title: Synthesis and characterization of biodegradable networks providing saturated-solution prolonged delivery.
abstract: Numerous peptide drugs require continuous and local delivery to obtain optimum therapeutic effect. Herein, we describe the incorporation of a model peptide drug, vitamin B12, as well as goserelin acetate, in biodegradable elastomer cylinders through photo-cross-linking. The elastomer was prepared from acrylated star-poly(epsilon-caprolactone-co-D,L-lactide). Release was manipulated through the incorporation of poly(ethylene glycol) diacrylate (PEGD) into the network at concentrations up to 30% (w/w). The PEGD in the network caused rapid swelling that remained constant throughout the release period. The degree of swelling was low, ranging from 10 to 45% (w/w), and increasing as the PEGD content increased. Release proceeded with a minimal initial burst, and extended periods of nearly constant release, ranging from approximately 5 to 70% mass fraction released, were obtained. The release rate was independent of particle size and increased as the cylinder diameter decreased, as the amount of PEGD increased, as the molecular weight of PEGD increased, and as the agent loading increased. Moreover, goserelin acetate, which has a comparable diffusivity but greater aqueous solubility, was released at a greater rate than vitamin B12. This release behavior is explained as a balance between agent dissolution in the swollen polymer matrix and diffusion through the polymer matrix bulk.
authors: Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada K7L 3N6. brian.amsden@chee.queensu.ca
authors: Brian
authors: B
authors: Amsden
authors: Gauri
authors: G
authors: Misra
authors: Meghan
authors: M
authors: Marshall
authors: Norma
authors: N
authors: Turner
mesh_terms: D001673:Biodegradation, Environmental; D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D020724:Elastomers / Q000008:administration & dosage*; D017273:Goserelin / Q000008:administration & dosage* / Q000737:chemistry; D008970:Molecular Weight; D011092:Polyethylene Glycols / Q000008:administration & dosage*; D012995:Solubility; D014805:Vitamin B 12 / Q000008:administration & dosage* / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D020724:Elastomers; C437167:poly(ethylene glycol)diacrylate; D017273:Goserelin; D011092:Polyethylene Glycols; D014805:Vitamin B 12