Hard Capsules for Dry-Powder Inhalers: Performance on Puncturing

The study presented describes the behavior of various dry-powder inhaler (DPI) hard capsules under puncture, at different relative humidities (RH). Our objective was to study the puncturing force and holes morphology of gelatin, gelatin/PEG and hypromellose hard capsules when equilibrated at low RH and subjected to puncturing with a pin from commercial DPI device.