Assessing the influence of media composition and ionic strength on drug release from commercial immediate-release and enteric-coated aspirin tablets

ObjectivesThe objective of this test series was to elucidate the importance of selecting the right media composition for a biopredictive in-vitro dissolution screening of enteric-coated dosage forms. MethodsDrug release from immediate-release (IR) and enteric-coated (EC) aspirin formulations was assessed in phosphate-based and bicarbonate-based media with different pH, electrolyte composition and ionic strength. Key findingsDrug release from aspirin IR tablets was unaffected by media composition. In contrast, drug release from EC aspirin formulations was affected by buffer species and ionic strength. In all media, drug release increased with increasing ionic strength, but in bicarbonate-based buffers was delayed when compared with that in phosphate-based buffers. Interestingly, the cation species in the dissolution medium had also a clear impact on drug release. Drug release profiles obtained in Blank CarbSIF, a new medium simulating pH and average ionic composition of small intestinal fluid, were different from those obtained in all other buffer compositions studied. ConclusionsResults from this study in which the impact of various media parameters on drug release of EC aspirin formulations was systematically screened clearly show that when developing predictive dissolution tests, it is important to simulate the ionic composition of intraluminal fluids as closely as possible.