Preparation and in vitro/in vivo evaluation of esomeprazole magnesium-modified release pellets.

To reduce the drug plasma concentration fluctuation without being destroyed by gastric fluid, novel Esomeprazole magnesium modified-release pellets (EMZ-MRPs) with suitable in vitro release profiles and good in vitro and in vivo correlation (IVIVC) were developed. Fluid-bed was used to obtain EMZ-loaded pellets by spraying drug suspension onto blank sugar pellets. The drug-loaded pellets were subsequently coated with Eudragit (R) RS30D/RL30D (ERS/ERL) aqueous dispersion to achieve sustained-release (SR) characteristics. Furthermore, the SR pellets were coated with Eudragit (R) L30D-55 (EL-55) aqueous dispersion to achieve enteric properties. Besides, isolated coating film was necessary between drug layer and SR layer, as well as SR and enteric-coated layer to protect from their possible reaction. The resulting pellets were filled into the hard gelatin capsules for in vitro release processing and single-dose pharmacokinetic study in rats. The optimal formulation achieved good SR feature both in vitro and in vivo with a relative bioavailability of 103.50%. A good IVIVC was characterized by a high coefficient of determination (r=0.9945) by deconvolution method. Compared to those of EMZ enteric-coated pellets (EMZ-ECPs, trade name NEXIUM), the in vivo study make known that the EMZ-MRPs with decreased maximum plasma concentration (C-max), prolonged peak concentration time (T-max) and mean residence time (MRT), and similar values both area under concentration-time curve from 0 to t (AUC(0-t)) and 0 to infinity (AUC(0-)). Collectively, these results manifested EMZ-MRPs had a satisfactory sustained-release behavior, a desired pharmacokinetic property, improved in vivo retention and decreased plasma drug concentration fluctuation.