Development of an improved virus plaque assay based on avicel / 生物工程学报

Avicel is made of a mixture of microcrystalline cellulose (MCC) and carboxymethyl cellulose (CMC), and used for virus plaque assay. The avicel in common use is produced by FMC Biopolymer. Due to the relatively fixed proportion of MCC and CMC, avicel in common use is not suitable for plaque determination experiment of all types of viruses. In this study, we evaluated the effect of avicel made of different proportions of MCC and CMC on virus plaque assay, and developed an improved avicel virus plaque assay featured with simple and convenient operation, good practicability and high stability. To generate avicel overlays with different proportions of MCC and CMC, twelve different 2×avicel solutions were prepared. Their overall viscosity and bottom viscosity were measured to evaluate the ease of operation. The results showed that most of the 2×avicel solutions (except the 4.8% MCC+1.4% CMC and 4.8% MCC+1.0% CMC group) were easy to absorb and prepare nutrient overlap than 2×CMC solution. In order to find the best scheme to detect the titer of porcine epidemic diarrhea virus (PEDV), these avicel overlay solutions with different proportion of MCC and CMC were used as a replacement in the standard plaque assay. By comparing the size, clarity, stability and titer accuracy of virus plaque, we identified that 0.6% MCC and 0.7% CMC was the most preferable composition of avicel overlay for PEDV plaque assay. In conclusion, we developed an improved virus plaque assay based on avicel, which may facilitate the research of virus etiology, antiviral drugs and vaccines.

Enhancement of dissolution rate of racecadotril by liquisolid compact technology

Abstract The current investigation was used to improve the rate of dissolution of an anti-diarrheal drug i.e., racecadotril (RT) at low pH conditions (i.e., in the stomach) by reducing the water secretion and electrolyte in to the intestine by liquisolid tablets. Different formulations (liquisolid) were prepared using Avicel PH 102 as a carrier. Aerosil 200 as a coating material and sodium starch glycolate used as a disintegrant. Polyethylene glycol 200 was used as a non-volatile vehicle to dissolve the drug. FTIR, DSC, XRD and dissolution studies were conducted to characterise liquisolid tablets. Characterisation studies indicated that no interactions between carrier and drug. Solid state characterization had shown a reduction in crystallinity that further supports increment in solubility and dissolution. The optimised formulation showed a significant increase in dissolution i.e., 99.54±0.62% in 30 min compared to directly compressible tablets (38.47±0.26%). The % dissolution efficiency of racecadotril liquisolid tablets 76.86% compared to marketed tablet (27.56%) and conventional direct compression tablet (17.11%). Significant reduction in mean dissolution time of racecadotril from liquisolid tablets (6.84 min) compared to direct compression tablet (44.57 min), indicating faster release of drug and faster onset of action. Formulation of liquisolid tablets could enhance solubility, dissolution and bioavailability of racecadotril

Electrostatic and Water Content Effects on Yarrowia lipolytica Lipase Immobilization by Adsorption.

Aims: In the present investigation, an attempt has been made to explain lipase immobilization by adsorption on three minerals matrixes, i.e. Celite 545, Silica gel (60G) and Avicel (PH 101). Study Design: immobilization by absorption on minerals matrixes, water content by volumetric karl Fischer titration and surface potentials using a particle charge detector Mutek PCD 03 were used. Place and Duration of Study: Walloon Centre of Industrial Biology (CWBI) Unit of Bio- Industries, University of Liege, Gembloux Agro-Bio Tech, Passage des Deportes 2, B- 5030 Gembloux, Belgium between Jun 2012 and jun 2013. Methodology: A methodical order was developed whereby the influences of water content, surface potentials and pH, on immobilization by adsorption were explored. Adsorbed YLL was used to understand an interesterification reaction between rapeseed oil and milk fat in comparison with a commercial silica-granulated Thermomyces lanuginosus lipase (Lipozyme TL IM). Results: Maximum immobilization yield was obtained with Celite (70%) and the lowest with silica gel (29%). Total water content of free and immobilized lipase was determined by volumetric Karl Fischer titration. The water content of Silica gel was higher than the one of other supports. Water content of silica gel could prevent the enzyme fixation. These results could be explained by the adsorption being governed mainly by electrostatic interactions between the enzyme and matrix. This hypothesis was further reinforced by measurements of electrical potential. They showed a lowest negative potential of Silica gel after enzyme adsorption in comparison to Celite. Conclusion: From these results celite was designated as an efficient matrix to immobilize Yarrowia lipolytica lipase (YLL) by adsorption. This performed system was used to realize an interesterification reaction between rapeseed oil and milk fat in comparison with a commercial silica-granulated Thermomyces lanuginosus lipase (Lipozyme TL IM).

Extraction and characterization of microcrystalline cellulose obtained from the back of the fruit of Lageriana siceraria (water gourd).

The work was aimed to investigate the suitability of acid modified alpha cellulose obtained from the back of the fruit of Lageriana siceraria (water gourd) in production of pharmaceuticals, particularly solid dosage forms. Cellulose is the commonest Filler/Binder or disintegrant used in tablet formulation. Cellulose was extracted from the fruit of Lageriana siceraria and subjected to modification by controlled acid micronisation to produce microcrystalline cellulose (LS-MCC) using 2.5N hydrochloric acid and Avicel pH 101 was used as the basis for comparison. The powder and flow properties of the microcrystalline cellulose was investigated and the result of both the LS-MCC and Avicel pH 101compared. Microcrystalline cellulose (LS-MCC) displayed superior swelling and hydration capacities as compared to Avicel PH101 but lesser flow properties in view of its higher angle of repose, Carr’s and Hausner’s index.

Functionality of innovative and generic celluloses in metronidazole formulations / Funcionalidade de celuloses inovadores e genéricos em formulações de metronidazol

The wide variety of excipients available calls for evaluation of their functionality, in this case of the pharmaceutical performance of microcrystalline celluloses and sodium cross-linked carboxymethylcelluloses from different sources. This evaluation includes parameters such as powder flow, compactibility, ejection pressure and dissolution from fast-release tablets as well as from floating granules and controlled-release tablets. In a previous study, the excipient Carmacel® presented better disintegration properties compared to Croscarmellose®. However, the evaluation showed better compactibility performance for Croscarmellose®. These characteristics were observed using pure excipients. Nevertheless, these advantages have not been confirmed in tests employing immediate-release or modified-release formulations containing metronidazole. Regarding microcrystalline celluloses, the present comparative evaluation between pure Alfacel ® types 101 and 102 and pure Avicel® types 101 and 102 showed better compactibility performance for the latter. However, for metronidazole formulations, this advantage was not evident in the innovative excipient. Notwithstanding, this study revealed better compactibility performance of microcrystalline cellulose type 101. In terms of powder flow properties, Avicel® and Alfacel® showed similar performance. However, the results revealed better powder flow employing microcrystalline cellulose type 102 for both excipients. Based on the results obtained, it can be concluded that the employment of innovative and generic excipients have both advantages and disadvantages. The observed differences however, tend to disappear as the excipients are diluted in a formulation, thereby equalizing their influence on product performance.

A variedade de excipientes disponível no mercado requer adequada seleção desses no que se refere à sua funcionalidade, como no caso de celuloses microcristalinas (Avicel® 101 e 102 e Alfacel® 101 e 102) e de carboximetilceluloses de sódio reticuladas (Croscarmellose® e Carmacel®), provenientes de diferentes fontes. Assim sendo, o desempenho farmacotécnico desses excipientes deve ser avaliado quanto ao fluxo e característica de compactação do pó, à pressão de expulsão do núcleo, ao perfil de dissolução de comprimidos de liberação imediata e modificada assim como de grânulos flutuantes. Em um trabalho anterior, o excipiente Carmacel® apresentou melhores propriedades de desintegração quando comparado ao Croscarmellose®, porém, no que se refere à característica de compactação a avaliação revelou melhor desempenho para o Croscarmellose®. Tais características foram observadas empregando apenas os excipientes. Porém, tais vantagens não foram confirmadas nos ensaios empregando as formulações de liberação imediata ou de liberação modificada contendo metronidazol. No que se refere às celuloses microcristalinas, a avaliação comparativa entre Alfacel® puro dos tipos 101 e 102 e Avicel® puro dos tipos 101 e 102 revelou melhor desempenho desse último quanto à característica de compactação, no entanto, para as formulações contendo metronidazol não foi possível demonstrar tal vantagem para o excipiente inovador. Porém, o estudo revelou melhor desempenho quanto à característica de compactação da celulose microcristalina do tipo 101. Quanto às propriedades relativas ao fluxo de pó, o Avicel® e o Alfacel® apresentaram desempenho semelhante. Porém, o estudo revelou melhor fluxo de pó no emprego da celulose microcristalina do tipo 102, para ambos os excipientes. Considerando os resultados obtidos, pode-se concluir que o emprego dos excipientes inovador e genérico apresentam vantagens e desvantagens. No entanto, as diferenças observadas tendem a desaparecer em função da diluição desses na formulação, equalizando, dessa forma, sua influência no desempenho do produto.

Preliminary study on formalizing process of Changle Granule / 中成药

Objective:To screen better excipient and better ratio of the excipients and to improve the formability of the compound Chinese medicine Changle (Saliva Miltiorrhiza) and resistant to moisture of the granules. Methods: Through measuring the distribution of the size and the absorption of moisture of the granule the formability was determined. Under high moisture for a moment, the amount of absorption of moisture and the flowability of the granule was measured and the appearance was observed as to determine the nature of resistant to moiture of the granules. Results: The better excipients was soluble starch and avicel. It was better that the combined excipients of starch: avicel in a ratio of 1∶1 was mixed with the extract powder in a ratio of 2∶3. Conclusion: When the combined excipients of starch: avicel in a rato of 1∶1 was used, the extract powder was easy to be formed and the granule made was moisture-resistant.