Silica microparticles for sustained zero-order release of an anti-CD40L antibody.

Silica microparticle hydrogel depot (HG) formulation was prepared using spray drying of silica-based sol-gels for the sustained delivery of MR1 antibody which binds to CD40 ligand (CD40L). The formulation was tested in vitro for antibody release, surface morphology, particle size, rheology, and injectability. In vivo pharmacokinetic evaluation was performed for the microparticle formulation and free MR1 antibody in BALB/c female mice. Serum samples up to day 62 were assessed using an enzyme-linked immunosorbent assay. In vitro release indicated that the MR1 antibody was uniformly encapsulated in silica microparticles, and less than 5% burst release of the antibody was observed. In vivo pharmacokinetics showed a zero-order release up to 62 days from the MR1 silica microparticle HG-controlled release composition.