Abstract :
In the present study, an attempt was made to develop the pulsatile drug delivery of Metaprolol tartrate to the colon.
Formaldehyde treated Capsule bodies were used for the preparation of pulsincaps. It was sealed with unhardened
cap of the capsule. The microspheres were prepared by emulsion solvent evaporation technique. Optimized
microsphere formulations were selected based on dissolution studies. Hydrogel plug (HPMCK100 and lactose in
1:1 ratio) having 4.5kg/cm2hardness and 100 mg weight was placed in the capsule opening and found that it was
satisfactory to retard the drug release in small intestinal fluid and to eject out the plug in colonic fluid and releasing
the microspheres into colonic fluid after a lag time criterion of 5 hours. The sealed capsules were completely coated
by dip coating method with 5% cellulose acetate phthalate to prevent variable gastric emptying. Dissolution studies
of pulsatile capsule device in media with different pH (1.2, 7.4 and6.8) showed that drug release in colon could be
modulated by optimizing the concentration of polymers in the microspheres. Drug–polymer interaction studies
indicated no interaction in between the drug and the polymer. Among all the formulations Metaprolol tartrate
microspheres prepared with cellulose acetate in 1:2 ratio shown prolonged release for a period of 12 hours. The
obtained results showed the capability of the system in delaying drug release for a programmable period of time and
to deliver the drug in the early morning hours when the hypertension is more prevalent.
Keyword :
Metaprolol tartrate; Hypertension; Pulsatile; Microspheres; Hydrogel Plug; Solvent evaporation.