Skip to main content
. Author manuscript; available in PMC: 2016 Dec 10.
Published in final edited form as: J Control Release. 2015 Oct 9;219:2–7. doi: 10.1016/j.jconrel.2015.10.005

Table 2.

History of drug delivery technology from 1950 to the present and the technology necessary for the future.

Year
1950    1980    2010    2040
1st Generation 2nd Generation 3rd Generation
Basics of Controlled Release Smart Delivery Systems Modulated Delivery Systems
Oral delivery

  • Twice-a-day, once-a-day

 Zero-order release

  • First-order vs zero-order

 Poorly soluble drug delivery

  • Non-toxic excipients
Transdermal delivery

  • Once-a-day, once-a-week

 Peptide & protein delivery

  • Long-term depot using biodegradable polymers

  • Pulmonary delivery

 Peptide & protein delivery

  • Delivery for >6 months

  • Control of release kinetics

  • Non-invasive delivery
Drug release mechanisms

  • Dissolution

  • Diffusion

  • Osmosis

  • Ion-exchange

 Smart polymers & hydrogels

  • Environment-sensitive

  • Self-regulated release (working only in vitro)

 Smart polymers & hydrogels

  • Signal specificity & sensitivity

  • Fast response kinetics (working in vivo)
Nanoparticles

  • Tumor-targeted delivery

  • Gene delivery

 Targeted drug delivery

  • Non-toxic to non-target cells

  • Overcoming blood-brain barrier
Successful control of physicochemical properties of delivery systems Inability to overcome biological barriers Need to overcome both physicochemical and biological barriers