Controlled antibody release from a matrix of poly(ethylene-co-vinyl acetate) fractionated with a supercritical fluid

✍ Scribed by W. Mark Saltzman; Norman F. Sheppard Jr.; Mark A. Mchugh; Richard B. Dause; J. Alan Pratt; Amy M. Dodrill

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 581 KB
• Volume: 48
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1993.070480818

✦ Synopsis

SYNOPSIS

A new method is presented for controlling the rate of antibody ( Ab) release from a n inert matrix composed of poly (ethylene-co-vinyl acetate) ( EVAc) , a biocompatible polymer that is frequently used to achieve controlled release. Using supercritical propane, a parent EVAc sample ( M , = 70 kDa, M , / M , = 2.4) was separated into narrow fractions with a range of molecular weights (8.7 < M , < 165 kDa, 1.4 < M,,,/M, < 1.7). Solid particles of Ab were dispersed in matrices composed of different polymer fractions and the rate of Ab release into buffered saline was measured. The rate of Ab release from the EVAc matrix depended on molecular weight: > 90% of the incorporated Ab was released from low molecular weight fractions ( M , < 40 kDa) during the first 5 days of release, while < 10% was released from the high molecular weight fraction ( M , > 160 kDa) during 14 days of release.

No significant differences in polymer composition, glass-transition temperature, or crystallinity were identified in the different molecular weight fractions of EVAc. Mechanical properties of the polymer did depend on the molecular weight distribution, and correlated directly with Ab release rates. Because it permits rapid and reproducible fractionation of polymers, supercritical fluid extraction can be used to modify the performance of polymeric biomaterials.