A review of the chemical modification techniques of starch.

Starch is a naturally occurring storage copolymer with unique physicochemical properties. There are, however, some key structural properties of starch that can be modified in order to functionalize the copolymer to meet specific requirements. Specifically, the chemical modification of starch provides a variety of physicochemical benefits, some of which have been used previously to functionalize preformed drug delivery systems. Of the three main chemical modification methods reviewed (namely: oxidation, esterification and etherification), surface chemical oxidation introduces more pertinent physicochemical properties that increase overall drug delivery system efficacy and applicability. Surface oxidation evidently is the more preferable chemical modification method of pre-formed starch particles and has the greatest potential for further development when compared to the other reviewed chemical modification methods. The use of modified starch in clinical trials as well as the potential future implications of these systems is also included in this review.