文档介绍：Molecular Principles of Biomaterials Spring 2003
Lecture 5: Controlled Release Devices
Last time: Using enzyme substrate and cytokine peptides to engineer biological recognition of
synthetic polymers
Today: controlled release devices and applications
principles of controlled release devices based on degradable polymers
Synthesis of controlled release devices
Theory of polymer-based controlled release
Reading: ‘Materials for protein delivery in tissue engineering,’ . Baldwin and . Saltzman,
Adv. Drug Deliv. Rev., 33, 71-86 (1998)
Controlled Release Applications in Biological Engineering and Medicine
Overview
• Controlled release: Cargo molecules (small molecule drug, protein, DNA, etc.) released to physiological
environment at a designed rate
• why develop controlled release systems?
o Recent estimates from FDA: ~10 years and $150 to develop a single new drug product- looking for added
value
o Many drugs have a narrow therapeutic index (difference between toxic level and therapeutic level)
Requires multiple injections
Poor pliance
Increased incidence of infection and hemmorhages
o Danger of systemic toxicity with more potent drugs; some drugs simply cannot be used
IL-2 promotes lymphocyte proliferation, useful as an anti-cancer drug but toxic at systemic level
(induces fever, pulmonary edema, and vascular shock)
o Targeted delivery possible
o Improves availability of drugs with short half lives in vivo
Some peptides have half-lives of a few minutes or even seconds
o Release systems can double as adjuvants for ines
• Show Figure 1 p. 347 Ratner
Where applicable:
Application Examples Active
concentration of
cargo
Provide missing soluble factors Replace deficient human growth 1-10 pM; Hormones
promoting cell differentiation, hormone in children 5-10 nM
growth, survival, or other functions
Sustained or modulated delivery of Release of anti-cancer d