News

Bulk Dynamic Spray Freeze-Drying Part 1: Modeling of Droplet Cooling and Phase Change

Israel B. Sebastião, Bakul Bhatnagar, Serguei Tchessalov, Satoshi Ohtake, Matthias Plitzko, Bernhard Luy, Alina Alexeenko

Abstract

In spray freeze-drying (SFD), the solution is typically dispersed into a gaseous cold environment producing frozen microparticles that are subsequently dried via sublimation. This technology can potentially manufacture bulk lyophilized drugs at higher rates compared with conventional freeze-drying in trays and vials because small frozen particles provide larger surface area available for sublimation. Although drying in SFD still has to meet the material collapse temperature requirements, the final characteristics of the respective products are mainly controlled by the spray-freezing dynamics. In this context, the main goal of this work is to present a single droplet spray-freezing model and validate it with previously published simulations and experimental data. For the investigated conditions, the droplet temperature evolutions predicted by the model agree with experiments within an error of ±10%. The proposed engineering-level modeling framework is intended to assist future development of efficient SFD processes and support scale up from laboratory to commercial scale equipment.

Keywords

spray freeze-drying, sucrose, quality by design (QBD), lyophilization, freeze-drying, mathematical model(s)

Micro and nano encapsulation, retention and controlled release of flavor and aroma compounds: A critical review

Md. Saifullah, Mohammad Rezaul Islam Shishir, Rayhana Ferdowsi, Md Ramim Tanver Rahman, Quan Van Vuong

Abstract

Background

Encapsulation of flavor and aroma in an appropriate form is an important concern for a long time. Encapsulation is the most successful way not only to preserve or mask flavor and aroma compounds but also to enhance their thermal and oxidative stability, overcome the limitations of high volatility, to control the fast release and improve the poor bioavailability, as well as to increase their application in food systems.
Scope and approach

This review focuses on the recent advances in micro and nano-encapsulation of flavor and aroma compounds. We comprehensively highlight the suitability of micro and nano-encapsulation approaches for the retention of flavor and aroma including emerging techniques, new formulations and novel encapsulate systems, to illustrate the flavor release mechanisms, and depict the industrial applications of encapsulated flavor and aroma compounds.
Key findings and conclusions

Nano-encapsulation has attracted more attention compared to microencapsulation; showing better encapsulation efficiency, enhanced stability of capsule, and more control on flavor release. Recently, spray chilling and spray freeze drying as an alternative to spray drying, can overcome the thermal loss of flavor, promising for the microencapsulation of heat sensitive compounds. In contrast, electro-spraying and electro-spinning in combination with the emulsion or coaxial approach are novel and promising for the nano-encapsulation of flavor and aroma compounds. The combination of carrier materials, e.g. polysaccharide with protein can improve the encapsulation efficiency and capsule functionality. However, application of micro and nano-encapsulates into different food and gastrointestinal systems needs to be explored in order to expose their release mechanisms and application efficiency.

Keywords

Flavor, Aroma, Microencapsulation, Nano-encapsulation, Stability, Industrial application, Food

Porous and highly dispersible voriconazole dry powders produced by spray freeze drying for pulmonary delivery with efficient lung deposition

Liao Q, Yip L, Chow MYT, Chow SF, Chan HK, Kwok PCL, Lam JKW

Abstract

Systemic administration of antifungal agents for the treatment of pulmonary aspergillosis is limited by the poor lung deposition and severe adverse effects. In contrast, pulmonary delivery allows a higher amount of drug to be delivered directly to the infection site and therefore a lower dose is required. This study aimed to develop porous and inhalable voriconazole dry powder with good lung deposition by spray freeze drying (SFD), using tert-butyl alcohol (TBA) as a co-solvent. A three-factor two-level full factorial design approach was used to investigate the effect of total solute concentration, drug content and co-solvent composition on the aerosol performance of the SFD powder. In general, the SFD voriconazole powder exhibited porous and spherical structure, and displayed crystalline characteristics. The analysis of factorial design indicated that voriconazole content was the most significant variable that could influence the aerosol performance of the SFD powders. The formulations that contained a high voriconazole content (40% w/w) and high TBA concentration in the feed solution (70% v/v) displayed the highest fine particle fraction of over 40% in the Next Generation Impactor study in which the powder was dispersed with a Breezhaler® at 100 L/min. In addition, the fine particle dose of the SFD powder showed a faster dissolution rate when compared to the unformulated voriconazole. Intratracheal administration of SFD voriconazole powder to mice resulted in a substantially higher drug concentration in the lungs when comparing to the group that received an equivalent dose of liquid voriconazole formulation intravenously, while a clinically relevant plasma drug concentration was maintained for at least two hours. Overall, an inhalable voriconazole dry powder formulation exhibiting good aerosol property and lung deposition was developed with clinical translation potential.

Keywords

Antifungal; Factorial design; Next generation impactor; Pulmonary delivery; Spray freeze drying; Voriconazole

Fabrication of homogenous pellets by freeze granulation of optimized TiO₂-Y₂O₃ suspensions

F. La Lumia, L. Ramond, C. Pagnoux, G. Bernard-Granger

Abstract

MOX fuels are used in nuclear reactors. To ensure the manufacture of MOX, wet processes are investigated. Freeze granulation of water-based powder suspension seems a promising way to yield homogenous and easy-to-press UO₂-PuO₂ granules. These granules are expected to form dense and homogenous pellets by uniaxial pressing. Granules and pellet properties are affected by suspension formulation and atomization conditions. Therefore, these conditions must be studied and optimized to produce granules with good processability and thus MOX pellets with compliant density, homogeneity and absence of defects. In this scope, key properties of water-based suspensions of UO₂ and PuO₂ surrogate powders, TiO₂ and Y₂O₃ respectively, were firstly studied to assess their suitability for the freeze granulation process. These properties were compared to those of UO₂ and PuO₂ suspensions to verify and confirm the correctness in the choice of surrogate powders. Then, the freeze granulation process itself was investigated focusing on TiO₂-Y₂O₃ suspensions.

Keywords

Suspension, Granulation, Freeze drying, UO₂, PuO₂

Supporting data and methods for the multi-scale modelling of freeze-drying of microparticles in packed-beds

Luigi C. Capozzi, Antonello A. Barresi, Roberto Pisano

Abstract

A multi-scale approach can be used to simulate the drying behavior of microparticles in packed-bed. Data outcomes from discrete element method (DEM) and computational fluid dynamics (CFD) simulations can be used to estimate some relevant product characteristics, such as the porosity, tortuosity, voids in the bed and permeability which are required by the multi scale model. Data from DEM simulations are presented, with a particular focus on the influence of the model parameters, packing characteristics and inhomogeneities (wall effect and particles segregation); computational costs and scala bility are also considered. Data on the properties of packings as modeled at the macroscale are presented with regard to the thermal conductivity of gases in the Knudsen regime and effective properties of packed-beds modeled as a pseudo-homogeneous medium. A mathematical model of the freeze-drying of single microparticles and its outcomes are first presented. Data outcomes from the mathematical model at the macroscale concerning the drying behavior of microparticles in a tray and in a vial are then presented and can be used for process design. Some further data, with detailed interpretation and discussion of the presented data, can be found in the related research data article, “A multi-scale computational framework for modelling the freeze-drying of microparticles in packed-beds” (Capozzi et al., 2019).

Keywords

Freeze-drying, Packed-bed, Lyophilization, DEM, CFD, Spray-freeze drying

Cryogenic Fabrication of Dry Powders to Enhance the Solubility of a Promising Anticancer Drug, SHetA2, for Oral Administration

Ibrahim M, Hatipoglu MK, Garcia-Contreras L

Abstract

SHetA2 is a novel anticancer drug with poor aqueous solubility. In formal toxicological studies, Kolliphor HS 15 was used as a solubilizing agent to increase the oral bioavailability of SHetA2. The purpose of this study was to formulate SHetA2 and Kolliphor HS 15 as solid powders to facilitate their filling in hard gelatin capsules for clinical trials. Two manufacturing processes, ultra-rapid freeze-drying (URFD) and spray freeze drying (SFD), were employed to fabricate solid powders of SHetA2-Kolliphor HS 15 and trehalose. The morphology, size, flowability, and compressibility of URFD-SHetA2 and SFD-SHetA2 powders were characterized. The crystallinity and apparent maximum solubility of SHetA2 in both powders were also determined. SFD-SHetA2 powders were spherical in shape, small, and with a wide size distribution while the URFD-SHetA2 powders were irregularly shaped and big but with a narrower distribution. DSC and XRD analyses indicated that SHetA2 was mostly amorphous in both powders. The flow of both powders was categorized as “good” (angle of repose < 35°). The uniformity of drug content in URFD-SHetA2 powders was more variable than that in SFD-SHetA2 powders. The solubility profile of SHetA2 in both powders SGF exhibited a transient supersaturation “spring effect” due to the drug’s amorphousness followed by extended supersaturation “parachute effect” at approximately 6 μg/ml for both powders compared to 0.02 ± 0.01 μg/ml for unprocessed drug. In conclusion, both URFD and SFD formed solid SHetA2 Kolliphor powders that are possible formulation candidates to be filled in hard gelatin capsules for clinical trials.

Keywords

Kolliphor HS 15; SHetA2; spray freeze drying; spring and parachute effect; ultra-rapid freeze drying

Influence of Nanoparticle Pretreatment on the Thermal, Rheological and Mechanical Properties of PLA-PBSA Nanocomposites Incorporating Cellulose Nanocrystals or Montmorillonite

Wissam Abdallah, Amin Mirzadeh, Victor Tan, Musa R. Kamal

Abstract

Nanoparticles based on cellulose nanocrystals (CNC) and montmorillonite clay (MMT) were prepared using spray freeze-drying. The nanoparticles were then used as reinforcement to prepare nanocomposites with poly(lactic acid) (PLA) as the polymer matrix. The effect of spray freeze-dried CNC (SFD-CNC) and spray freeze-dried MMT (SFD-MMT) on the rheological and mechanical properties of PLA and its blends with poly(butylene succinate)-co-adipate) were investigated. An epoxy chain extender was used during preparation of the blends and nanocomposites to enhance the mechanical properties of the products. Different methods such as scanning electron microscopy, X-ray diffraction and adsorption/desorption analyses were used to characterize the prepared nanoparticles and their localization in the blends. Dynamic oscillatory shear behavior, elongational viscosity and mechanical characteristics of the nanocomposites of PLA and the blends were evaluated. The results obtained for nanocomposites filled with unmodified SFD-MMT were compared with those obtained when the filler was a commercial organically modified montmorillonite nanoclay (methyl-tallow-bis(2-hydroxyeethyl) quaternary ammonium chloride) (C30B), which was not spray freeze-dried.

Spray Freeze-Drying Technology: Enabling Flexibility of Supply Chain and Drug-Product Presentation for Biologics

Deirdre Lowe, Mehak Mehta, Geetha Govindan, Kapil Gupta

Abstract

Biopharmaceutical drug substances (DSs) and drug products (DPs) commonly are stored frozen or refrigerated to maintain stability through long-term storage, handling, and transportation (1). Temperature excursions during storage and transport can affect product quality adversely by compromising the safety and efficacy of these molecules. Thus, cold-chain management throughout the shelf life of these products is a critical component in the supply chain strategy for them.

Pharmaceutical Freeze Drying Technology 2018

Overview

Although an old process, pharmaceutical freeze drying is ever evolving with new trends and approaches being used for pharmaceutical formulation. In it’s 6th year, the conference will cover the most recent advances in Freeze drying technology and discuss the latest ideas in the industry. It is the perfect platform to strengthen knowledge in key principles such as PAT and QbD, whilst staying at the forefront of technological breakthroughs to adapt to growing manufacturing demands.

Gathering a room of Senior Scientists and Heads of Pharmaceutical Engineering, the 6th annual show provides an ideal forum to discuss the latest advancements in pharmaceutical lyophilisation, welcoming regulatory guidance from the NIBSC-MHRA and expertise from the likes of Sanofi, Boehringer Ingelheim, Janssen, GSK and more!

Spray-freeze-drying: A novel process for the drying of foods and bioproducts

S. Padma Ishwarya, C. Anandharamakrishnan, Andrew G.F. Stapley

Abstract

Spray-freeze-drying (SFD) is an unconventional freeze drying technique that produces uniquely powdered products whilst still including the benefits of conventionally freeze dried products. SFD has potential applications in high value products due to its edge over other drying techniques in terms of product structure, quality, and the retention of volatiles and bioactive compounds. In cases where other drying techniques cannot provide these product attributes, SFD stands out despite the costs and complexities involved. This paper outlines the principles, methods, significant process parameters, particle morphology and quality aspects of SFD. Recent developments in this technique are reviewed including ultrasonic spray-freeze-drying, the application of computational fluid dynamics and mathematical modelling, and the incorporation of new technologies to improve product quality. In addition, the advantages, limitations and future scope for research in the field of SFD are discussed.