Dry Powder Microparticles with Redispersible Clarithromycin Nanocrystals for High Dose Inhalation  

Anna Neustock & Regina Scherließ

Kiel University, Department of Pharmaceutics and Biopharmaceutics, Grasweg 9a, DE-24118 Kiel


Pulmonary drug delivery is an established route of administration for local and also systemic therapy. Typically, dry powder inhalers are loaded with an interactive powder blend consisting of a carrier and a small amount of high potent drugs. By preparing “Trojan” microparticles (microparticles “hiding” many nanoparticles in their shell) composed of a hollow core and a shell out of more than 70 per cent drug nanocrystals plus a small amount of matrix material, it is possible to use active ingredients with higher therapeutic doses, such as antibiotics. In this study, Clarithromycin nanocrystals for Trojan particles were prepared by media milling in an HPMC solution. The influence of different additives aiding the redispersibility of dried nanosuspensions into the primal nanocrystals was investigated. The addition of pH 5 buffer led to a Z average of 400 nm instead of > 1000 nm without further additives.

Key Message

We found an additive, that aids the disintegration of our redispersed spray-dried Trojan particles, reflected by a decreasing Z average of the released nanoparticles from >1000 nm to about 400 nm.