Introduction: Hydrodynamically balanced system (HBS) possesses prolonged and continuous
delivery of the drug to the gastrointestinal tract which improves the rate and extent of medications
that have a narrow absorption window. The objective of this work was to develop a Hydrodynamically
Balanced System (HBS) of Metoprolol Succinate (MS) as a model drug for sustained stomach specific
Methods: Experimental batches were designed according to 3(2) Taguchi factorial design. A total of 9
batches were prepared for batch size 100 capsules each. Formulations were prepared by physically
blending MS with polymers followed by encapsulation into hard gelatin capsule shell of size 0. Polymers
used were Low Molecular Weight Chitosan (LMWCH), Crushed Puffed Rice (CPR), and Hydroxypropyl
Methylcellulose K15 M (HPMC K15M). Two factors used were buoyancy time (Y1) and
time taken for 60% drug release (T60%; Y2).
Results: The drug excipient interaction studies were performed by the thermal analysis method which
depicts that no drug excipient interaction occurs. In vitro buoyancy studies and drug release studies revealed
the efficacy of HBS to remain gastro retentive for a prolonged period and concurrently sustained
the release of MS in highly acidic medium. All formulations followed zero-order kinetics.
Conclusion: Developed HBS of MS with hydrogel-forming polymers could be an ideal delivery system
for sustained stomach specific delivery and would be useful for the cardiac patients where the prolonged
therapeutic action is required.