Freeze-Drying in Novel Container System: Characterization of Heat and Mass Transfer in Glass Syringes

Patel, Sajal M.; Pikal, Michael J.

doi:10.1002/jps.22086

Cited by 23 publications

(34 citation statements)

References 7 publications

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“…However, these results are in sharp contradiction to another report (16). In this study, glass syringes were suspended through a plexiglass holder.…”

Section: Freeze-drying In Syringescontrasting

confidence: 93%

Emerging Freeze-Drying Process Development and Scale-up Issues

Patel¹,

Pikal

2011

AAPS PharmSciTech

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Abstract. Although several guidelines do exist for freeze-drying process development and scale-up, there are still a number of issues that require additional attention. The objective of this review article is to discuss some emerging process development and scale-up issue with emphasis on effect of load condition and freeze-drying in novel container systems such as syringes, Lyoguard trays, ampoules, and 96-well plates. Understanding the heat and mass transfer under different load conditions and for freeze-drying in these novel container systems will help in developing a robust freeze-drying process which is also easier to scale-up. Further research and development needs in these emerging areas have also been addressed.

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“…However, these results are in sharp contradiction to another report (16). In this study, glass syringes were suspended through a plexiglass holder.…”

Section: Freeze-drying In Syringescontrasting

confidence: 93%

Emerging Freeze-Drying Process Development and Scale-up Issues

Patel¹,

Pikal

2011

AAPS PharmSciTech

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“…Contrary to the freeze‐drying in vials, the syringe heat transfer coefficient was pressure independent, and radiation was determined to be the dominant heat transfer mode for syringes suspended in the plexiglass holder. This is in sharp contradiction to the aforementioned assumption of Hottot et al29 Regarding the contributing mechanisms of heat transfer for the syringes in the aluminum block, gas conduction was prevalent, followed by direct conduction and radiation 30. Thus, the sublimation rate and the syringe heat transfer coefficient increased with increasing pressure.…”

Section: Relevant Container Systemscontrasting

confidence: 63%

“…For comparison, an approximately 15% higher sublimation rate was reported in literature for edge vials 12. With an increase of chamber pressure from 60 to 250 mTorr, the sublimation rate for syringes in the plexiglass holder decreased by about 28% as the driving force for sublimation decreased 30. Contrary to the freeze‐drying in vials, the syringe heat transfer coefficient was pressure independent, and radiation was determined to be the dominant heat transfer mode for syringes suspended in the plexiglass holder.…”

Section: Relevant Container Systemsmentioning

confidence: 73%

“…In a different study, the heat transfer characteristics of glass syringes were determined via sublimation tests with pure water in two different suspension systems, namely in a plexiglass holder and in an aluminum block, and compared with the glass vials by Patel et al30 The syringes at the edge of the array in the plexiglass holder showed a 70% faster sublimation rate than syringes in the center, whereas the sublimation rate of edge syringes in the aluminum block was only elevated by 4%. For comparison, an approximately 15% higher sublimation rate was reported in literature for edge vials 12.…”

Section: Relevant Container Systemsmentioning

confidence: 99%

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Heat Transfer Characteristics of Current Primary Packaging Systems for Pharmaceutical Freeze-Drying

Hibler

Gieseler

2012

Journal of Pharmaceutical Sciences

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“…], therefore more heat is transferred to the gelcast sample via gas conduction at a high pressure. The heat‐transfer coefficient K g via gas conduction is

K_{normalg} = \frac{α {normalΛ}_{0} P_{normalC}}{1 + l false(normalα Λ_{0} false/ λ_{0} false) P_{normalC}}

where Λ 0 is the free molecular heat conductivity of the gas at 0°C, λ 0 the heat conductivity of the water vapor at ambient pressure, P c the chamber pressure, l the constant “effective” distance characterizing the gap between the shelf and the sample surface, and α is a term related to the energy accommodation coefficient, α c and the absolute temperature of the gas, T ,

α = \frac{α_{C}}{2 - {normalα}_{normalC} \sqrt{\frac{273.2}{T}}}

…”

Section: Resultsmentioning

confidence: 99%

Formation Mechanism of Cracks During the Freeze Drying of Gelcast Ceramic Parts

et al. 2015

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The near‐net shaping of gelcast ceramic parts can be achieved using freeze‐drying technology. It was discovered that the cracks probably occurred inside the part during freeze drying due to the formation of liquid water. To explain the formation mechanism of cracks, the electrical resistance method was employed to measure the part's eutectic temperature which can be used to determine the freezing and melting state of the part. Affecting factors on cracking were investigated by testing the temperature and water loss of the part during the drying stage, and the cracks inside the part were detected through computed tomography (CT). It was found that when the temperature of the part was higher than the eutectic temperature, the ice crystals at the sublimation front would melt, resulting in the formation of wet green body. The cracks will occur inside the part because great capillary forces are formed in the wet green body. Cracks could be controlled through reducing heat supply by lowing shelf temperature, decreasing pressure of the drying chamber or lowering the dried layer resistance against water vapor by improving the freezing temperature or reducing the solid loading of the part.

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Freeze-Drying in Novel Container System: Characterization of Heat and Mass Transfer in Glass Syringes

Cited by 23 publications

References 7 publications

Emerging Freeze-Drying Process Development and Scale-up Issues

Emerging Freeze-Drying Process Development and Scale-up Issues

Heat Transfer Characteristics of Current Primary Packaging Systems for Pharmaceutical Freeze-Drying

Formation Mechanism of Cracks During the Freeze Drying of Gelcast Ceramic Parts

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