Formulation of gastroresistant tablets containing sodium alendronate-loaded blend microparticles

Sodium alendronate is an antiresorptive drug used for the treatment of postmenopausal osteoporosis. However, its oral administration is associated with low bioavailability and gastroesophageal irritation. This work aimed at developing tablets containing sodium alendronate-loaded microparticles by direct compression to achieve a safe and effective form. The parameters evaluated were average weight, hardness, thickness and drug content. In vitro release tests were carried out using simulated gastric and intestinal fluids, and the profiles were analyzed through the Korsmeyer-Peppas mono- or biexponential dependent approaches. Tablets presented adequate average weight, thickness, good mechanical properties and drug content close to 100%. Moreover, the formulation released less than 11% of sodium alendronate in gastric fluid, exhibiting a good gastroresistance. At pH 6.8, almost 100% of the drug was released in 12h, showing a prolonged profile. The mathematical modeling indicated that the experimental data was better fitted to the biexponential equation. Furthermore, a good correlation coefficient was obtained for the Korsmeyer-Peppas model and the release exponent suggested that the drug dissolution was driven by anomalous transport. In conclusion, the microparticulated tablets can be considered a promising alternative for oral delivery of sodium alendronate.