pH sensitive polyelectrolyte complex of O-carboxymethyl chitosan and poly (acrylic acid) cross-linked with calcium for sustained delivery of acid susceptible drugs.
The present study investigates the ability of a polyelectrolyte complex, composed of O-carboxymethyl chitosan (O-CMC) and carbopol cross linked with calcium, as a pH-sensitive carrier for acid susceptible drugs. DSC studies were performed to confirm the formation of O-CMC-carbopol complex. Double endothermic peaks in thermogram of polyelectrolyte beads reflect the molecular changes brought in after cross-linking. FT-IR spectroscopy was used to reveal peak variation of the carboxylic groups as a function of pH 1.2 and pH 6.8. The formation of polyelectrolyte complex, on account of electrostatic interactions between the COO(-) group of carbopol and the NH(3)(+) group of O-CMC, was also confirmed by FT-IR studies. Swelling of the O-CMC-carbopol film showed a pH-dependent profile that was affected by calcium ion concentration. The swelling rate was more significant at intestinal pH because the ionization of carboxylic acid group on O-CMC and carbopol creates electrostatic repulsion. Release behavior of drug is relative to the viscosity of solution and the ionic interaction between O-CMC and carbopol. Mucous glycoprotein assay revealed that ionization of carboxylic group on the beads at intestinal pH formed a strong hydrogen bond with mucin, which was responsible for the prominent mucoadhesive property thus prolonging the intestinal residence time.
Department of Pharmaceutical Sciences, Jodhpur National University, Jodhpur, India. nayan5678@yahoo.co.in
Nayan A
NA
Gujarathi
Bhushan R
BR
Rane
Jayvadan K
JK
Patel
D053799:2-Pyridinylmethylsulfinylbenzimidazoles / Q000737:chemistry; D000180:Acrylic Resins / Q000737:chemistry*; D000818:Animals; D002118:Calcium / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D048271:Chitosan / Q000031:analogs & derivatives* / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000737:chemistry; D008297:Male; D009077:Mucins / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry; D064750:Rabeprazole; D051381:Rats; D017208:Rats, Wistar; D017550:Spectroscopy, Fourier Transform Infrared
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000180:Acrylic Resins; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D009077:Mucins; C504164:O-carboxymethylchitosan; D011145:Polyvinyls; C006912:carboxypolymethylene; D064750:Rabeprazole; C006903:carbopol 940; D048271:Chitosan; D002118:Calcium