Biomaterials 24 (2003) 3333–3343 Review Pectin-based systems for colon-specific drug delivery via oral route LinShu Liu a, *, Marshall L. Fishman a , Joseph Kost b , Kevin B. Hicks a a US Department of Agriculture, ARS, Eastern Regional Research Center, 600 East Mermaid, Lane, Wyndmoor, PA 19038, USA b Department of Chemical Engineering, Ben-Gurion University, Beer-Sheva 84105, Israel Received 25 November 2002; accepted 24 March 2003 Abstract Pectin-derived matrices are now being examined and tested for controlled drug delivery. Pectin is intact in the upper gastrointestinal tract and degraded by colonic microflora. The composition of this microflora remains relatively consistent across a diverse human population. Thus, pectin-derived drug carriers provide promising potential for colon-specific drug delivery. This paper reviews recent developments in pectin-derived formulations. Subjects reviewed include gelation of pectin, calcium cross-linked pectinate, composites of pectin and other polymers, technologies to fabricate pectin into useful drug delivery vehicles, and methods to evaluate release kinetics of incorporated drugs. This article discusses advantages, limitations, and possible future developments in pectin-based formulations with particular emphasis on the field of colon-specific drug delivery. Published by Elsevier Science Ltd. Keywords: Pectin; Controlled release; Oral administration; Colon-specific drug delivery 1. Introduction For most of civilized history, there was no clear difference in the way in which humans consumed food and medicine. To date, oral delivery is still the preferred route of drug administration, especially for chronic therapies where repeated administration is required. Oral administration offers patients less pain, greater convenience, higher likelihood of compliance, and Contents 1. Introduction ................................................ 3333 2. Physiology of human GI tract and strategies to deliver drugs to the colon site .............. 3334 3. Gelation of pectin ............................................. 3335 4. Calcium pectinate .............................................. 3336 5. Combination of pectin and other polymers ................................ 3338 5.1. Pectin and ethylcellulose ....................................... 3339 5.2. Combination of pectin and hydroxypropylmethyl cellulose ..................... 3339 5.3. Polyelectrolyte of pectin with polycations .............................. 3339 6. Current status and challenges ....................................... 3341 References .................................................... 3341 *Corresponding author. Tel.: +1-215-233-6486; fax: +1-215-233- 6406. E-mail address: lsliu@arserrc.gov (L. Liu). 0142-9612/03/$ - see front matter Published by Elsevier Science Ltd. doi:10.1016/S0142-9612(03)00213-8