Design and Evaluation of Extended Release Capsules of Acetazolamide Using Eudragit RS100 And Eudragit RL100

Utilizing the concept of incorporating drug in to the polymer matrices and extend the
drug release for prolong period of time, an attempt was made to design and evaluate
extended release capsules of acetazolamide using extended release polymers. The
initial three formulations of Acetazolamide ER capsules were formulated with Ethyl
cellulose N-7, Benecel (HPMC 15M) and Natrosol (HHX Pharm) with concentrations
of 11%, 13% and 15% respectively. However satisfactory results were not obtained
these polymers and it was decided to proceed further with high viscosity polymers
which would effectively sustain the release of drug. The F1 - F16 batches were taken
with different concentrations of Eudragit RS100 and Eudragit RL100. The
combinations of these polymers in different proportions provide varied sustained
release profiles. The optimized formulation (F12) was developed by using Eudragit
RS100 (6%) and Eudragit RL100 (4%). The dissolution profiles of formulation F12
and innovator product were compared by calculating differential factor (f1) and
similarity factor (f2). The f1 and f2 were found to be 2.97 and 69.70 respectively for
the comparison of dissolution profiles of formulation F12 and innovator product.
Infrared Spectroscopy studies were showed sharp characteristic peaks for
Acetazolamide at different wave numbers. All the above peaks appeared in optimised
formulation at same wave numbers, indicating no interaction between the drug and
the polymer. The stability studies on Acetazolamide ER capsules 500 mg in HDPE
container at 400C / 75 % RH were conducted as per ICH protocol and no significant
change was observed in the assay value after a storage period of 1 month at 400C / 75
% RH and 2 months at 400C / 75 % RH.