ASSOCIATION BETWEEN BENZALKONIUM CHLORIDE AND A POLY(ACRYLIC ACID) GEL - STUDY BY MICROFILTRATION AND MEMBRANE DIALYSIS

Interactions between benzalkonium chloride (BAK) and the respective po lymers, and the related availability of BAK in the corresponding solut ion, were studied for aqueous preparations of hydroxyethylcellulose (H EC), polyvinyl alcohol (PVA) and crosslinked poly(acrylic acid) (PAA). The study was performed by means of a crossflow filtration process wi th an alumina membrane. In the presence of the PAA gel, the rejection rate of BAK is much higher than with HEC or PVA. These results can be explained by the association of the benzalkonium cation BAK(+) with th e negative carboxylate groups or the PAA. This effect: which was confi rmed by dialysis experiments, leads to the trapping of BAK(+) inside t he polymer network and could be of interest in the reduction of the ha rmful effects of BAK observed in the treatment of eye diseases.