title: Carboxymethyl high amylose starch (CM-HAS) as excipient for Escherichia coli oral formulations.
abstract: Carboxymethyl high amylose starch (CM-HAS) is proposed as a novel excipient for oral tablet formulation of bioactive agents ensuring their protection in the stomach and delivery in the intestine. Three variants of CM-HAS, with different degrees of substitution, were synthesized by starch treatment with various amounts of monochloroacetic acid. The products were dried in powder form and tablets were obtained by direct compression of mixed powders of polymeric excipient and lyophilized Escherichia coli (E. coli) bacteria. Dosage forms of CM-HAS are unswollen and compact in acidic medium, ensuring protection of active agents against acidity. Release of bacteria from CM-HAS tablets is based on the fast swelling of the tablets during the passage from gastric acidity to alkaline intestinal medium, enzymatic hydrolysis triggering their rapid, almost total dissolution. The bacteria thus formulated displayed higher survival rates in acidic gastric conditions and for longer periods than the free bacteria or than the bacteria formulated with the non-derivatized starch. The CM-HAS selected matrix also assured a good viability of bacteria after 6 months under refrigeration.
authors.affiliation: Department of Chemistry and Biochemistry, Université du Québec à Montréal, Montréal, Qué., Canada.
authors.forename: Carmen
authors.initials: C
authors.lastname: Calinescu
authors.forename: Jérôme
authors.initials: J
authors.lastname: Mulhbacher
authors.forename: Eric
authors.initials: E
authors.lastname: Nadeau
authors.forename: John Morris
authors.initials: JM
authors.lastname: Fairbrother
authors.forename: Mircea Alexandru
authors.initials: MA
authors.lastname: Mateescu
mesh_terms: D000688:Amylose / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D001826:Body Fluids / Q000737:chemistry; D002240:Carbohydrate Sequence; D003432:Cross-Linking Reagents; D004339:Drug Compounding; D004355:Drug Stability; D004926:Escherichia coli; D005079:Excipients / Q000138:chemical synthesis / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010194:Pancreatin / Q000737:chemistry; D011312:Pressure; D019936:Probiotics / Q000008:administration & dosage*
chemical_list: D003432:Cross-Linking Reagents; D005079:Excipients; D010194:Pancreatin; D000688:Amylose