Purpose To investigate how excipient matrix affects punch sticking propensity of active pharmaceutical ingredients (API), with the focus on the effect of bonding interactions between API-API (F2) and API-excipient (F3). Method Sticking kinetics of direct compression formulations, consisting of 20% of celecoxib (CEL) or ibuprofen (IBN) indifferent excipient matrices, i. e., microcrystalline cellulose (Avice l PH102 and Avicel PH105 dry coated with nano-sized silica (PH105(n)), hypromellose (K15...