Spray Freeze-Drying for inhalation application: Process and Formulation Variables

AbstractBotulinum neurotoxin (BoNT), produced by Clostridium botulinum, is generally known to be the most poisonous of all biological toxins. In this study, we evaluate the protection conferred by intratracheal (i.t.) inoculation immunization with recombinant Hc subunit (AHc) vaccines against aerosolized BoNT/A intoxication. Three AHc vaccine formulations, i.e., conventional liquid, dry powder produced by spray freeze drying, and AHc dry powder reconstituted in water are prepared, and mice are immunized via i.t. inoculation or subcutaneous (s.c.) injection. Compared with s.c.-AHc-immunized mice, i.t.-AHc-immunized mice exhibit a slightly stronger protection against a challenge with 30,000× LD50 aerosolized BoNT/A. Of note, only i.t.-AHc induces a significantly higher level of toxin-neutralizing mucosal secretory IgA (SIgA) production in the bronchoalveolar lavage of mice. In conclusion, our study demonstrates that the immune protection conferred by the three formulations of AHc is comparable, while i.t. immunization of AHc is superior to s.c. immunization against aerosolized BoNT/A intoxication.

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A comparative study of encapsulation of carotenoid enriched-flaxseed oil and flaxseed oil by spray freeze-drying and spray drying techniques

LWT ◽

10.1016/j.lwt.2021.111153 ◽

2021 ◽

Vol 143 ◽

pp. 111153

Author(s):

Aysel Elik ◽

Derya Koçak Yanık ◽

Fahrettin Göğüş

Keyword(s):

Comparative Study ◽

Spray Drying ◽

Freeze Drying ◽

Flaxseed Oil ◽

Drying Techniques ◽

Spray Freeze Drying

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Post-Processing Techniques for the Improvement of Liposome Stability

Pharmaceutics ◽

10.3390/pharmaceutics13071023 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1023

Author(s):

Ji Young Yu ◽

Piyanan Chuesiang ◽

Gye Hwa Shin ◽

Hyun Jin Park

Keyword(s):

Freeze Drying ◽

Protective Agent ◽

Post Processing ◽

Additional Process ◽

Spray Freeze Drying ◽

The Stability ◽

Processing Techniques ◽

The Impact ◽

Self Aggregation ◽

Liposome Stability

Liposomes have been utilized as a drug delivery system to increase the bioavailability of drugs and to control the rate of drug release at the target site of action. However, the occurrence of self-aggregation, coalescence, flocculation and the precipitation of aqueous liposomes during formulation or storage can cause degradation of the vesicle structure, leading to the decomposition of liposomes. To increase the stability of liposomes, post-processing techniques have been applied as an additional process to liposomes after formulation to remove water and generate dry liposome particles with a higher stability and greater accessibility for drug administration in comparison with aqueous liposomes. This review covers the effect of these techniques including freeze drying, spray drying and spray freeze drying on the stability, physicochemical properties and drug encapsulation efficiency of dry liposomes. The parameters affecting the properties of liposomes during the drying process are also highlighted in this review. In addition, the impact of using a protective agent to overcome such limitations of each process is thoroughly discussed through various studies.

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