Effect of Lyophilization on Stability of PEG-Protein Conjugate: A Case Study with Peginterferon alfa-2b

Abstract The purpose of the present study was to develop stable lyophilized formulation of peginterferon alfa-2b which is acquiescent to the short lyophilization process. The present study evaluates the effect of buffering components and cryoprotectant(s) on depegylation of the peginterferon alfa-2b in combination with lyophilization process. Finally, a short lyophilization process was identified which can produce a stable pharmaceutical form of peginterferon alfa-2b without any depegylation during long-term storage. Formulations were analyzed mainly for depegylation by HP-size exclusion chromatography and in-vitro antiviral activity. Residual moisture content in the lyophilized product was also used as a key indicating parameter to check its role with respect to depegylation upon storage under various temperature conditions. It was observed that the peginterferon alfa-2b when formulated in presence of cryoprotectant like sucrose requires longer lyophilization process of about 5 days, irrespective of the buffering components used, to reduce the level of residual moisture content and thereby to produce the stable formulation without depegylation. A stable formulation in presence of high concentration of lactose as a cryoprotectant was developed which can withstand stresses exerted to protein-polymer conjugate during lyophilization phases without any significant depegylation. A short lyophilization process of about 48 hours can be utilized for peginterferon alfa-2b when formulated in presence of lactose as a cryoprotectant through which a stable lyophilized formulation can be produced as against longer process required when sucrose is used a cryoprotectant, which is essential from commercial point of view as lyophilization is a costly process.

DMSO as new, counterintuitive excipient for freeze-drying human keratinocytes.

DMSO is widely used as powerful cryoprotectant for the storage and transport of frozen cells. Beyond this established application of DMSO, we could now show that it has also promising lyoprotectant effects in the field of lyophilisation of therapeutic cells. Freeze-drying of HaCaT keratinocytes in 10% HES, 5% HE and in presence of DMSO led to an increase in cell membrane integrity from 25.3 ± 2.7 % without DMSO to 41.4 ± 4.3 % with 2% DMSO, as determined by trypan blue exclusion. Interruption of the lyophilisation cycle at different sampling points showed a rapid decrease of cell membrane integrity below a critical residual moisture content. DMSO was able to stabilise cell membranes below this moisture level up to a final residual moisture content of less than 1%. Furthermore, DMSO increased the total protein content of cells after freeze-drying and subsequent SDS PAGE analysis indicated that certain abundant proteins were better preserved with the use of DMSO. Owed to its low vapour pressure, a significant part of DMSO is not removed during freeze-drying and remains as plasticiser in the lyophilised cake. However, a Tg above 60°C for 2% DMSO indicates that samples can still be stored at temperatures of 2-8°C. Also, no macroscopic or microscopic collapse can be observed by SEM or BET measurements and DMSO addition leads even to more elegant cakes with reduced cake cracking. With a better preservation of cell membranes and cellular structures, DMSO can contribute to the still unsolved problem of freeze-drying cells of higher complexity.

Impact of the freeze-drying process on product appearance, residual moisture content, viability, and batch uniformity of freeze-dried bacterial cultures safeguarded at culture collections.

In this study, causes of collapsed bacterial cultures in glass ampoules observed after freeze-drying were investigated as well as the influence of collapse on residual moisture content (RMC) and viability. Also, the effect of heat radiation and post freeze-drying treatments on the RMC was studied. Cake morphologies of 21 bacterial strains obtained after freeze-drying with one standard protocol could be classified visually into four major types: no collapse, porous, partial collapse, and collapse. The more pronounced the collapse, the higher residual moisture content of the freeze-dried product, ranging from 1.53 % for non-collapsed products to 3.62 % for collapsed products. The most important cause of collapse was the mass of the inserted cotton plug in the ampoule. Default cotton plugs with a mass between 21 and 30 mg inside the ampoule did not affect the viability of freeze-dried Aliivibrio fischeri LMG 4414(T) compared to ampoules without cotton plugs. Cotton plugs with a mass higher than 65 mg inside the ampoule induced a full collapsed product with rubbery look (melt-back) and decreasing viability during storage. Heat radiation effects in the freeze-drying chamber and post freeze-drying treatments such as exposure time to air after freeze-drying and manifold drying time prior to heat sealing of ampoules influenced the RMC of freeze-dried products. To produce uniform batches of freeze-dried bacterial strains with intact cake structures and highest viabilities, inserted cotton plugs should not exceed 21 mg per ampoule. Furthermore, heat radiation effects should be calculated in the design of the primary drying phase and manifold drying time before heat sealing should be determined as a function of exposure time to air.

Secado por aspersión de citrato de calcio y magnesio a partir de dolomita / Spray drying of calcium and magnesium citrate from dolomite

Introducción: el calcio es un nutriente esencial que se requiere en cantidades sustanciales, pero muchas dietas son deficientes de calcio, lo que hace necesario suplementar el mismo. Por otro lado, el secado por aspersión es una tecnología importante usada en la industria farmacéutica. Con este proceso de secado se obtiene un producto final que obedece a los estándares de calidad necesarios. Objetivo: este estudio se realizó para evaluar el secado por aspersión del citrato de calcio y magnesio y su comparación con el método tradicional de secado. Métodos: se obtuvieron lotes de citrato de calcio y magnesio a escala de banco a partir de dolomita y se suspendieron en agua en una proporción 1:10 (masa/volumen). Posteriormente fueron secados mediante secado por aspersión. Se evaluaron los lotes obtenidos mediante métodos de análisis químicos y tecnológicos. Resultados: los resultados mostraron que el contenido de calcio, magnesio, ácido cítrico y cenizas totales eran similares independiente del método de secado empleado. El contenido de humedad residual en las muestras secadas por aspersión fue superior al de las muestras secadas por el método tradicional. No obstante, los resultados obtenidos en ambos casos estaban por debajo del límite máximo permisible. Las propiedades físicas de las muestras para cada método de secado estudiado fueron similares, excepto para la densidad, dónde se observó que las muestras secadas por aspersión tienen valores de densidad menores que las muestras secadas por el método tradicional. Conclusiones: los resultados demuestran que las condiciones de secado por aspersión estudiadas son adecuadas para el secado del citrato de calcio y magnesio obtenido a partir de dolomita(AU)

Introduction: calcium is an essential nutrient required in substantial amounts, but many diets are deficient in calcium making supplementation necessary or desirable. On the other hand, spray drying is an important technology used in the pharmaceutical industry. In this process the end-product must comply with precise quality standards. Objective: To evaluate the spray drying of calcium and magnesium citrate and to make comparison with the traditional method of drying. Methods: calcium and magnesium citrate salt was obtained at bench scale from dolomite and suspended in water in a proportion 1:10 (w/v) and spray-dried. The final batches were evaluated by chemical and technological analysis methods Results: the results showed that calcium, magnesium, citric acid and total ash content have similar concentrations regardless of the used drying method. Residual moisture content of the dried product by spray drying method was higher than that of the dried sample by traditional method. Nevertheless, all the results were below the maximum allowable limit. The physical properties of the samples for each drying method were similar except for density because the spray-dried samples showed values lower than those of traditionally dried samples. Conclusions: the results indicate that the tested spray drying conditions are suitable for drying of calcium and magnesium citrate from dolomite(AU)

Secado por aspersión de citrato de calcio y magnesio a partir de dolomita / Spray drying of calcium and magnesium citrate from dolomite

Introduction: calcium is an essential nutrient required in substantial amounts, but many diets are deficient in calcium making supplementation necessary or desirable. On the other hand, spray drying is an important technology used in the pharmaceutical industry. In this process the end-product must comply with precise quality standards. Objective: To evaluate the spray drying of calcium and magnesium citrate and to make comparison with the traditional method of drying. Methods: calcium and magnesium citrate salt was obtained at bench scale from dolomite and suspended in water in a proportion 1:10 (w/v) and spray-dried. The final batches were evaluated by chemical and technological analysis methods Results: the results showed that calcium, magnesium, citric acid and total ash content have similar concentrations regardless of the used drying method. Residual moisture content of the dried product by spray drying method was higher than that of the dried sample by traditional method. Nevertheless, all the results were below the maximum allowable limit. The physical properties of the samples for each drying method were similar except for density because the spray-dried samples showed values lower than those of traditionally dried samples(AU)

Introducción: el calcio es un nutriente esencial que se requiere en cantidades sustanciales, pero muchas dietas son deficientes de calcio, lo que hace necesario suplementar el mismo. Por otro lado, el secado por aspersión es una tecnología importante usada en la industria farmacéutica. Con este proceso de secado se obtiene un producto final que obedece a los estándares de calidad necesarios. Objetivo: este estudio se realizó para evaluar el secado por aspersión del citrato de calcio y magnesio y su comparación con el método tradicional de secado. Métodos: se obtuvieron lotes de citrato de calcio y magnesio a escala de banco a partir de dolomita y se suspendieron en agua en una proporción 1:10 (masa/volumen). Posteriormente fueron secados mediante secado por aspersión. Se evaluaron los lotes obtenidos mediante métodos de análisis químicos y tecnológicos. Resultados: los resultados mostraron que el contenido de calcio, magnesio, ácido cítrico y cenizas totales eran similares independiente del método de secado empleado. El contenido de humedad residual en las muestras secadas por aspersión fue superior al de las muestras secadas por el método tradicional. No obstante, los resultados obtenidos en ambos casos estaban por debajo del límite máximo permisible. Las propiedades físicas de las muestras para cada método de secado estudiado fueron similares, excepto para la densidad, dónde se observó que las muestras secadas por aspersión tienen valores de densidad menores que las muestras secadas por el método tradicional. Conclusiones: los resultados demuestran que las condiciones de secado por aspersión estudiadas son adecuadas para el secado del citrato de calcio y magnesio obtenido a partir de dolomita(AU)