration of physiologically active components, water activity, moisture content, texture, color and total processing time. Results: An influence of process conditions on the response variables was identified, where a portion of 49 g of freeze-dried gooseberries reached over 20% content of daily reference value (DRV) of vitamin D and between 10 and 20% of DRV in calcium and vitamin B9, C and E; allowing to identify the product as "Excellent source of vitamin D" and "Good source of calcium and vitamin B9, C, E", according to Colombian regulations. The optimal process condition was reached at a 0.04 °C/min heating rate of plate and a 1.2 h holding time of the plate temperature. Conclusions: The application of the integrated processes of vacuum impregnation and freeze-drying show an important technological alternative to development of functional foods from the fruit of cape gooseberry.

Physical characterization of freeze-dried foam prepared from Aloe Vera gel and guar gum / Caracterización de espumas liofilizadas preparadas a partir de gel de Aloe vera y goma guar

Background: Foams are colloidal dispersions of a gas suspended in a dispersing phase, which consisting of a semi-freeze-dried or viscous liquid phase. The physical properties of food foams are the result of the bubble characteristics and their spatial arrangement. Objectives: The aim of this work was to obtain foams of A. vera gel and guar gum and describe the changes in their physical properties and microstructure during freeze-drying using the fractal dimension concept and image analysis techniques. Methods: The porosity, density, and volume expansion factor of the fresh foams that were based on the A. vera foams were determined. The kinetics of foam texture, color, porosity and microstructure of the freeze-dried foams were obtained. The fractal texture dimension of surface (FDSDBC) and microstructure (FDESEM) of the foams were determined as indicators of structural changes after freeze-drying. The guar gum concentrations used to obtain the A. vera prefoam were expressed in w/w as F1 (control sample without gum), F2 (2%), F3 (4%) and F4 (6%). Results: We obtained stable freeze-dried foams of Aloe vera gel and guar gum. The porosity, density and volume expansion factor of the fresh and freeze-dried foams were affected by the addition of the guar gum. Changes in the topology of the freeze-dried foam surface during the drying process resulted in a high rugosity compared with the original smooth surface. The microstructure of the dried foam samples suggested a relationship between the gum concentration of the prefoam A. vera gel mixture and the physical properties before and after freeze-drying, such as an increase in the microstructural alterations and surface roughness during freeze-drying. The roughness of the freeze-dried foam surface, described by the FDSDBC represented the macroscopic physical changes of the samples and correlated with the changes in the foam microstructure, which were described by the fractal dimension of the Environmental Scanning Electron Microscopy ESEM microphotographs (FDESEM). Conclusions: The digital analysis of the structure and porosity of the freeze-dried foam can be used to quantify the effect of gum concentrations on the morphological features and physical properties of foams during freeze-drying.

Antecedentes: Las espumas son dispersiones coloidales de un gas en una fase líquida viscosa. Las propiedades físicas de las espumas alimentarias son el resultado de las características de sus burbujas y su disposición espacial. Objetivos: El objetivo de este trabajo fue obtener espumas de gel de A. vera y goma guar y describir los cambios en sus propiedades físicas y su microestructura durante el secado por liofilización utilizando el concepto de dimensión fractal y las técnicas de análisis de imagen. Métodos: Se determinó la porosidad, densidad, factor de expansión volumétrico de las espumas frescas de A. vera. Así como la cinética de liofilización, textura, isotermas de sorción, color, porosidad y la microestructura las espumas liofilizadas. La dimensión fractal de la textura (FDSDBC) y microestructural (FDESEM) de las espumas de gel de A. vera y goma guar liofilizadas se determinó como un indicador de los cambios estructurales después de la liofilización. Las concentraciones de goma de guar utilizados para obtener la solución de clara de huevo preespuma se expresaron en w/w como F1 (muestra de control sin goma), F2 (2%), F3 (4%) y F4 (6%). Resultados: Fue posible obtener espumas liofilizadas estables de gel de A. vera y goma guar. La porosidad, densidad, factor de expansión volumétrico de las espumas se vieron afectadas con la adición de goma guar. Los cambios en la topología de la superficie de la espuma liofilizada durante todo el proceso de secado dieron lugar a alta rugosidad en comparación con la superficie lisa original. La microestructura de las muestras de espuma secas sugirió una relación entre la concentración de goma de las espumas de A. vera y las propiedades físicas antes y después de la liofilización como un aumento en las alteraciones microestructurales y rugosidad de la superficie durante el secado por congelación. La rugosidad de la superficie de la espuma liofilizada, se describió por la relación FDSDBC que representa los cambios físicos macroscópicos de las muestras y se correlacionó con los cambios en la microestructura de espuma, que fueron descritos por la dimensión fractal de las micrografías ESEM (FDESEM). Conclusiones: El análisis digital de la estructura y la porosidad de la espuma liofilizada se puede utilizar para cuantificar el efecto de las concentraciones de goma guar en las características morfológicas de las espumas durante el secado por congelación.

Effect of freeze-drying and production process on the chemical composition and fatty acids profile of avocado pulp / Efecto del liofilizado y del proceso de producción en la composición química y el perfil de ácidos grasos de la pulpa de aguacate

Freeze-drying technology is the best dehydration process to preserve shelf-life and allowing avocado to maintain its sensorial and nutritional characteristics. The aim of this work was to determine if the freeze-drying and production condition have an effect on the nutritional quality of the avocado pulp grown in rain-fed and irrigation orchards. Four treatments were applied: non-freeze-dried rain-fed fruits, non-freeze-dried irrigation fruits, freeze-dried rain-fed fruits and freeze-dried irrigation fruits. Results showed that the fruit is made up of 71.4%, 16%, and 12.6% pulp, seed and skin, respectively. The pulp is made up of 71.51%, 19.96%, 2.81%, 0.51% and 1.51% water, lipids, ashes, crude fiber and protein, respectively. Avocado oil is composed by 61%, 18.8%, 11.6% and 7% oleic, palmitic, linoleic, and palmitoleic fatty acids, respectively. The freeze-drying decreased the linoleic acid by 1.43 g/100g. Under rain-fed conditions 4% and 13% less total fat and oleic fatty acid are produced than in irrigation conditions. We conclude that freeze-dried avocado pulp shows slight changes in their nutritional quality.

La tecnología de liofilización es el mejor proceso de deshidratación para mantener mayor vida de anaquel y conservar las propiedades nutricionales y sensoriales de la pulpa del aguacate. El objetivo de este estudio fue determinar si el liofilizado y condición de producción tienen un efecto sobre la calidad nutrimental de la pulpa de aguacate cultivado en huertas de riego y temporal. Se aplicaron 4 tratamientos: frutos de temporal no liofilizado, frutos de riego no liofilizado, frutos liofilizados de temporal y frutos liofilizados de riego. Los resultados muestran que el fruto está compuesto por 71.39, 16 y 12.6% de pulpa, hueso y cascara respectivamente. La pulpa está compuesta por 71.51, 19.96, 2.81, 0.51 y 1.5 % de humedad, lípidos, cenizas, fibra cruda y proteína, respectivamente. El aceite del aguacate está constituido de 61. 18.8, 11.6 y 7% de ácidos grasos oleico, palmítico, linoléico y palmitoleico, respectivamente. El liofilizado disminuyó 1.43 g/100 g de ácido linoléico. Bajo condiciones de temporal se produce 4 y 13% menos grasa total y ácido graso oleico que en condiciones de riego. Se concluye que la pulpa del aguacate liofilizada presenta ligeros cambios en su calidad nutrimental.

Evaluation of three methods for preservation of Azotobacter chroococcum and Azotobacter vinelandii

La preservación de bacterias es asunto de granimportancia debido a que muchas de ellas son usadas enprocesos biotecnológicos que requieren mantener su viabilidad ypropiedades genéticas. En este estudio, se evaluaron tres métodospara la preservación de A. chroococcum C26 y A. vinelandii C27;criopreservación, liofilización, e inmovilización en polímerossecos, durante 60, 30 y 60 días, respectivamente. A su vez, seestudió el efecto de tres agentes protectivos para la liofilizacióny para la criopreservación y cuatro polímeros. La eficiencia delos métodos fue evaluada contando células viables y midiendoactividad como fijación de nitrógeno. Los resultados mostraronque la mejor técnica, la cual mantuvo la viabilidad y la actividad,fue la liofilización, seguida por inmovilización y criopreservación.La liofilización mantuvo estable la habilidad bacteriana para fijarnitrógeno, la tasa de sobrevivencia bacteriana (TSB) fue superioral 80%; y el mejor resultado se evidenció cuando se usó S/BSAcomo agente protectivo. La inmovilización mantuvo la BSRsuperior al 80%, y la fijación de nitrógeno fue disminuida en 20%.La criopreservación tuvo pérdida sustancial de viabilidad para C26(TSB aprox. 70%); mientras que C27 se preservó bien. La fijaciónde nitrógeno fue significativamente disminuida para ambas cepasindependientemente del agente crioprotectivo usado (P < 0.05).Los resultados sugieren que el éxito de los métodos de preservaciónpara Azotobacter depende de la técnica, el agente protectivo y la cepausada; siendo la liofilización con S/BSA la técnica con mejoresresultados para preservar las bacterias de este género...

Because the use of bacteria for biotechnological processes requires maintaining their viability and geneticstability, preserving them becomes essential. Here, we evaluated three preservation methods for A.chroococcum C26 and A. vinelandii C27; preservation methods: cryopreservation and immobilization in drypolymers for 60 days, and freeze-drying for 30. We evaluated their efficiency by counting viable cells andmeasuring nitrogen fixation activity. Additionally, we assessed the effect of three protective agents forfreeze-drying, three for cryopreservation, and four polymers. Freeze-drying proved the best technique tomaintain viability and activity, followed by immobilization and cryopreservation. Bacterial nitrogen fixingability remained unchanged using the freeze-drying method, and bacterial survival exceeded 80%; S/BSAwas the best protective agent. Immobilization maintained bacterial survival over 80%, but nitrogen fixationwas decreased by 20%. Lastly, cryopreservation resulted in a dramatic loss of viability for C26 (BSRapprox. 70%), whereas C27 was well preserved. Nitrogen fixation for both strains decreased regardless ofthe cryoprotective agent used (P < 0.05). In conclusion, the success of Azotobacter preservation methodsdepend on the technique, the protective agent, and the strain used. Our results also indicated that freezedryingusing S/BSA is the best technique to preserve bacteria of this genus...

Porque o uso de bactérias para processos biotecnológicos,requer a manutenção da sua viabilidade e estabilidade genética,preserva-las é essencial Avaliaram-se três métodos de preservação deA. chroococcum C26 e A. vinelandii C27; criopreservação, liofilização, eimobilização de polímeros secos. Examinamos também o efeito deagentes protetores para liofilizar, para a criopreservação, e polímeros.A eficiência foi avaliada contando as células viáveis e medindoa atividade como a fixação do azoto. Os resultados mostraramque a melhor técnica foi a liofilização seguida de imobilização ecriopreservação. A liofilização manteve inalterada a capacidadeda bactéria para fixar o azoto, e o melhor resultado foi observadoquando se usou S/BSA como agente protetor. A criopreservaçãoresultou em uma perda dramática de viabilidade para C26 (TSBaprox. 70%.), enquanto que C27 foi bem preservada. A fixaçãode azoto foi significativamente diminuída para ambas as estirpes,independentemente do agente crioprotector utilizado (P < 0.05).Em conclusão, os resultados sugerem que o êxito dos métodosde conservação de Azotobacter dependem da técnica, do agente deproteção, e da estirpe utilizada, sendo a liofilizacao com S/BSA amelhor técnica para preservar as bactérias deste género...

Bench surgical training with lyophilized esophageal segments

PURPOSE: To present lyophilized esophageal segments that can be used to learn surgical skills. METHODS: Four esophagus were harvested from four non-esophagus related research dogs at the moment of euthanasia. Each esophagus was trimmed in 3 cm long segments. They were lyophilized and stored during 30 days. The day programmed for surgical skills practice, they were rehydrated. RESULTS: Sixteen segments have been used. After rehydrating, all the segments kept their normal anatomic shape and structural integrity. One incision was made on every esophageal segment and sutured with running stitches of 3-0 polyglactin 910. There were no complications, such as tissue tears, nor esophageal hardening. CONCLUSIONS: The lyophilized esophagus is a high fidelity, practical, reproducible, portable, low-cost bench model. It allows general surgery apprentices to learn how to handle an esophagus, as well as to perfect their surgical and suture abilities before applying them on real patient's esophagus.

Estudo in vivo do comportamento de bioprótese liofilizada: seguimento de 3 meses em carneiros jovens / In vivo study of lyophilized bioprostheses: 3 month follow-up in young sheep

OBJETIVO: Para melhorar as propriedades mecânicas e imunogênicas, o glutaraldeído é utilizado no tratamento do pericárdio bovino que é utilizado em biopróteses. A liofilização do pericárdio bovino tratado com glutaraldeído diminui os radicais aldeído, com provável redução do potencial para calcificação. O objetivo deste estudo é avaliar os efeitos da liofilização em biopróteses valvares de pericárdio bovino como mecanismo protetor na diminuição da disfunção estrutural valvar. MÉTODOS: Foi realizado o implante de biopróteses de pericárdio bovino tratado com glutaraldeído, liofilizadas ou não, em carneiros de 6 meses de idade, sendo os animais eutanasiados com 3 meses de seguimento. As biopróteses foram implantadas em posição pulmonar, com auxílio de circulação extracorpórea. Um grupo controle e outro grupo liofilizado foram avaliados quanto ao gradiente ventrículo direito/artéria pulmonar (VD/AP) no implante e explante; análise quantitativa de cálcio; inflamação; trombose e pannus. O nível de significância estabelecido foi de 5%. RESULTADOS: O gradiente médio VD/AP, no grupo controle, no implante, foi 2,04 ± 1,56 mmHg e, no grupo de liofilização, foi 6,61 ± 4,03 mmHg. No explante, esse gradiente aumentou para 7,71 ± 3,92 mmHg e 8,24 ± 6,2 mmHg, respectivamente, nos grupos controle e liofilização. O teor de cálcio médio, após 3 meses, nas biopróteses do grupo controle foi 21,6 ± 39,12 µg Ca+2/mg de peso seco, em comparação com um teor médio de 41,19 ± 46,85 µg Ca+2/mg de peso seco no grupo liofilizado (P = 0,662). CONCLUSÃO: A liofilização de próteses valvares com pericárdio bovino tratado com glutaraldeído não demonstrou diminuição da calcificação neste experimento.

OBJECTIVE: Glutaraldehyde is currently used in bovine pericardium bioprosthesis to improve mechanical and immunogenic properties. Lyophilization is a process that may decrease aldehyde residues in the glutaraldehyde treated pericardium decreasing cytotoxicity and enhancing resistance to calcification. The aim of this study is to evaluate bioprosthetic heart valves calcification in adolescent sheep and to study the potential of lyophilization as a mechanism to protect calcification. METHODS: Two groups were evaluated: a control group in which a bovine pericardium prosthetic valve was implanted in pulmonary position and a lyophilized group in which the bovine pericardium prosthetic valve was lyophilized and further implanted. Sixteen sheeps 6 months old were submitted to the operation procedure. After 3 months the sheeps were euthanized under full anesthesia. RESULTS: Six animals of the control group reached 95.16 ± 3.55 days and six animals in the lyophilized group reached 91.66 ± 0.81 days of postoperative evolution. Two animals had endocarditis. Right ventricle/pulmonary artery (RV/PA) mean gradient, in the control group, at the implantation was 2.04 ± 1.56 mmHg, in the lyophilization group, the RV/PA mean gradient, at the implantation was 6.61 ± 4.03 mmHg. At the explantation it increased to 7.71 ± 3.92 mmHg and 8.24 ± 6.25 mmHg, respectively, in control and lyophilization group. The average calcium content, after 3 months, in the control group was 21.6 ± 39.12 µg Ca+2/mg dry weight, compared with an average content of 41.19 ± 46.85 µg Ca+2/mg dry weight in the lyophilization group (P=0.662). CONCLUSION: Freeze drying of the bovine pericardium prosthesis in the pulmonary position could not demonstrate calcification mitigation over a 3 month period although decreased inflammatory infiltration over the tissue.

Enxerto bovino liofilizado: comportamento histológico após seguimento de 49 meses em seres humanos / Bovine lyophilized graft (BLG): histological analysis on behavior in humans after 49 months

OBJETIVO: Analisar o comportamento histológico do ELB, produzido conforme protocolo desenvolvido pelo autor principal, em seres humanos no decorrer de 49 meses através da aferição da proporção enxerto/osso neoformado em relação ao total de área mineralizada. MÉTODOS: Série de casos com 12 pacientes, oito femininos (66%) e quatro masculinos (34%), totalizando 13 biópsias, nos quais utilizou-se ELB e que posteriormente houve necessidade de reintervenção cirúrgica, no período de 2000 a 2011. As lâminas produzidas, coradas com hematoxilina-eosina (HE), foram analisadas por patologista e digitalizadas para a avaliação proposta. RESULTADOS: A média etária foi de 57 anos e o tempo médio de seguimento de 49 meses (6-115). A proporção média de ELB foi de 42% (13-85) e de osso neoformado de 58% (15-87) em relação ao total de área mineralizada. CONCLUSÕES: O presente estudo demonstra que o ELB utilizado apresenta característica osteocondutora e biocompatibilidade. O ELB apresentado é opção terapêutica a ser utilizada em cirurgias ortopédicas que necessitem preenchimento de deficiências ósseas.

OBJECTIVE: To analyze the histological behavior of bovine lyophilized grafts (BLG) produced according to a protocol developed by the first author, in humans over a 49-month period by measuring the graft/bone neoformation ratio in relation to the total mineralized area. METHODS: This was a case series involving 12 patients: eight females (66%) and four males (34%), totaling 13 biopsies. BLG was used, and surgical reintervention was subsequently required during the period 2000 to 2011. The slides produced were stained with hematoxylin-eosin (HE), were analyzed by a pathologist and were digitized for the proposed evaluation. RESULTS: The mean age was 57 years and the mean follow-up was 49 months (range: 6-115). The average proportion of BLG was 42% range: 13-85) and neoformed bone, 58% (range: 15-87) in relation to the total area mineralized. CONCLUSIONS: This study demonstrated that the BLG used presented osteoconductive characteristics and biocompatibility. BLG is a therapeutic option that can be used in orthopedic surgery in which bone defects need to be filled.

Freeze-drying microscopy in mathematical modeling of a biomaterial freeze-drying

Transplantation brings hope for many patients. A multidisciplinary approach on this field aims at creating biologically functional tissues to be used as implants and prostheses. The freeze-drying process allows the fundamental properties of these materials to be preserved, making future manipulation and storage easier. Optimizing a freeze-drying cycle is of great importance since it aims at reducing process costs while increasing product quality of this time-and-energy-consuming process. Mathematical modeling comes as a tool to help a better understanding of the process variables behavior and consequently it helps optimization studies. Freeze-drying microscopy is a technique usually applied to determine critical temperatures of liquid formulations. It has been used in this work to determine the sublimation rates of a biological tissue freeze-drying. The sublimation rates were measured from the speed of the moving interface between the dried and the frozen layer under 21.33, 42.66 and 63.99 Pa. The studied variables were used in a theoretical model to simulate various temperature profiles of the freeze-drying process. Good agreement between the experimental and the simulated results was found.

A prática da transplantação traz esperança para muitos pacientes. Uma visão multidisciplinar nessa área visa à produção de tecidos biológicos para serem utilizados como implantes e próteses. A liofilização é um processo de secagem que preserva características essenciais desses materiais, facilitando sua manipulação e armazenamento. A liofilização é um processo que requer muito tempo e energia e sua otimização é muito importante, pois permite reduzir custos de processo melhorando a qualidade do produto. A modelagem matemática é uma ferramenta que permite descrever o comportamento do produto durante o processo e, consequentemente, auxilia os estudos de otimização. Microscopia óptica acoplada à liofilização, uma técnica usualmente aplicada na determinação de temperaturas críticas de formulações líquidas, foi utilizada neste trabalho na determinação de taxas de sublimação da liofilização de um tecido biológico. As taxas de sublimação foram calculadas a partir da velocidade da interface entre a camada seca e congelada, sob pressões de 21,33, 42,66 e 63,99 Pa. As variáveis estudadas foram usadas em um modelo matemático teórico, que simula os perfis de temperatura do produto durante o ciclo de liofilização. Os resultados apresentados demonstraram boa relação entre os dados experimentais e simulados.

Liofilização como alternativa para conservação do leite humano / Lyophilization as an alternative for conservation of breast milk

Objetivo - Os benefícios do aleitamento materno são bem descritos na literatura. Melhorar as condições de fornecimento acessível deste importante alimento a todos os lactentes é um desafio para o profissional nutricionista. Métodos - Amostras de leite humano procedentes do Banco de Leite da cidade de Taubaté, São Paulo, foram submetidas à liofilização, sendo congeladas em nitrogênio líquido a -210ºC e permanecendo no liofilizador por 24 horas. Após a liofilização as amostras foram analisadas e comparadas ao leite in natura quanto a alguns nutrientes: lipídeos por extração direta em extrator Soxhlet, glicídios redutores em lactose por titulação, proteínas por metodologia semimicro de Kjeldahl, cálcio por titulação e imunoglobulinas por eletroforese em gel de agarose com o objetivo de visualizar as bandas gama. Também foram realizadas provas de reconstituição diluindo 30g de cada amostra em 100mL de água filtrada. As análises foram realizadas em triplicata e em seguida analisadas estatisticamente. Resultados - As triplicatas analisadas apresentaram os teores de lipídeos, lactose, proteína e cálcio inalterados em comparação aos valores do leite não-liofilizado descrito na literatura. Quanto à restituição, a cor e a fluidez se mostraram semelhante ao leite in natura e a diluição foi plena. A eletroforese também demonstrou a presença da banda gama o que sugere a conservação de imunoglobulina. Conclusão - A técnica de liofilização mostrou-se muito favorável em relação a outras técnicas de conservação, já que a mesma não utiliza o aquecimento como fator determinante para diminuir a atividade de água e sim o estado físico da matéria: sublimação.

Objective - The benefits of breastfeeding have being reported in the literature. The improvement of the accessibility conditions to this important food to all infants is a challenge for the professional nutritionist. Methods - Samples of human breast milk were collected from Taubaté city, São Paulo. They were submitted to lyophilization and frozen in liquid nitrogen at -210 ºC and they were remained in lyophilizer during 24 hours. After the lyophilization, the milk was analyzed and compared with in natura milk with respect to the following nutrients: lipids by direct extraction in Soxhlet apparatus, reducing carbohydrates by titration in lactose, protein by semi-micro Kjeldahl methodology, calcium by titration and immunoglobulins by agarose gel electrophoresis in order to visualize the gamma bands. Tests of reconstitution were also carried out by diluting 30 g of dried milk in 100 mL of filtered water. The analyses were performed in triplicate and then analyzed statistically. Results - The triplicates analyzed presented levels of lipids, lactose, protein and calcium unchanged in comparison with the values of non-lyophilisate samples as described in the literature. In the restitution tests, the color and the fluidity were similar to in natura milk and the dilution was total. The electrophoresis also showed the presence of the gamma bands, that suggests the conservation of the immunoglobulin. Conclusion - The results showed that lyophilization process is favorable, compared with other conservation processes, since that is not based in the heating as the main factor to reduce the water activity, but the physical state of matter: sublimation.

Enhancing the aqueous solubility and dissolution of olanzapine using freeze-drying

The aim of the present study was to develop an olanzapine freeze-dried tablet (FDT). The solubility and dissolution rate of poorly water-soluble olanzapine was improved by preparing a freeze-dried tablet of olanzapine using the freeze-drying technique . The FDT was prepared by dispersing the drug in an aqueous solution of highly water-soluble carrier materials consisting of gelatin, glycine, and sorbitol. The mixture was poured in to the pockets of blister packs and then was subjected to freezing and lyophilisation. The FDT was characterised by DSC, XRD and SEM and was evaluated for saturation solubility and dissolution. The samples were stored in a stability chamber to investigate their physical stability. Results obtained by DSC and X-ray were analysed and showed the crystalline state of olanzapine in FDT transformation to the amorphous state during the formation of FDT. Scanning electron microscope (SEM) results suggest reduction in olanzapine particle size. The solubility of olanzapine from the FDT was observed to be nearly four and a half times greater than the pure drug. Results obtained from dissolution studies showed that olanzapine FDT significantly improved the dissolution rate of the drug compared with the physical mixture (PM) and the pure drug. More than 90 percent of olanzapine in FDT dissolved within 5 minutes, compared to only 19.78 percent of olanzapine pure drug dissolved over the course of 60 minutes. In a stability test, the release profile of the FDT was unchanged, as compared to the freshly prepared FDT after 90 days of storing.

O objetivo do presente estudo foi desenvolver comprimidos liofilizados de olanzapina (FDT). A solubilidade e a taxa de dissolução da olanzapina, fracamente solúvel em água, foram melhoradas com a preparação de comprimidos liofilizados de olanzapina usando a técnica de liofilização. O FDT foi preparado por dispersão do fármaco em solução aquosa de materiais altamente solúveis em água, como gelatina, glicina e sorbitol. A mistura foi colocada em blisters e, então, submetida ao congelamento e liofilização. O FDT foi caracterizado por DSC, Difração de Raios X e microscopia eletrônica de varredura(SEM) e avaliaram-se a solubilidade de saturação e a dissolução. As amostras for5am armazenadas em câmara de estabilidade para investigar a estabilidade física. Os resultados obtidos com DSC e Raios X foram analisados e mostraram a transformação do estado cristalino da olanzepina em FDT no estado amorfo durante a formação do FDT. Os resultados da SEM sugerem a redução do tamanho das partículas de olanzapina. A solubilidade da olanzapina do FDT melhorou significativamente a taxa de dissolução do fármaco comparativamente à mistura física (PM) e ao fármaco puro. Mais do que 90 por cento da olanzepina no FDT dissolveu em 5 minutos, comparativamente aos 19,78 por cento do fármaco puro dissolvido em 60 minutos. No teste de estabilidade, o perfil de liberação da FDT mostrou-se inalterado, quando comparado com o FDT recém-preparado, após 90 dias de armazenamento.