Pectin gelation with chlorhexidine: Physico-chemical studies in dilute solutions.
Low methoxyl pectin is known to gel with divalent cations (e.g. Ca(2+), Zn(2+)). In this study, a new way of pectin gelation in the presence of an active pharmaceutical ingredient, chlorhexidine (CX), was highlighted. Thus chlorhexidine interactions with pectin were investigated and compared with the well-known pectin/Ca(2+) binding model. Gelation mechanisms were studied by several physico-chemical methods such as zeta potential, viscosity, size measurements and binding isotherm was determined by Proton Nuclear Magnetic Resonance Spectroscopy ((1)H NMR). The binding process exhibited similar first two steps for both divalent ions: a stoichiometric monocomplexation of the polymer followed by a dimerization step. However, stronger interactions were observed between pectin and chlorhexidine. Moreover, the dimerization step occurred under stoichiometric conditions with chlorhexidine whereas non-stoichiometric conditions were involved with calcium ions. In the case of chlorhexidine, an additional intermolecular binding occurred in a third step.
Université de Lyon, Institut des Sciences Analytiques, UMR 5280, CNRS, Université Lyon 1, ENS Lyon - 5, rue de la Doua, F-69100 Villeurbanne, France. Electronic address: manon.lascol@univ-lyon1.fr.
Manon
M
Lascol
Université de Lyon, Laboratoire d'Automatique et de Génie des Procédés, UMR CNRS 5007, Université Lyon 1, F-69622 Villeurbanne, France; Université de Lyon, Université Lyon 1, ISPB-School of Pharmacy, F-69008 Lyon, France. Electronic address: sandrine.bourgeois@univ-lyon1.fr.
Sandrine
S
Bourgeois
Université de Lyon, Institut des Sciences Analytiques, UMR 5280, CNRS, Université Lyon 1, ENS Lyon - 5, rue de la Doua, F-69100 Villeurbanne, France. Electronic address: florence.guilliere@univ-lyon1.fr.
Florence
F
Guillière
Université de Lyon, Institut des Sciences Analytiques, UMR 5280, CNRS, Université Lyon 1, ENS Lyon - 5, rue de la Doua, F-69100 Villeurbanne, France. Electronic address: marie.hangouet@isa-lyon.fr.
Marie
M
Hangouët
Université de Lyon, Institut des Sciences Analytiques, UMR 5280, CNRS, Université Lyon 1, ENS Lyon - 5, rue de la Doua, F-69100 Villeurbanne, France. Electronic address: guy.raffin@isa-lyon.fr.
Guy
G
Raffin
Université de Lyon, Institut des Sciences Analytiques, UMR 5280, CNRS, Université Lyon 1, ENS Lyon - 5, rue de la Doua, F-69100 Villeurbanne, France. Electronic address: pedro.marote@univ-lyon1.fr.
Pedro
P
Marote
Université de Lyon, Institut des Sciences Analytiques, UMR 5280, CNRS, Université Lyon 1, ENS Lyon - 5, rue de la Doua, F-69100 Villeurbanne, France. Electronic address: pierre.lanteri@univ-lyon1.fr.
Pierre
P
Lantéri
Université de Lyon, Institut des Sciences Analytiques, UMR 5280, CNRS, Université Lyon 1, ENS Lyon - 5, rue de la Doua, F-69100 Villeurbanne, France. Electronic address: claire.bordes@univ-lyon1.fr.
Claire
C
Bordes
D002118:Calcium / Q000737:chemistry; D055598:Chemical Phenomena; D002710:Chlorhexidine / Q000737:chemistry*; D005782:Gels; D010368:Pectins / Q000737:chemistry*; D012996:Solutions; D014783:Viscosity
D005782:Gels; D012996:Solutions; D010368:Pectins; D002710:Chlorhexidine; D002118:Calcium
Binding isotherm; Chlorhexidine; Gelation; Low methoxyl pectin; Polysaccharide