Stable high surface area lactate dehydrogenase particles produced by spray freezing into liquid nitrogen

Formation of Stable Submicron Protein Particles by Thin Film Freezing

“…The 10 to 100 μm diameter atomized droplets travel through the cryogenic gas, where they may begin to freeze (30), and freeze completely at a cooling rate of ∼10 6 K/s after contacting the liquid cryogen. By systematically studying the effects of the separate spraying, freezing and drying steps in SFD, the large gas-liquid interface in the spraying step was shown to be the primary cause of protein aggregation for recombinant human interferon γ (rhIFN-γ) (19), lysozyme (31), and more recently lactate dehydrogenase (LDH) (32). The interfacially active protein adsorbs at this interface and subsequently unfolds and forms aggregates (1,11,18,19,21,33).…”

“…This modification resulted in less protein adsorption, denaturation and aggregation, and consequently, higher enzymatic activities than in SFD (31,32,34,35). The jet dimensions in SFL led to a cooling rate of ∼10 3 K/s as a result of the Leidenfrost effect, in which evaporation of liquid nitrogen produced an insulating layer (32,36,37).…”

Templated Open Flocs of Nanorods for Enhanced Pulmonary Delivery with Pressurized Metered Dose Inhalers

“…This size range may be produced by milling (11,17), spray drying (3,(19)(20)(21), and spray freeze-drying (SFD) (22,23). Two recent particle engineering processes, spray freezing into liquids (SFL) (24)(25)(26)(27)(28), and thin film freezing (TFF) (29), were shown to produce high surface area, stable rodlike particles with 50-100 nm diameters and high aspect ratios, despite slower cooling rates than in SFD. The stability of lactate dehydrogenase, based on enzymatic activity, was increased in these processes relative to SFD, as a result of a reduction in the surface area of (26,29) the destabilizing gas-liquid interface (26,30).…”

“…Two recent particle engineering processes, spray freezing into liquids (SFL) (24)(25)(26)(27)(28), and thin film freezing (TFF) (29), were shown to produce high surface area, stable rodlike particles with 50-100 nm diameters and high aspect ratios, despite slower cooling rates than in SFD. The stability of lactate dehydrogenase, based on enzymatic activity, was increased in these processes relative to SFD, as a result of a reduction in the surface area of (26,29) the destabilizing gas-liquid interface (26,30). Limited process yields, in terms of weight of protein, for spray drying (50-70%) (22,31) and SFD (∼80%) (22,31,32) are a major concern for highly valuable proteins.…”

Precipitation Technologies for Nanoparticle Production

“…Relative to top-down approaches (milling and homogenization processes), precipitation technologies are typically more controlled, in terms of consistently producing particles with similar morphologies, and offer the ability to achieve higher drug loadings (Matteucci et al 2006Overhoff et al 2007a, b ;Engstrom et al 2007Engstrom et al , 2008Rasenack and Muller 2002 ;Rogers et al 2004 ;Shoyele and Cawthorne 2006 ;Vaughn et al 2005 ;Young et al 2000 ) . Precipitation processes are often easier to scale-up and require less particle handling than milling and homogenization operations, resulting in higher process yields and lower impurity risks, as well as simplifi ed cleaning and sterilization procedures (Rogers et al 2001a ) .…”