Freeze drying aerosols

Maa et al. [3.84] used spray drying and spray freeze-drying (see Chapter 5, [5.13, 5.14]) to produce protein powders for inhalation from deoxyribonuclease (rhDNase) and anti-IgE monoclonal antibody (anti-IgE Mab) with lactose as carrier. Spray freezedrying produced light and porous protein particles with superior aerosol performance. 

Although excipients are the non-active ingredients, they are indispensable for the successful production of acceptable solid dosage forms. The important roles played by excipients in tablets and capsules, freeze-dried, and spray-dried powders, as well as powder aerosol formulations, were discussed. Some recent applications of excipients in controlled, release formulations for biologicals were also highlighted. Finally, incompatibility problems attributable to excipients were considered with an emphasis on the indirect role of excipients through moisture distribution. 

Nanoparticles of all descriptions can be used not only as suspensions but also as freeze-dried powders for reconstitution, incorporated into liposomes, as aerosols, in gels and microspheres (e.g., gelatin), adsorbed onto microparticles, dispersed in soft-gelatin capsules [e.g., in polyoxyethylene glycols (PEGs)], or as mini-depot tablets. 

When aerosolized, VACV has been demonstrated much less persistent. Aerosolized VACV was almost completely inactivated within 6 h at 31-33°C and 80% humidity [39], As the temperature decreases to 10°C-11°C and humidity is decreased to 20%, the survival rate of virions increases after 24 h, only 33% of the vims was reported inactivated [39], When frozen in buffer at -20°C, a titer reduction of only 3 log-steps is reported within 15 years [91], Freeze-dried material persisted at 45°C for a period of 6 years with little signs of inactivation [28],... 

Urine (Matusiewicz and Barnes, 1985) - NIOSH-NBS freeze dried urine is reconstituted in water. 50 nL samples are determined. Instrumentation Plasma-Therm model 5000D ICP-AES spectrometer. Instrumentation Laboratory FASTAC II pneumatic nebulizer/aerosol delivery system to deliver sample to a model IL655 furnace for graphite furnace vaporization at 2500°C. Argon plasma, 40.68 MHz, A = 231.60 nm, pyrolytically coated graphite tube with platform. Detection limit 0.9 hqIL (45 pg Ni) by peak area, 12 /peak height. Urine reference material found 1.05 mg/L (RSD 2.1%), expected 1.01 0.11 mg/L. 

In the analysis of a marine aerosol, the flrst step is to divide it into a water-soluble fraction which we call salt and an insoluble fraction referred to as dust. This is achieved by washing the collecting nylon sail or filter with distilled water (12). The dust is removed from the suspension by centrifugation and filtration. It is dried at 110°C and weighed. The salt is either isolated from an aliquot of the supemate by freeze drying, or the dissolved ions of interest are determined directly. The amount of salt in each sample is determined by weighing or by summing the major constituents. 

Spray-freeze-drying Good particle size control spherical-shaped particles high yield good aerosol properties Poor density control... 

Thermal inkjet spray freeze-drying was used to produce inhalable particles of terbutaline sulfate (37). Scanning electron micrograph images proved that the particles are spherical, highly porous and suitable for aerosolization from a capsule-based dry-powder device. There is no need for additional experiments. 

It is important to appreciate that products intended for freeze-drying will have been formulated with additives designed to stabilise the active component to prevent dehydration damage (see section 10.5). Consequently such formulations are likely to be more resistant to decay when disseminated as an aerosol during filling, freeze-drying or oversealing. 

Comparison of protection during aerosolation or freeze-drying... 

H Seager, CB Taskis, M Syrop, TJ Lee. Freeze drying parenterals eontaining organic solvent - Part 1. Manuf Chem Aerosol News 49(ll) 43-44, 47-48, 1978. 

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