BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 peptide enca "。 Ag stabilizer solution phere sizes-05-100 um ed in microsphere fabrication o Poly(vinyl alcohol) o Poly(vinyl pyrrolidone) o Poly(ethylene glycol-b-propylene glycol)(e.g. Pluronics Inhibit particle coalescence by steric interference between droplets Factors in encapsulation efficiency: ( tied to many of same molecular issues as release o Bonding between drug and matrix o Hydrophilic proteins are poorly encapsulated ouble emulsion microparticle fabrication Allows entrapment of hydrophilic molecules, proteins Inner ag phase encapsulation Adsorbed stabilize Stabilizer solution(aq) Solid polymer Lecture 5- Controlled Release Devices 9 of 14BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 peptide encapsulation Aq. Stabilizer solution • sphere sizes ~ 0.5 – 100 µm • Stabilizers used in microsphere fabrication: o Poly(vinyl alcohol) o Tweens o Poly(vinyl pyrrolidone) o Poly(ethylene glycol-b-propylene glycol) (e.g. PluronicsTM) • Inhibit particle coalescence by steric interference between droplets • Factors in encapsulation efficiency: (tied to many of same molecular issues as release) o Bonding between drug and matrix o Hydrophilic proteins are poorly encapsulated Double emulsion microparticle fabrication: • Allows entrapment of hydrophilic molecules, proteins Stabilizer solution (aq) Protein encapsulation Solid polymer Adsorbed stabilizer Inner aq. phase Lecture 5 – Controlled Release Devices 9 of 14