Lisinopril is an
angiotensin-converting enzyme (
ACE) inhibitor, primarily used for the treatment of
hypertension,
congestive heart failure, and
heart attack. It belongs to BCS class III having a half-life of 12 hrs and 25% bioavailability. The purpose of the present work was to develop a press-coated, floating-pulsatile drug delivery system. The core
tablet was formulated using the super-disintegrants crosprovidone and
croscarmellose sodium. A press-coated
tablet (barrier layer) contained the
polymer carrageenan,
xanthan gum, HPMC K4M, and HPMC K15M. The buoyant layer was optimized with HPMC K100M,
sodium bicarbonate, and
citric acid. The
tablets were evaluated for physical characteristics, floating lag time, swelling index, FTIR, DSC, and in vitro and in vivo behavior. The 5% superdisintgrant showed good results. The FTIR and DSC study predicted no chemical interactions between the drug and
excipients. The formulation containing
xanthan gum showed drug retaining abilities, but failed to float. The
tablet containing HPMC K15M showed a high swelling index. The lag time for the
tablet coated with 200 mg
carrageenan was 3±0.1 hrs with 99.99±1.5% drug release; with 140 mg HPMC K4M, the lag time was 3±0.1 hrs with 99.71±1.2% drug release; and with 120 mg HPMC K15M, the lag time was 3±0.2 hrs with 99.98±1.7% drug release. The release mechanism of the
tablet followed the Korsmeyer-Peppas equation and a first-order release pattern. Floating and lag time behavior have shown good in vitro and in vivo correlations.