EP1501479A1 — Capsules for dry powder inhalers and methods of making and using same

USPTO Abstract

Pulmonary delivery of dry powder formulations by aerosol inhalation has received much attention as an attractive alternative to intravenous, intramuscular, and subcutaneous injection, since this approach eliminates the necessity for injection syringes and needles. The present invention provides dry powder filled cellulose-based capsules having particular utility for use with dry powder inhalers. Such capsules not only readily coordinate with conventional DPIs but also coordinate with conventional powder filling technologies, thereby saving time, labor and cost. The invention further provides a novel procedure for determining, ab initio, appropriate and optimal conditions for preparing such powder filled capsules. Specifically, when packaging dry powder formulations for long-term storage, it is important to ensure that the water content of the powder does not exceed the critical moisture point, that point at which the powder loses physical and chemical stability. The present invention describes means for predicting equilibrium moisture contents, which in turn can be used to establish suitable capsule preparation and filling protocols.