Entecavir hydrate

Zhang C, et al. International Journal of Pharmaceutics, 2019, 560, 27-34.

This case study highlights the experimental incorporation of Entecavir (ETV) into poly(lactic-co-glycolic acid) (PLGA) microspheres using solid microencapsulation strategies optimized for poorly soluble actives. Three preparative routes-in situ S/O/W, classical S/O/W, and spray-drying S/O-were systematically evaluated. In the in situ S/O/W method, ETV was first dissolved in DMSO and precipitated as fine solids upon dispersion into PLGA-DCM solution, followed by PVA-stabilized emulsification and solvent evaporation to yield solidified microspheres. The classical S/O/W method relied on ultrasonic dispersion of crystalline ETV in PLGA-DCM, producing a homogeneous suspension before aqueous emulsification. Alternatively, spray drying of an ETV-PLGA suspension generated uniform particles through rapid solvent removal. Across methods, the optimized microspheres achieved ~86 µm mean size and 13% drug loading, with DSC and PXRD confirming crystalline-amorphous coexistence. In vitro and in vivo studies established dissolution-controlled release, supporting the applicability of Entecavir-loaded PLGA microspheres for sustained anti-HBV therapy.