Preparation and evaluation of alendronate sodium solid lipid nanoparticles with high oral bioavailability in rats

Low oral bioavailability of alendronate sodium (ALE) significantly limits its clinical application. However, few studies focus on preparing ALE solid lipid nanoparticles (ALE-SLNs) and investigating its oral bioavailability in vivo due to highly hydrophilic property of ALE. In this study, ALE-SLNs were prepared through high-speed shearing combined with ultrasonic treatment method. ALE-SLNs were evaluated by average particle size, electric potential, encapsulation efficiency (EE), and drug loading (DL). Our results showed that the average EE and DL reached 62.56±0.94% and 6.26±0.09% (n=3), respectively. 120.27±1.17nm, 0.29±0.13 and -19.1±0.27 mV (n=3) were obtained in the average particle size, polydispersity index and zeta potential, respectively. The stability test showed that ALE-SLNs remained stable for more than 2 months at 4°C. After oral administration of ALE-SLNs (4.5mg/kg), the bioavailability was 2.17 times higher than that of ALE solution (86.82±3.6 vs 40.1±1.3μg) in rats. Our results indicate that high-speed shearing combined with the ultrasound method is simple and rapid to prepare ALE-SLNs. SLNs can improve the oral delivery of ALE in rats, which may exert beneficial effects in clinical applications.