<I>In vitro-in vivo</I> correlation as a tool for predicting bioavailability of aspirin liquisolid tablets

Background: Aspirin is widely utilized for cardiovascular event prevention and fever management, making it one of the most frequently prescribed medications. It boasts a singular mechanism of action, specifically targeting thromboxane A2 production to prevent platelet activation, unmatched by other antiplatelet agents. The majority of commercial aspirin products are plagued by gastrointestinal sideeffects and inconsistent absorption, ultimately reducing their bioavailability and therapeutic potential. These observations underscore the critical need for aspirin formulation that exhibit optimal absorption and minimized variability. The liquisolid process is an age-long approach for improving oral drug solubility and absorption. Methods: Herein, we formulated different aspirin liquisolid tablets (ALS1-ALS15) and exposed them to pre and post-compression studies to identify the optimized formulation, after which we compared and investigated the predicted plasma concentration-time profiles of aspirin prototype drug from in vitro dissolution results using a mathematical convolution approach for In vitro-in vivo correlation (IVIVC) study. Results: All formulations had near-excellent flowability. The differential scanning calorimetry and Fourier transform infra-red spectral showed no major interactions between aspirin crystals and the excipients used in this study. Formulation ALS5 exhibited preferred physicochemical properties and was therefore chosen as the optimal formula. The time to attain peak plasma concentration was similar for both the test and the reference product (0.5 h). In contrast, their maximum plasma concentration deviates by 1.23 and 21.75 percent from the authentic reference values derived from the literature. Conclusion: The percentage of predicted errors achieved revealed that the convolution technique could predict plasma drug levels of aspirin liquisolid tablets as per FDA guidelines.