Release pattern of dyphylline tablets containing polyion complexes made from chitosan with anionic polymers

ABSTRACT

With a view to the application of chitosan [CS] for drug delivery, interpolymer complexes of CS with each of carbopol 934 [CP] and carboxymethyl cellulose [CMC] were investigated employing viscosity measurement. The stoichiometry of binding were 14 and 12 for CSCMC and CSCP complexes, respectively. Physical mixtures 50% of each CSCMC and CSCP in different ratios including those of their complexes were directly compressed to tablets containing 50% w/w of dyphylline as a model drug. In acid medium, the most precise sustained behavior from CSCMC and CSCP matrices were found at ratios of 14 and 21, respectively, indicating the formation of the complex during dissolution. In phosphate buffer, however, CS disintegrated and released from the physical mixture was dependent on the weight fraction of either CMC or CP. The drug release pattern from increased pH milieu was almost similar to that in acid medium. Even low percentage of matrix [CSCP and 10% concentration], also showed sustained release effect