title: Vial freeze-drying, part 1: new insights into heat transfer characteristics of tubing and molded vials.
abstract: In order to optimize a freeze-drying cycle, information regarding the heat transfer characteristics of the container system is imperative. Two most recently developed tubing (TopLyo™) and molded (EasyLyo™) vial designs were compared with a standard serum tubing and molded vial, a polymer vial (TopPac™), and an amber molded EasyLyo™. In addition, the impact of methodology on the determination of reliable vial heat transfer coefficient (K(v) ) data is examined in detail. All K(v) s were gravimetrically determined by sublimation tests with pure water at 50, 100, 200, and 400 mTorr. In contrast to the traditional assumption that molded vials exhibit inefficient heat transfer characteristics, these vials showed a very similar performance compared with their serum tubing counterparts in the relevant pressure range for freeze-drying. At 100 mTorr, the TopLyo™ center vials show only 4% higher K(v) values than the EasyLyo™ center vials. All glass vials outmatch the polymer vial in terms of heat transfer, up to 30% elevated heat transfer for the TopLyo™ center vials at 400 mTorr. Sublimation tests have demonstrated to be a valuable tool to investigate the heat transfer characteristics of vials, but results are dependent on methodology. New developments in molded vial manufacturing lead to improved heat transfer performance.
authors.affiliation: Division of Pharmaceutics, Freeze Drying Focus Group, University of Erlangen, 91058 Erlangen, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Hibler
authors.forename: Christophe
authors.initials: C
authors.lastname: Wagner
authors.forename: Henning
authors.initials: H
authors.lastname: Gieseler
mesh_terms: D004349:Drug Packaging; D005612:Freeze Drying / Q000379:methods*; D005898:Glass / Q000737:chemistry; D006358:Hot Temperature; D011108:Polymers / Q000737:chemistry; D014835:Volatilization
chemical_list: D011108:Polymers