Acta Pharm. 62 (2012) 105-114
Short communication
Formulation
and evaluation of delayed-onset extended-release tablets of metoprolol tartrate
using hydrophilic-swellable polymers
SUBHASH CHAND DADARWAL, SARIKA MADAN and SHYAM
SUNDER AGRAWAL
agrawal.shyam01@gmail.com
Delhi Institute of
Pharmaceutical Sciences and Research (Formerly College of Pharmacy) University
of Delhi Pushp Vihar, Sec-III, New Delhi-110017, India
Accepted December 28, 2011
In view of the circadian rhythm of cardiovascular diseases, a delayed-onset extended-release (DOER) formulation of metoprolol tartrate (MT) was prepared. This was achieved through dissolution-guided optimization of the proportion of Methocel K4M and Methocel K15M. Core erosion ratio was greater than 50 %, thereby showing steady release of the drug after the lag time until complete dissolution. Optimized formulation produced a lag phase of 6 h followed by complete release of 98.7 ± 2.1 % in 24 h. Water uptake study revealed that Methocel K15M has lower water uptake (30 ± 1 %) than methocel K4M (40 ± 2 %) after 24 h. Axial swelling of polymers was higher than swelling in the radial direction. Drug-polymer interaction study precludes any interaction between drug and polymer. Such a drug delivery system may provide a viable alternative for effective management of hypertension and other related disorders. This work also proposes an approach to attain DOER for a hydrophilic drug by using a hydrophilic swellable polymer in press coat.
Keywords: metoprolol tartrate, delayed-onset extended-release (DOER),
core erosion ratio