Asian Journal of Pharmaceutical and Clinical Research Vol.2 Issue 3, July-September 2009
Preparation of Carvedilol Tablets
The conventional wet granulation procedure was employed to formulate core tablets of carvedilol. The ingredients consisting of carvedilol, lactose monohydrate, polyplasdone INF 10 and collidal silicon dioxide is taken intragranular and PVP-K 30 in water is used to granulate the mass. The mass is then dried and passed through the 25 mesh sieve. Extragranular polyplasdone INF 10, collidal silicon dioxide and magnesium stearate is sifted through 60 mesh sieve and mixed with the dried granules. Tablets were prepared using 10 x 6.4 mm oval punch.
Aqueous Coating of the Tablets
Aqueous film coating procedure was applied. The different levels of tween 80, 0 %, 3 %, 6 % and 10 % was prepared to observe the solubility and dissolution rate of the carvedilol. Tween 80 was first dissolved in distilled water with stirring using a variable speed propeller stirrer and then polyvinyl alcohol (PVA), talc and triethyl citrate (TEC) was added with stirring to the mixture and stirring was continued to obtain homogenous dispersion. The coating dispersion was diluted sufficiently to produce the 15 % w/w of the solid content. Four batches of coated tablets T1, T2, T3 and T4 were prepared by applying PVA and Tween 80. Coated tablet contains 0 %, 3 %, 6 % and 10 % of Tween 80. The pan rotation was adjusted to 20 rpm for better tumbling
effect to the tablets.
Evaluation of Tablets
measured using a Stokes Monsanto Hardness Tester. The percentage friability of the core tablets was determined by following USP procedure. The friability was determined by subjecting a sample of core tablets equivalent to 6.5 g to abration in automated USP friabilater for 100 rotations. The dedusted tablets were weighed and percentage friability was calculated from the difference in the weight of tablets before and after the friability test. The disintegration test of the core tablets was carried out using USP XXIII disintegration tester (model ED-2, Electrolab, Mumbai). Six tablets were placed individually in each tube of the apparatus. The disintegration test was performed in distilled water; the temperature of water bath was maintained at 37±0.5° through out the test. Dissolution studies of the coated tablets were carried by employing the USP II dissolution test apparatus in pH 6.8 phosphate buffer, 900 ml. The temperature of the dissolution medium is maintained at 37±0.5° with a stirring speed of 50 rpm. Aliquot of the dissolution medium was withdrawn at 10 minute time interval for 60 minute and sampled volume is replaced with the equal volume of buffer maintained at same temperature.
RESULTS AND DISCUSSION
A wet granulation procedure was employed to produce a tablet of carvedilol. Lactose monohydrate was selected as filler in the formulation as tablets containing lactose are reported to show fast disintegration. Good friability and low wet variation with no signs of sticking, binding and capping. The formula was designed to
have sufficient superdisintegrant
tablets/coated tablets was determined by official method. The percentage practical weight gain for each batch of coated tablets was computed from the average
tablet weight of
each tablet. Hardness of
minimize the disintegration time and to generate a pulsed release during the dissolution. Crospovidone was incorporated in two steps, 3 % was added intragranular and dry mixed before wet granulation.