title: Protein spheres prepared by drop jet freeze drying.
abstract: In spray freeze drying (SFD) solutions are frozen by spraying into a very cold environment and subsequently dried by sublimation. In contrast to conventional freeze drying, spray freeze drying has the possibility to produce flowable lyophilizates which offers a variety of new pharmaceutical applications. Here, a drop jet nozzle is proposed as liquid dispenser that is able to produce droplets with a very narrow size distribution compared to standard methods. The drop jet nozzle is mounted in a spray tower designed to prevent direct contact of the product with the freezing medium. Various formulations have been tested containing lysozyme as model protein and stabilizers such as bovine serum albumin, polyvinylpyrrolidone or dextran in various concentrations and mannitol. Excellent free flowing and nearly monodispersed, porous particles are produced where particle properties can be controlled by formulation and process conditions. The particle diameter varied between 231 ± 3 μm and 310 ± 10 μm depending on the formulation composition. The lysozyme activity was >94 ± 5% for all formulations exhibiting a full preservation of enzyme activity. This new method is very promising for the production of nearly monodisperse particulate lyophilizates in various therapeutic applications.
authors.affiliation: Laboratory of Pharmaceutical Technology and Biopharmaceutics, University of Bonn, Gerhard-Domagk-Str. 3, 53121 Bonn, Germany.
authors.forename: Sören N
authors.initials: SN
authors.lastname: Eggerstedt
authors.forename: Mathias
authors.initials: M
authors.lastname: Dietzel
authors.forename: Martin
authors.initials: M
authors.lastname: Sommerfeld
authors.forename: Richard
authors.initials: R
authors.lastname: Süverkrüp
authors.forename: Alf
authors.initials: A
authors.lastname: Lamprecht
mesh_terms: D004339:Drug Compounding / Q000379:methods*; D005612:Freeze Drying / Q000379:methods; D008353:Mannitol / Q000737:chemistry; D009113:Muramidase / Q000737:chemistry*; D010316:Particle Size; D011134:Polysaccharides / Q000737:chemistry; D016062:Porosity; D011205:Povidone / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013499:Surface Properties; D014783:Viscosity
chemical_list: D011134:Polysaccharides; D012710:Serum Albumin, Bovine; D008353:Mannitol; C008315:maltodextrin; D009113:Muramidase; D011205:Povidone