title: Bovine albumin release and degradation analysis of dicalcium phosphate dihydrate cement.
abstract: Dicalcium phosphate dihydrate (DCPD) cement was effective in our prior study as a bone morphogenetic protein-2 (BMP-2) delivery vehicle in a rat segmental defect regeneration study. In this study, we investigated the effects of liquid-to-powder (L/P) ratio on the in vitro degradation and protein release behavior of this material. The L/P ratios used in this study ranged from 0.50 to 0.83. DCPD cylinders were formed with a diameter of 1/4" and a height of 1/4". The effect of L/P on the initial compressive strength was found to be related to the porosity of the material at different L/P level. The strength of the material in phosphate buffered solution was found to degrade roughly 20% in 14 days. The relation between the final porosity and the compressive strength after degradation was modeled with Ryshkewitch equation. A liquid-to-powder ratio of 0.55, 0.7, and 0.8 was then used to fabricate samples for the protein release kinetic study. The low porosity (L/P = 0.55) group was found to have the fastest release rate, while the L/P = 0.8 group had the lowest. More then 60% of the loaded protein was released after 10 hours in all three groups with a final total release ranging between 75% and 93%. The findings suggested that the protein release profile of DCPD cements can be adjusted by the L/P ratio.
authors.affiliation: Department of Biomedical Engineering, Indiana University-Purdue University Indianapolis, 1102 South Dr. Rm 146, Indianapolis, IN 46202, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Metz
authors.forename: Peter
authors.initials: P
authors.lastname: Sargent
authors.forename: Tien-Min G
authors.initials: TM
authors.lastname: Chu
mesh_terms: D020341:Absorbable Implants; D000042:Absorption; D001843:Bone Cements / Q000737:chemistry* / Q000627:therapeutic use*; D002130:Calcium Phosphates / Q000737:chemistry*; D019245:Compressive Strength; D003692:Delayed-Action Preparations / Q000008:administration & dosage* / Q000737:chemistry*; D004058:Diffusion; D008422:Materials Testing; D016062:Porosity; D012710:Serum Albumin, Bovine / Q000008:administration & dosage* / Q000737:chemistry*
chemical_list: D001843:Bone Cements; D002130:Calcium Phosphates; D003692:Delayed-Action Preparations; D012710:Serum Albumin, Bovine; C494366:calcium phosphate, dibasic, dihydrate