The Release Behavior and Kinetic Evaluation of Diltiazem Hel from Various Hydrophilic and Plastic Based Matrices

In this study, the effects of various hydrophilic (hpmc and carbopol 971) and plastic(ethylcellulose and eudragit rlloo) polymers on the release profile of diltiazem hci frommatrix tablets were evaluated in-vitro. for this purpose, tablets containing 60 mg of diltiazemhci along with various amounts of the aforementioned polymers were prepared using the wetgranulation technique. tablets prepared were placed in a usp apparatus i dissolution testercontaining a ph-1.5 hcl solution for the first 2 h and a ph-6.8 phosphate buffer for the next10 h of the study. the amount of drug released was determined at 237 nm by a uv-visiblespectrophotometer. the results showed that all the polymers used in this study could slowdown the release of diltiazem hci from the matrices prepared. this effect, except for hpmc,generally increased proportionately with the amount of polymer. hpmc imparted the bestcontrol over drug release and could sustain it for approximately 6 h. all the matrices preparedhad a burst release initially; however, it was minimum with hpmc-containing formulations.fitting of release data to different kinetic models showed that hpmc-matrices conformedbest to hixson-crowell model, ethylcellulose-matrices to higuchi and both eudragit rl100and carbopol 97 i-formulations to either of hixson-crowell, higuchi and first-order kinetics.release exponent (n) derived from korsmeyer-peppas equation for the studied formulationsimplied that the release of diltiazem hci from hpmc-matriees was non-fickian (0.62-0.66)and that of ethylcellulose-formulations was fickian (n~o.4). the values of n for eudragitrl100 and carbopol 971-matrices ranged from 0.46-0.59, indicating that the drug releasewas mainly governed by diffusion. briefly, hpmc was found to be suitable for sustaining therelease of diltiazem hci from matrix-type tablets. nevertheless, to achieve better results withthis polymer, further investigations seem to be necessary.