Pulmonary drug delivery microparticles

A composition based on diketopiperazine derivatives (3,6-bis (N-fumaryl-N-(n-butyl) amino-2, 5-diketopiperazine) has been investigated as a pulmonary drug delivery system, termed Technospheres (Pharmaceutical Discovery Corp., Elmsford, NY) (Pohl et al. 2000 Steiner et al. 2002). The diketopiperazine derivatives self-assemble into microparticles at low pH with a mean diameter of approximately 2 pm. During self-assembly, diketopiperazine derivatives microencapsulate peptides present in the solution. Insulin incorporated in diketopiperazine derivatives (TI) was administered to five healthy humans by the use of a capsule-based inhaler with a passive powder deagglomeration mechanism. Relative and absolute bioavailability of TI in the first 3 hours (0-180 min) were 26 12% and 15 5%, and for 6 hours (0-360 min) 16 8% and 16 6%, respectively (Steiner et al. 2002). The time to peak action for glucose infusion rates was shorter with both IV (14 6 min) injection and inhalation (39 36 min), as compared to SC administration (163 25 min). This rapid absorption of insulin would be beneficial for diabetic patients who need to rapidly affect their glucose levels. 

Yang Y, Bajaj N, Xu P, Ohn K, Tsifansky MD, Yeo Y. Development of highly porous large PLGA microparticles for pulmonary drug delivery. Biomaterials 2009 30(10) 1947-53. 

A.L Feng, M.A. Boraey, M.A. Gwin, P.R. Finlay, RJ. Kuehl, R. Vehring, Mechanistic models facilitate efficient development of leucine containing microparticles for pulmonary drug delivery. International Journal of Pharmaceutics, 409,156-163, 2011. 

SLM combines the advantages of different drug delivery systems such as polymeric microparticles, fat emulsions, and liposome. In this respect, they have been successfully proposed for the delivery of a variety of drugs including antibiotics, anti-inflammatory compounds, vaccines, and adjuvant. Among the hpids, phospholipids, triacyl glycerols, waxes, fatty acids, or their mixtures can be used. SLM can be administered by subcutaneous, oral, intramuscular, topical, or pulmonary ways. 

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