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24 / June 2020 powderbulk.com increases surface area, improving bioavailability. The latter application tends to interest R&D personnel in pharmaceutical manufacturing for testing different form factors of both active pharmaceutical ingredients and excipients during formulation. Generally, both of these require a reduction in air pressure. PBE References 1. McInnes, GT, et al. "Effect of micronization on the bioavail- ability and pharmacologic activity of spironolactone." Jour- nal of Clinical Pharmacology. 1982 Aug-Sep; 22(8-9):410-7. 2. Chaumeil, JC. "Micronization: a method of improving the bioavailability of poorly soluble drugs." Methods Find Exp Clin Pharmacol. 1998; 20(3): 211-5. 3. Loh, ZH, Samanta, AK, Heng PWS. "Overview of milling techniques for improving the solubility of poorly water- soluble drugs." Asian Journal of Pharmaceutical Sciences. 2014; 10:255-74. 4. Pharmaceutical Technology editors. "Optimizing high- potency manufacturing." Pharmatech, 2011; 35 (6); accessed on line 4/1/2018. 5. Kesisoglu, F and Wu, Y. "Understanding the effect of API properties on bioavailability through absorption modeling." AAPS J. 2008 Dec; b10(4):516-525. Published online 2008 Nov 6. doi:10.1208/s12248-008-9061-4. For further reading Find more information on this topic in articles listed under "Size reduction" in Powder and Bulk Engineering's article index in the December 2019 issue or the article archive on PBE's website, www.powderbulk.com. Fred Surville (fsurville@jetpul.com, 312-502-5818) is vice president of sales and marketing for Jet Pulverizer. After receiving his BA and MS in international affairs from Florida State University, he developed his tech- nology sales and marketing skills on projects ranging from waste-to-energy, industrial zero-waste initia- tives, and data center power and cooling. He recently received his MBA from the University of Chicago Booth School of Business. Jet Pulverizer Moorestown, NJ 800-670-9695 www.jetpul.com Active ingredient bioavailability One of the most important characteristics of a jet- milled product is the huge increase in surface area. Milling a material that's 30 mesh (595 microns) down to 2,500 mesh (5 microns) results in 1,643,000 times the number of particles and a surface area that's 118 times greater. This allows for faster chemical reaction times and improved pharmaceutical ingredient performance. The increased emphasis on PSD affects high- potency manufacturing as well. For example, the increased specific surface area of finely ground active pharmaceutical ingredients results in higher bioavail- ability, making particle-size control and distribution key performance parameters. 4 In one study of micronization processes for four drug products, J.C. Chaumeil found that digestive absorption of poorly soluble drugs depended on their rate of dissolution and that decreasing the particle size using fine-grinding mills, especially jet mills, improved that rate. 2 Using Chaumeil's study as a base- line, Muller et al. reported an increase of 50 percent in the solubility of an insoluble antimicrobial compound when the particle size was reduced from 2.4 μm to 800 or 300 nm. 5 Applications beyond size reduction One of the important secondary uses for jet mills is blending powders. The operator can feed two or more streams of material into a jet mill at the same time, resulting in a homogeneous blend at the output. As stated above, pharmaceutical manufacturers have long used ball mills for blending while milling; however, co-milling in jet-milling environments has delivered consistent, homogeneous, and tighter PSD results. Finally, de-agglomeration and polishing of sharp edges is another jet mill use. The former application applies generally to spray-dried or atomized materials, which are very popular in the solid dosage manufac- turing process, usually after wet milling. This step usually creates a better-flowing product and further