POMPILIA ISPAS-SZABO
Adjunct Professor and consultant in pharmaceutical development Department of Chemistry Université du Québec à Montréal Montreal, Canada

Co-author: 
MIRCEA ALEXANDRU MATEESCU
Professor of Biochemistry
Department of Chemistry and PharmaQAM Center
Université du Québec à Montréal Montreal, Canada

Abstract

Despite many decades of their usage in pharmaceutical industry, modified starches continue to reveal new perspectives as functional excipients. CarboxyMethyl Starch (CMS), mainly known in the industry as a powerful disintegrant, was more recently proposed as a matrix-forming polymer able to delay the drug release and provide a chronodelivery of various bioactive agents. CMS can also offer gastro-protection of pharmaceutical forms obtained by a solvent free coating procedure.  Worth to note is that the same chemistry (same reagents and processes) could generate excipients exhibiting different properties. In the context of a long and costly process engaged for the approval of new chemical entities, the use of old excipients could be a strategic tool in the development of novel drug delivery systems.

INTRODUCTION

There is an increased need for non-toxic, biocompatible, biodegradable and natural sourced excipients. In the past, physically modified starches were extensively used in pharmaceutical industry as binders, fillers or thickening agents and more recently, chemically modified forms - crosslinked starch (Contramid^®) – were integrated in once-a-day commercial products able to afford a controlled drug delivery. When ionic groups such as carboxymethyl were grafted on its backbone chains, starch extended its functionality either as gastro-protective excipient (1) or excipient for oral vaccines (2). Associations with chitosan generated self-assembled structures stabilized via weak forces (i.e. electrostatic and hydrogen bonds) which were able to ensure gastro-protection and intestinal delivery of enzymes (3), peptides or probiotics (1). CMSs complexed with calcium or phospholipids have shown their potential in challenging formulations (1). Commercial cross-linked CMS, also called sodium starch glycolate is well known as an intra- and inter-granular super-disintegrant in pharmaceutical and nutraceutical industry under various trade names i.e. Glyc ...