title: That's cool!--Nebulization of thermolabile proteins with a cooled vibrating mesh nebulizer.
abstract: Despite contrary reports, heating inside the medication reservoir was observed for several vibrating mesh nebulizers, which may be detrimental when nebulizing biopharmaceuticals. In this study we evaluated different strategies to reduce reservoir heating during nebulization with a PARI eFlow® regarding cooling efficiency, impact on nebulizer performance and on protein stability after nebulization. Passive cooling was achieved by solution pre-cooling, overcharging of the reservoir with 1 mL additional solution or intermittent nebulization. Active cooling was realized with a micro Peltier element attached to the nebulizer reservoir. Passive cooling was most effective when the reservoir was overcharged with pre-cooled solution reducing the average reservoir temperature (TRES AVG) by 8.4°C. Active cooling enabled nebulization at a constant reservoir temperature (TRES) as low as 15°C. TRES manipulation had a linear impact on nebulizer performance. While the output rate decreased with decreasing TRES, the inhalable fraction increased resulting in an inhalable aerosol rate constant over a large TRES range. The effect on protein stability depended on the susceptibility to thermal stress and was predicted by Tm values. For lactic dehydrogenase and SM101, both exhibiting a Tm below 60°C, cooling was protective in increasing the residual activity and reducing protein aggregation. A more thermostable IgG1 did not benefit from cooled nebulization. Nebulizer cooling is a prerequisite to retain the activity and stability of thermolabile proteins during vibrating mesh nebulization. It is best achieved by micro Peltier based active cooling or by simple passive cooling strategies.
authors.affiliation: Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, Ludwig Maximilian University Munich, Munich, Germany. Electronic address: sebastian.hertel@cup.uni-muenchen.de.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hertel
authors.affiliation: SuppreMol GmbH, Martinsried, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pohl
authors.affiliation: Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, Ludwig Maximilian University Munich, Munich, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Friess
authors.affiliation: Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, Ludwig Maximilian University Munich, Munich, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Winter
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols; D000818:Animals; D002626:Chemistry, Pharmaceutical; D003080:Cold Temperature; D016503:Drug Delivery Systems / Q000295:instrumentation*; D004867:Equipment Design; D058851:GPI-Linked Proteins / Q000008:administration & dosage / Q000737:chemistry; D006801:Humans; D045022:Lactate Dehydrogenases / Q000008:administration & dosage* / Q000737:chemistry*; D009330:Nebulizers and Vaporizers; D011487:Protein Conformation; D011489:Protein Denaturation; D055550:Protein Stability; D011817:Rabbits; D017452:Receptors, IgG / Q000008:administration & dosage* / Q000737:chemistry*; D013678:Technology, Pharmaceutical / Q000379:methods; D013997:Time Factors; D014732:Vibration
chemical_list: D000336:Aerosols; C428200:FCGR3B protein, human; D058851:GPI-Linked Proteins; D017452:Receptors, IgG; D045022:Lactate Dehydrogenases
keywords: Active cooling; FcγRIIB; IgG; LDH; Nebulizer performance; PARI eFlow®; Protein stability; Vibrating mesh nebulization