The correlation between zeta potential and mucoadhesion strength on pig vesical mucosa.
The detachment forces of various polymers are frequently measured to determine their mucoadhesion strength. As the process of mucoadhesion is a consequence of interactions between the mucus layer on mucosa and mucoadhesive polymers, it is greatly dependent on mucus and polymer structure including their charge. It is also known that the glycosaminoglycan layer, which covers the urinary bladder mucosa surface, is highly negatively charged. Therefore, by measuring the zeta potential of polymer dispersions and mucosal homogenates an insight into electrostatic interactions during mucoadhesion can be obtained. In our experiments we chose three polymers, two anionic (polycarbophil, PC; sodium carboxymethyl cellulose, CMCNa) and one cationic (chitosan hydrochloride, CH), for which we expected different zeta potential values and different mucoadhesion strengths. The correlation between the zeta potential and the detachment force was determined. In addition to that, the zeta potential of the scraped surface layer of pig urinary bladders was measured to confirm its negative value. The mucoadhesion strength decreased in the following order: CH>CMCNa=PC. The zeta potentials for all three polymers and for porcine vesical mucosal homogenates were measured in Tyrode solution and two NaCl solutions with different ionic strengths. The lower values of the detachment force correlated well with the more negative zeta potential of the polymer, which might be a consequence of the greater repulsion between negative charges of polymers and glycosaminoglycans.
Faculty of Pharmacy, University of Ljubljana, Slovenia. marija.bogataj@ffa.uni-lj.si
Marija
M
Bogataj
Tomaz
T
Vovk
Mojca
M
Kerec
Ales
A
Dimnik
Iztok
I
Grabnar
Ales
A
Mrhar
D000180:Acrylic Resins / Q000737:chemistry*; D000268:Adhesiveness; D000818:Animals; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D002686:Chitin / Q000031:analogs & derivatives* / Q000737:chemistry*; D048271:Chitosan; D004337:Drug Carriers / Q000737:chemistry*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D055672:Static Electricity; D013552:Swine; D001743:Urinary Bladder / Q000737:chemistry; D019459:Urothelium / Q000737:chemistry*
D000180:Acrylic Resins; D004337:Drug Carriers; D002686:Chitin; C030312:calcium polycarbophil; D048271:Chitosan; D002266:Carboxymethylcellulose Sodium