Freeze drying inhalation

Preparation of cotton bract extracts. Figure 1 is a flow chart showing our procedures for preparing the various bract extracts. Dried bracts (frost killed) were hand picked just prior to harvest from cotton fields in the Lubbock, Texas area. These were stored at room temperature. Extracts were freeze-dried and stored at -4°C. For inhalation challenge by our subjects each extract was reconstituted with water or saline, as indicated, at a concentration equivalent to the standard crude extract. This Insured that for challenge purposes components were not concentrated as purification progressed. 

With respect to the shellfish meat, asthma and contact urticaria were reported in a restaurant worker from the handling of scallops (Goetz and Whisman, 2000). Inhalation of lyophilized clam in a factory producing freeze-dried clam was reported as a cause of occupational asthma (Desjardins et al, 1995). Occupational asthma has also been linked... 

Maa, Y., Nguyen, P., Sweeney, T., et al. Protein inhalation powders Spray drying vs. spray freeze drying. Pharm. Res. 16(2) 249-254, 1999. 

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. 

Maa YF, Nguyen PA, Sweeney T, Shire SJ, Hsu CC. Protein inhalation powders spray drying vs spray freeze drying. Pharm Res 1999 16 249-254. 

The delivery of freeze-dried preparations can be performed by different routes oral, nasal, anal, pulmonary, transdermal and parenteral. Of these routes, some do not require any treatment of the drug before it is administered, e.g. in the form of powders or tablets or in inhaling devices. For parenteral administration, however, whether by injection or infusion, the freeze-dried cake must be returned to a liquid state, a process referred to as reconstitution . The main vehicle will normally consist of water for injection or a solution, the concentration of which will establish isotonicity. The time required for the complete dissolution of the cake may in some cases be critical and should therefore be known. 

Wang, Y., Kho, K., Cheow, W.S., Hadinoto, K. A comparison between spray drying and spray freeze drying for dry powder inhaler formulation of drug-loaded lipid-polymer hybrid nanoparticles. Int. J. Pharm. 2012, 424 (1-2), 98-106. 

Y-F. Maa, P. Nguyen, T. Sweeney, S. Shire, and C. Hsu Protein inhalation powders spray drying vs. spray freeze drying. Pharmaceutical Research, 16, 249-255 (1999). 

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. 

Most dusts and freeze-dried material are of irregular shape and may be aggregated into loose clumps. The behaviour of such dusts when airborne depends entirely upon the mobility or settling velocity of the particles and not on their apparent microscopic size. A clump of dust may appear to be 15 pm in diameter, but if its structure is loose it may only sediment with the same speed as a 7 pm diameter sphere. When it is inhaled into the lung it will be deposited in the same manner as if it were a 7 pm sphere. 

Besides proteins, polymeric and lipid nanoparticle formulations benefit from the spray-freeze-diying process. It was possible to produce a pulmonary applicable (FPF 35—40%) spray-freeze-dried powder formulaticm COTitaining Upid or polymeric nanoparticles with excellent reconstitution characteristics [16]. The powder showed a good flowability (Q = 6-14) and superior dispersibility in air, which was proven by the low amounts of powder residue inside the capsules and the inhaler device [16]. 

Ali, M. E., Lamprecht, A. (2014). Spray freeze drying for dry powder inhalation of nanoparticles. European Journal of Pharmaceutics and Biopharmaceutics, 87, 510-517. 

Bi R, Shao W, Wang Q, Zhang N. Spray-freeze-dried dry powder inhalation of insulin-loaded liposomes for enhanced pulmonary delivery. /Drug Target. 2008 16(9) 639-48. 

The method was extended from plants to include soils and waters by Milham ef al. (1970). They point out that nitrate reductase activity in fresh plant samples often causes a rapid decline in nitrate content, so samples collected from remote sites should be frozen in dry ice. A trace of chloroform was used to protect soil and water samples before freezing. We are now more aware of the harmful effects of chloroform inhalation and suggest immediate freezing without preservative and analysis within a few days as a safer alternative - especially with student projects. 

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