چكيده لاتين :
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 from
matrix tablets were evaluated in-vitro. For this purpose, tablets containing 60 mg of diltiazem
HCI along with various amounts of the aforementioned polymers were prepared using the wet
granulation technique. Tablets prepared were placed in a USP apparatus I dissolution tester
containing a pH-1.5 HCl solution for the first 2 h and a pH-6.8 phosphate buffer for the next
10 h of the study. The amount of drug released was determined at 237 nm by a UV-visible
spectrophotometer. The results showed that all the polymers used in this study could slow
down 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 best
control over drug release and could sustain it for approximately 6 h. All the matrices prepared
had a burst release initially; however, it was minimum with HPMC-containing formulations.
Fitting of release data to different kinetic models showed that HPMC-matrices conformed
best to Hixson-Crowell model, ethylcellulose-matrices to Higuchi and both Eudragit RL100
and 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 formulations
implied 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 Eudragit
RL100 and Carbopol 971-matrices ranged from 0.46-0.59, indicating that the drug release
was mainly governed by diffusion. Briefly, HPMC was found to be suitable for sustaining the
release of diltiazem HCI from matrix-type tablets. Nevertheless, to achieve better results with
this polymer, further investigations seem to be necessary.
